Methadone pharmacokinetics in opioid agonist treatment: Influencing factors and clinical implications

BACKGROUND

A considerable inter-individual variability has been reported in the relationship between methadone doses applied and serum concentrations achieved in methadone maintenance treatment. However, the underlying causes for this variability are not fully understood.

OBJECTIVES

We investigated the influence of genetic, pathophysiological and pharmacological factors on serum methadone concentration-to-dose ratio (CDR) and discussed the clinical implications of the findings.

METHODS

We used data from two retrospective laboratory databases and a prospective cohort study to investigate the impact on methadone CDR of hepatic cytochrome P450 enzyme system (CYP) genetic polymorphisms, age, sex, concomitant medication, liver fibrosis and body mass index through linear mixed model analyses.

FINDINGS

A positive association was found between CDR and the homozygous CYP2B6*6 genotype, concurrent treatment with CYP3A4 inhibitors and body mass index. CDR was lower among women and during concomitant use of CYP inducers. CDR was not associated with age or the degree of liver fibrosis in our investigations.

CONCLUSIONS

This research work supports the need for individually tailored dosage considering the various factors that influence methadone CDR. The gained knowledge can contribute to reducing the risks associated with the treatment and optimizing the desired outcomes.

The clinical relevance of dupilumab serum concentration in patients with atopic dermatitis: a two-center prospective cohort study

BACKGROUND

Dupilumab is prescribed in one dosage across adult atopic dermatitis patients. Differences in drug exposure may explain variation in treatment response.

OBJECTIVE

Investigating the clinical relevance of dupilumab serum concentration in atopic dermatitis in real-world practice.

METHODS

In two centres (Netherlands, UK), adults treated with dupilumab for atopic dermatitis were evaluated for effectiveness and safety pre-treatment and at 2, 12, 24 and 48 weeks; trough serum samples were analysed for dupilumab concentration at corresponding time points.

RESULTS

In 149 patients, median dupilumab levels during follow-up ranged from 57.4-72.4μg/mL. Levels showed high inter-patient and low intra-patient variability. No correlation was found between levels and ΔEASI. At 2 weeks, levels of ≥64.1μg/mL predict EASI ≤ 7 at 24 weeks (specificity:100%, sensitivity:60%;p = 0.022). At 12 weeks, ≤32.7μg/mL predicts EASI > 7 at 24 weeks (sensitivity:95%, specificity:26%;p = 0.011). Inverse correlations were found between baseline EASI and levels at 2, 12 and 24 weeks (r=-0.25-0.36;p ≤ 0.023). Low levels were particularly observed in patients with adverse events, treatment interval deviation and discontinuation.

CONCLUSION

At the on-label dosage, the measured range of dupilumab levels does not seem to yield differences in treatment effectiveness. However, disease activity does seem to influence dupilumab levels - higher baseline disease activity results in lower levels at follow-up.

The Optimal Dosing Regimen of Super Bioavailable Itraconazole in Obesity: An Experimental Rat Model Study

Background Obesity may alter tissue distribution and clearance of several drugs, especially lipophilic ones. Itraconazole, a lipophilic drug, has been recently introduced in a super-bioavailable formulation (SB-ITZ) for the treatment of dermatophytosis. Evidence regarding optimal dosing of SB-ITZ in obesity is lacking. A current experimental study was planned to analyze tissue concentrations of SB-ITZ at different doses in obese and non-obese rats.  Materials and methods Thirty-six Wistar albino rats of either sex were divided into obese and non-obese rats equally. Further, rats in both categories were divided into three dosing groups. Group 1 received SB-ITZ 13 mg once daily in the morning, group 2 received SB-ITZ 13 mg in the morning and 6.5 mg in the evening, while Group 3 rats received SB-ITZ 13 mg twice daily, orally. Concentrations of SB-ITZ in the skin, serum, and fatty tissue were assessed in each group on days 7, 14, 21, and 28. Comparison of SB-ITZ concentrations in various tissues in obese and non-obese rats and inter-group comparison of tissue concentrations across the three dosing regimens was done at day 28 and expressed as Mean ± SD.36 Wistar rats were divided into obese and non-obese rats equally. Results At day 28, skin concentrations of SB-ITZ were 5.36±1.1, 8.9±1.7 and 10.13±1.7 µg/g in Groups 1, 2, and 3, respectively, in non-obese rats, which was statistically significant (p<0.05) than skin concentration of obese rats (2.72±0.6, 4.2±0.7 and 4.66±0.5 µg/g) for the corresponding dosing groups respectively. Skin concentration of SB-ITZ was statistically significant for Groups 2 and 3 as compared to Group 1. Still, no statistically significant difference was noted between Groups 2 and 3 in non-obese and obese rats. Fatty tissue concentration of SB-ITZ was comparable in all 3 dosing regimens in non-obese and obese rats. But on the intergroup comparison, a statistically significant difference was observed for Groups 2 and 3 against Group 1 (p<0.05). Increasing the dose of SB-ITZ increased serum concentration. In non-obese rats, a statistically significant difference was noted between Group 2 (74.33±6.6 ng/ml) and Group 1 (52.5±9.9 ng/ml); p<0.01 and also in Group 3 (81.33±6.8 ng/ml) against Group 1; p<0.01. Group 3 achieved significantly higher concentration than the other two groups in obese rats (Group 3; 72±5.3, Group 2; 60.5±4.3, and Group 1; 45±7 ng/ml; p<0.01). Conclusion Overall, skin, fatty tissue, and serum concentrations of SB-ITZ were higher in non-obese rats compared to obese rats in all three dosing groups. Moreover, skin and fatty tissue concentrations were proportionately higher than serum in all the groups in non-obese and obese rats. Though the skin concentration of non-obese rats was significantly higher than obese rats, skin concentration in obese rats was within the minimum inhibitory concentration (MIC) range, demonstrating the efficacy of all dosing regimens.

Effect of Serum Perampanel Concentration on Sporadic Amyotrophic Lateral Sclerosis Progression

BACKGROUND AND PURPOSE

To clarify the effect of perampanel (PER) on sporadic amyotrophic lateral sclerosis (sALS) progression, the relationship between the changes in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) scores and serum PER concentrations was investigated.

METHODS

12 patients with sALS from our hospital who agreed to participate and completed the PER for sALS randomized phase 2 study were included. After completing the study, we retrospectively obtained serum PER concentration data from the patients. Based on their mean PER concentrations, we divided the patients who had been taking PER into two groups: four patients with a mean PER concentration of ≥400 ng/mL were assigned to the H group, and three with a mean PER concentration of <400 ng/mL were assigned to the L group. The control group consisted of five patients who had been taking a placebo. We obtained the ALSFRS-R scores of each patient at 36 and 48 weeks after randomization. The differences in ALSFRS-R scores at baseline (0 weeks) and each subsequent week were used in the analysis.

RESULTS

At 48 weeks, there were no differences in the degree of deterioration of the bulbar, upper and lower limb, and respiratory ALSFRS-R subscores and total ALSFRS-R score. However, at 36 weeks, the bulbar subscore was significantly lower in the H group than in the control group (p=0.032).

CONCLUSIONS

Because high PER concentrations may exacerbate bulbar symptoms in patients with sALS, serum PER measurements may be beneficial when patients with sALS are taking PER.

Status of TWEAK DNA methylation and mRNA expression in systemic lupus erythematosus

OBJECTIVE

Draw upon research into the serum concentration, mRNA expression, and DNA methylation of TNF-like weak inducer of apoptosis (TWEAK) in the peripheral blood of systemic lupus erythematosus patients and healthy controls in an attempt to investigate the epigenetics associated with TWEAK in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

A total of 178 SLE patients (SLE group) and 131 sex-age matched healthy controls (HC group) were recruited. Enzyme-linked immunosorbent assays (ELISA) was used to detect serum protein concentration of TWEAK. TWEAK mRNA expression was analyzed by Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Methylation levels of the promotor of TWEAK were measured using quantitative DNA methylation analysis on the MassARRAY spectrometry.

RESULTS

Serum TWEAK concentrations were not statistically significant in SLE patients and HCs. Nevertheless, serum TWEAK concentrations were significantly lower in patients with renal involvement when compared to those without it. Serum TWEAK concentrations were reduced in clinically active patients (SLEDAI ≥ 10) compared with clinically stable patients (SLEDAI < 10). It was also significantly associated with SLEDAI. Compared with the HC group, the TWEAK mRNA expression in the SLE group was significantly lower. The global DNA methylation levels of TWEAK in the SLE group were observed to be significantly higher than the HC group. SLE patients with renal involvement, and the clinically active patients had higher TWEAK global methylation as well as exhibited variation in certain CpG island methylation. Furthermore, TWEAK methylation negatively correlated with TWEAK mRNA expression.

CONCLUSION

This study suggests that TWEAK DNA methylation is a valuable as a focus for epigenetic studies because of it potentially influencing TWEAK gene expression in SLE patients. Aberrant DNA methylation of TWEAK may be involved in the initiation and development of SLE.

Association between vitamin A and asthma: A meta-analysis with trial sequential analysis

Objective: To explore the association between vitamin A (vit A) status and risk of asthma. Methods: PubMed, Web of Science, Embase and the Cochrane Library were electronically searched to identify related studies that reported the association between vit A status and asthma. All databases were searched from inception to November 2022. Two reviewers independently screened literature, extracted data, and assessed risk bias of included studies. Meta-analysis was performed on R software Version 4.1.2 and STATA Version 12.0. Results: A total of 19 observational studies were included. A pooled analysis showed that the serum vit A concentrations in patients with asthma was lower than that in healthy controls (standard mean difference (SMD)= -2.479, 95% confidence interval (CI): -3.719, -.239, 95% prediction interval (PI): -7.510, 2.552), and relatively higher vit A intake in pregnancy was associated with an increased risk of asthma at age 7 years (risk ratio (RR)= 1.181, 95% CI: 1.048, 1.331). No significant correlation was observed between serum vit A levels or vit A intake and the risk of asthma. Conclusion: Our meta-analysis confirms that serum vit A levels are lower in patients with asthma than in healthy controls. Relatively higher vit A intake during pregnancy is associated with an increased risk of asthma at age 7 years. There is no significant correlation between vit A intake and asthma risk in children, nor between serum vit A levels and asthma risk. The effect of vit A may depend on age or developmental stage, diet and genetics. Therefore, further studies are needed to explore the association of vit A and asthma. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/CRD42022358930, identifier CRD42022358930.

Pharmacokinetic and clinical comparison of super-bioavailable itraconazole and conventional itraconazole at different dosing in dermatophytosis

Background

Due to changing face of dermatophytosis in India, many dermatologists practice different dosing patterns of itraconazole (ITZ). Recently, a new form of ITZ, super-bioavailable ITZ (SBITZ), has been commercialized to overcome the pharmacokinetic challenges of conventional ITZ (CITZ). Serum and sebum concentration of ITZ plays an important role in the management of dermatophytosis. Hence, the current study compares the rate and extent of serum and sebum concentration of SBITZ and CITZ at different dosing to determine their efficacy and safety in patients with dermatophytosis.

Methods

This was an open-label, randomized, four-arm study including 40 adult patients diagnosed with glabrous tinea who were randomized equally into four groups to receive either CITZ-100-BD or CITZ-200-OD (2×100 mg capsules) or SBITZ-130-OD or SBITZ-100-OD (2×SBITZ-50 mg capsules) for 4 weeks. Serum and sebum samples were analysed at different time intervals along with clinical efficacy and safety.

Results

For serum concentration, on day 28, the arithmetic mean and standard deviation (SD) for CITZ-100-BD, CITZ-200-OD, SB-130-OD and SB100-OD were 1262±233.5 ng/mL, 1704±261.6 ng/mL, 1770±268.9 ng/mL and 1520±231.7 ng/mL, respectively, which was statistically significant for OD dosing of ITZ/SBITZ over CITZ-100-BD. Similarly, for sebum concentration, the arithmetic mean and SD for CITZ-100-BD, CITZ-200-OD, SB-130-OD and SB-100-OD were 1042±163.45 ng/mg, 1423±192.46 ng/mg, 1534±227.55 ng/mg and 1107±182.35 ng/mg, respectively, which was statistically significant for SB-130-OD and CITZ-200-OD over CITZ-100-BD and SBITZ-100-OD dosing. No significant difference was noted between SBITZ-130 and CITZ-200 (p=0.25). Only two patients achieved complete cure in the SBITZ-130 group, whereas no patients achieved the same in other groups (p=0.47). All the dosages were very well tolerated with only 12 adverse events reported by ten patients in all groups.

Conclusion

All formulations achieved desired serum and sebum concentrations required for efficacy in dermatophytosis, but SB 130 mg OD and CITZ 200 mg OD were statistically significant than other ITZ doses in achieving sebum concentration. Additionally, SBITZ 130 mg OD was bioequivalent to CITZ 200 mg OD and achieved similar results to those of CITZ 200 mg OD but at 35% lower drug concentrations.

[Therapeutic drug monitoring of antipsychotic drugs in routine psychiatric practice]

OBJECTIVE

To evaluate the relationship between daily doses of antipsychotic drugs, their serum concentrations, and characteristics of patients treated for schizophrenia or schizophreniform disorder in day-to-day clinical practice.

MATERIAL AND METHODS

A total of 187 patients were included in the study, 77 (41.1%) patients were on monotherapy, and 110 (58.9%) patients received two or more antipsychotics. Patients age was 27.8±8.1 years, and their body weight was 79.8±15.6 kg. The sample was represented mainly by young men (93.0%). The proportion of smokers was 37.4%. The appropriate HPLC-MS/MS method was used for the simultaneous analysis of 8 antipsychotics and its active metabolites. Serum concentrations of the drugs aripiprazole (ARI), chlorpromazine (CPZ), haloperidol (HAL), zuclopenthixol (ZUC), clozapine (CLO), risperidone (RIS), quetiapine (QUE), olanzapine (OLA), norclozapine (N-desmethylclozapine, NOR), 9-hydroxyrisperidone (9-OH-RIS), dehydroaripiprazole (DGA) were measured. The serum concentration/dose ratio (C/D) was employed as the primary outcome measure, as doses were not kept constant during the study. The active antipsychotic fraction (drug+active metabolite, active moiety - AM) was also evaluated for RIS and ARI. In addition, the metabolite/parent ratio (MPR) was evaluated for RIS and ARI.

RESULTS

A total of 265 biological samples were obtained, 421 and 203 measurements of the concentration of drugs and their metabolites were carried out, respectively. Overall, 48% of antipsychotics levels were in the expected therapeutic ranges, 30% were below therapeutic ranges, and 22% were above them. A total of 55 patients underwent dose adjustments or drug changes due to ineffectiveness or side-effects. It has been found that smoking reduces the level of C/D for CLO (p<0.01, Mann-Whitney test). We have established that comedication with CLO significantly increases the C/D ratio of QUE (p<0.05, Mann-Whitney test). We have not revealed any influence of weight and age of the subjects on the C/D. The dose-concentration regression relationships are formalized for all AP.

CONCLUSION

Therapeutical drug monitoring (TDM) is an essential tool to personalize antipsychotic therapy. Careful analysis of TDM data can contribute significantly to the study of the impact of individual patient characteristics on systemic exposure to these drugs.

Does China's competitive generic substitution policy deliver equivalent clinical outcomes? A pilot study with two generic formulations of olanzepine

With the National Centralized Drug Procurement policy gradually applied nationally in China, concerns about the effectiveness and safety of bid-winning generic drugs are growing again, but relevant studies are lacking. This real-world, before-and-after study was conducted to explore the clinical effects of switching between two versions of generic olanzapine (one of them was bid-winning product). Pre-and post-switching serum olanzapine concentrations were compared. A total of 30 patients were included and results showed the log-transformed, dose-adjusted concentration of bid-winning generic olanzapine was significantly lower than that of another generic olanzapine, while no significant differences were shown on Clinical Global Impressions Severity of Illness or Improvement ratings before and after switching. This study suggest that a generic version of a psychotropic medication may not be of therapeutic equivalence or bioequivalence with another generic one. Changes in efficacy or tolerability are possible in every switch. Therapeutic drug monitoring could be a valuable tool during switches between generic drugs. Larger prospective clinical studies for other generic psychotropic medications in target populations are warranted.

Quantification of Vitamin D at Different Levels of Clinical Worsening of COVID-19

INTRODUCTION AND AIM

Vitamin D is the name given to a group of lipid-soluble steroidal substances of physiological importance in the body, especially in bone metabolism. The active form of vitamin D is believed to have immunomodulatory effects on immune system cells, especially T lymphocytes, as well as on the production and action of several cytokines and on the expression of potent antimicrobial peptides in epithelial cells that line the respiratory tract, playing an important role in protecting the lung from infections. The aim of this study was to assess vitamin D levels in patients with COVID-19 in healthcare service and to verify that these levels are adequate to protect the progression of this infection.

METHODS

The aim of this observational study was to evaluate the serum concentration of vitamin D in 300 patients suspected of being infected with COVID-19, treated at Basic Health Units (BHUs) and at the Hospital Complex in the municipality of São Bernardo do Campo.

RESULTS

294 patients were included, 195 (66%) of which tested positive for COVID-19 and 99 (34%) negative for COVID-19. Among the patients in the positive group, 163 patients were in the mild group (84%); 22 patients in the moderate group (11%); 8 patients in the severe group (4%), and 2 patients in the deceased group (1%).

CONCLUSION

For the patients in this study, no association was observed for the protective factor of vitamin D against COVID-19 infection, and its role in controlling the clinical staging of the disease was not verified.

[Decreased Serum Copper Concentrations by Zinc Administration in Preterm Infants with Hypozincemia Are Associated with a Lower Postmenstrual Age: A Single-center Retrospective Observational Study]

Copper is one of the essential trace elements in humans, and its deficiency causes various diseases. Zinc acetate dihydrate is administered to treat hypozincemia in preterm infants; however, zinc inhibits the gastrointestinal absorption of copper, which may cause copper deficiency. To safely treat hypozincemia in preterm infants, we retrospectively analyzed the factors reducing serum copper concentrations when zinc is administered to preterm infants with hypozincemia. Seventy preterm infants were included in the present study. Serum zinc and copper concentrations, doses, and other clinical characteristics were retrieved from electronic medical records. The administration of zinc acetate dihydrate decreased serum copper concentrations in 21 out of 70 patients. In comparisons between the two groups with and without a decrease in serum copper concentrations, significant differences were observed in postmenstrual age (34.9 and 35.9 weeks, respectively) and serum zinc concentrations (62.0 and 58.0 μg/dL, respectively) at the start of the zinc acetate dihydrate treatment. A logistic regression analysis identified postmenstrual age as a significant factor decreasing serum copper concentrations. In the ROC curve, the cut-off value for postmenstrual age for a decrease in serum copper concentrations was 34.143 weeks. The present results suggest that when zinc acetate dihydrate is administered to preterm infants with a low postmenstrual age who are at higher risk of decreased serum copper concentrations, particularly to those with a postmenstrual age <34 weeks, it is important to consider copper deficiency and periodically measure serum copper concentrations.

Serum concentration as a predictor of tigecycline-induced hypofibrinogenemia in critically ill patients: a retrospective cohort study

OBJECTIVES

The objective of this study was to determine the thresholds of serum concentration as a predictor of tigecycline-induced hypofibrinogenemia in critically ill patients.

METHODS

A retrospective cohort study was conducted in ICU patients treated with tigecycline. The clinical data and serum concentration were extracted from the patients' electronic medical records. Patients were divided into hypofibrinogenemia (HF) group and normal group according to fibrinogen (FIB) value. The receiver operating characteristic (ROC) curves and logistic regression was used to derive serum concentration thresholds and quantify the association between exposure thresholds and hypofibrinogenemia while adjusting for confounders.

RESULTS

In total, 100 patients were included. ROC curves analyse showed that tigecycline concentration parameters were strongly predictive of hypofibrinogenemia. Adjusting for duration of tigecycline, C_1/2 ≥ 0.645 mg/L, AUC_0-24 ≥ 20.76 mg∙h/L and C_min ≥ 0.455mg/L were associated with a 3- to 5-fold increased risk of tigecycline-induced hypofibrinogenemia in logistic regression.

CONCLUSION

The findings from this study provide evidence that tigecycline exposure is highly predictive of hypofibrinogenemia, with approximately 3- to 5-fold increased risk. C_1/2 ≥ 0.645 mg/L with best area under ROC curve and NPV appears to be the most appropriate toxicity threshold.

Pharmacokinetics and Adverse Effects of Clofazimine in the Treatment of Pulmonary Non-Tuberculous Mycobacterial Infection

Clofazimine (CFZ) is used to treat pulmonary non-tuberculous mycobacterial (NTM) infection; however, its pharmacokinetics remain unexplored in patients with pulmonary NTM, and the relationship between CFZ serum concentration and adverse effects has not been investigated. The objectives of this study were to characterize the pharmacokinetics of CFZ in pulmonary NTM disease treatment and to investigate the relationship between the steady-state CFZ serum concentration and adverse effects. A prospective observational study was conducted on 45 patients with pulmonary NTM treated with CFZ (UMIN000041053). A maximum of five serum samples per patient were taken at the CFZ trough, and serum concentration was measured using high-performance liquid chromatography-mass spectrometry (HPLC-MS). The pharmacokinetics of CFZ were analyzed using a nonlinear mixed effect model. The relationships among steady-state CFZ serum concentration and adverse effects, pigmentation, and heart rate-corrected QT (QTc) interval were investigated. Twenty-six patients had M. avium or M. intracellulare infection and nineteen had M. abscessus infection. The primary CFZ dosage was 50 mg/day. The estimated apparent CFZ clearance, apparent volume of distribution, and half-life were 2.4 L/h, 2,960 L, and 36 days, respectively. The combined use of rifampicin and CFZ significantly reduced CFZ exposure by 22%. Although there was no relationship between CFZ serum concentration and pigmentation intensity, the QTc interval was significantly correlated with CFZ serum concentration. The estimation of accurate pharmacokinetics for CFZ required approximately 5 months of monitoring. The relationship between the serum concentration and specific adverse effects of CFZ confirmed that CFZ serum concentration was not associated with pigmentation but did affect the QTc interval.

Olanzapine poisoning in patients treated at the National Poison Control Centre in Belgrade, Serbia in 2017 and 2018: a brief review of serum concentrations and clinical symptoms

Olanzapine is a thienobenzodiazepine class antipsychotic that strongly antagonises the 5-HT2A serotonin receptor, but acute poisonings are reported rarely. Symptoms of an overdose include disorder of consciousness, hypersalivation, myosis, and coma. Serum concentration higher than 0.1 mg/L is toxic, while concentration above 1 mg/L can be fatal. Here we report key data about 61 patients admitted to the National Poison Control Centre in Belgrade, Serbia over olanzapine poisoning in 2017 and 2018. The ingested doses ranged from 35 to 1680 mg, and time from ingestion to determination from two to 24 hours. In 34 patients olanzapine serum concentrations were in the therapeutic range and in 27 in the toxic range. In five patients they were higher than fatal, but only one patient died. The most common symptoms of poisoning were depressed consciousness (fluctuating from somnolence to coma), tachycardia, hypersalivation, hypotension, myosis, and high creatine kinase. All patients but one recovered fully after nonspecific detoxification and symptomatic and supportive therapy.

Development and application of a novel LC-MS-MS method for human plasma concentration monitoring of perampanel in pediatric epilepsy patients

This study has developed and validated a novel LC-MS/MS assay method to quantify perampanel in pediatric patients with epilepsy in Xinjiang, China. Our assay reduces current specimen volume requirements, and decreases the turnaround time for results. Samples were separated by gradient elution and then injected into the mass spectrometer with a total run-time of 3 min per sample. Detection of ions from the analytes was conducted using multiple reactions by monitoring transitions of m/z 350.2-m/z 219.0 for perampanel and m/z 359.1-m/z 323.1 for IS, as precursor ion and product one, respectively. The peak area ratios of perampanel with IS within the plasma samples were linear in the concentration range of 0.1-3.2 μg/mL (y = 2.87 x + 0.61; r ² ≥ 0.99). The within-run and between-run precision coefficient of variation (CV (%) did not exceed 11.03%, and the accuracy (bias) ranged from -1.07% to 6.69%. The mean absolute recoveries of perampanel for four QC levels (including LLOQ, LQC, MQC and HQC) determined by this method were 87.69%, 94.04%, 107.50% and 95.15%, respectively. The stability results for this method showed that the plasma samples of perampanel were stable under all tested conditions (86.43-104.81%), with % CV maximum of 8.74%.

Maternal and fetal serum concentrations of magnesium after administration of a 6-g bolus dose of magnesium sulfate (MgSO4 ) to women with imminent preterm delivery

INTRODUCTION

Magnesium sulfate is used world-wide to treat pregnant women at imminent risk of preterm delivery in order to protect the brain of the premature infant. Previous research has shown that magnesium sulfate decreases the risk of cerebral palsy by ~30% in infants born preterm. Despite this, the dosage required for optimal neuroprotection remains unknown. We aimed to investigate whether 6 g magnesium sulfate given as a single bolus dose was tolerable for the women and infants and whether the desired target concentration in the mother's blood was reached and non-toxic level in the infant could be ensured.

MATERIAL AND METHODS

In total, 49 women who were at risk of delivery prior to 32 weeks of gestation were recruited. They received a bolus dose of 6 g magnesium sulfate intravenously between 1 and 24 h prior to giving birth and were closely monitored during and after infusion. Blood samples from the patients were analyzed at different time-points (20-30 min after start of infusion, 1, 2, 6 and 24 h) post-administration. Blood samples from the umbilical cord were also taken directly after birth to assess the concentration of magnesium in the infant.

RESULTS

None of the women who received magnesium sulfate reached serum magnesium concentrations >3.3 mmol/L. In all, 72% of the women showed serum magnesium levels within the therapeutic interval (2.0-3.5 mmol/L) and no adverse events were observed during the infusion. The serum magnesium levels in the mothers declined to pre-bolus-levels within 24 h after delivery. Serum magnesium levels in the umbilical cord samples ranged from 0.87 to 1.4 mmol/L, which means that all but two were within the normal expected range for a newborn premature infant.

CONCLUSIONS

A bolus dose of 6 g magnesium sulfate was well tolerated and without any serious side effects in either mother or infant. Most of our women reached the targeted concentration range of serum magnesium levels after infusion was completed. Their infants had magnesium levels within acceptable levels, regardless of gestational week or mother's body mass index.

VEGFA Haplotype and VEGF-A and VEGF-R2 Protein Associations with Exudative Age-Related Macular Degeneration

Our study aimed to reveal the associations between VEGFA SNPs (rs1570360, rs699947, rs3025033, and rs2146323), their haplotypes, VEGF-A and VEGF-R2 serum concentrations, and early and exudative AMD. A total of 339 subjects with early AMD and 419 with exudative AMD groups, and 374 healthy subjects, were genotyped for four VEGFA SNPs (rs1570360, rs699947, rs3025033, and rs2146323). VEGF-A and VEGFR-2 serum concentrations were measured in exudative AMD and controls. The results revealed that rs3025033 G allele was significantly associated with lower odds of exudative AMD under the dominant model (OR = 0.67; 95% CI: 0.49–0.80; p = 0.0088) and additive (OR = 0.7; 95% CI: 0.54–0.90; p = 0.0058) models after Bonferroni correction. In the female group, rs3025033 AG genotype was associated with exudative AMD under the codominant model (OR = 0.57; 95% CI: 0.37–0.87; p = 0.009) and G allele under the dominant (OR = 0.55; 95% CI: 0.37–0.82; p = 0.0032) and additive models (OR = 0.60; 95% CI: 0.42–0.84; p = 0.0028). Haplotype analysis revealed that individuals carrying rs1570360, rs699947, rs3025033, and rs2146323 haplotype A-A-G-A had decreased risk of exudative AMD (OR = 0.46, 95% CI: 0.23–0.90; p = 0.023). The VEGF-A and VEGF-R2 serum concentrations did not differ between study groups; we found that patients with exudative AMD carrying at least one C allele at rs699947 have statistically significantly higher VEGF-A serum concentrations compared to AA genotype carriers (485.95 (945.93) vs. 194.97 (-), respectively, p = 0.046). In conclusion, we found that VEGFA rs3025033 and haplotype rs1570360A-rs699947A-rs3025033G- rs2146323A play a protective role for exudative AMD in the Caucasian population. Furthermore, rs699947 is associated with elevated VEGF-A serum concentrations in exudative AMD.

Antidepressant efficacy is correlated with plasma levels: mega-analysis and further evidence

The debate around optimal target dose for first-line antidepressants (ADs) is still ongoing. Along this line, therapeutic drug monitoring (TDM) represents one of the most promising tools to improve clinical outcome. Nevertheless, a few data exist regarding the concentration-effect relationship of first-line ADs which limits TDM implementation in routine clinical practice. We conducted the first patient-level concentration-response mega-analysis including data acquired by us previously and explored the concentration dependency of first-line AD (206 subjects). Further, new data on mirtazapine are reported (18 subjects). Hamilton Depression Rating Scale-21 administered at baseline, at month 1 and month 3 was used as the measure of efficacy to assess antidepressant response (AR). When pooling all four first-line ADs together, normalized plasma levels and AR significantly fit a bell-shaped quadratic function with a progressive increase of AR up to around the upper normalized limit of the therapeutic reference range with a decrease of AR at higher serum levels. Our results complement the available evidence on the issue and the recent insights gained from dose-response studies. A concentration-dependent clinical efficacy, such as previously demonstrated for tricyclic compounds, also emerge for first-line ADs. Our study supports a role for TDM as a tool to optimize AD treatment to obtain maximum benefit.

Venlafaxine and O-desmethylvenlafaxine serum levels are positively associated with antidepressant response in elder depressed out-patients

BACKGROUND

Therapeutic Drug Monitoring (TDM) represents one of the most promising tools in clinical practice to optimise antidepressant treatment. Nevertheless, little is still known regarding the relationship between clinical efficacy and serum concentration of venlafaxine (VEN). The aim of our study was to investigate the association between serum concentration of venlafaxine + O-desmethylvenlafaxine (SCVO) and antidepressant response (AR).

METHODS

52 depressed outpatients treated with VEN were recruited and followed in a naturalistic setting for three months. Hamilton Depression Rating Scale-21 was administered at baseline, at month 1 and at month 3 to assess AR. SCVO was measured at steady state. Linear regression analysis and nonlinear least-squares regression were used to estimate association between SCVO and AR.

RESULTS

Our results showed an association between AR and SCVO that follows a bell-shaped quadratic function with a progressive increase of AR within the therapeutic reference range of SCVO (i.e. 100-400 ng/mL) and a subsequent decrease of AR at higher serum levels.

DISCUSSION

This study strongly suggests that TDM could represent a more appropriate tool than the oral dosage to optimise the treatment with VEN. Specifically, highest efficacy might be achieved by titrating patients at SCVO levels around 400 ng/mL.

Relationship between Serum Bortezomib Concentration and Emergence of Diarrhea in Patients with Multiple Myeloma and/or AL Amyloidosis

(1) Background: multiple myeloma patients have benefited from bortezomib therapy, though it has often been discontinued owing to diarrhea. The objective of this study was to verify serum bortezomib concentration in the emergence of diarrhea. (2) Methods: this prospective, observational case-control, and monocentric study was performed with an approval by the Ethics Committee of Kumamoto University Hospital in 2015 (No. 1121) from February 2015 to April 2017. (3) Results: twenty-four patients with bortezomib therapy were recruited; eight patients (33.3%) developed diarrhea at day 3 as median. Median measured trough bortezomib concentration at 24 h after first or second dose for patients with or without diarrhea was 0.87 or 0.48 ng/mL, respectively (p = 0.04, Wilcoxon signed rank test). Receiver operation characteristic (ROC) analysis produced the cut-off concentration of 0.857 ng/mL (area under the ROC curve of 0.797, sensitivity of 0.625, specificity of 0.875). The survival curves between patients with and without diarrhea were similar (p = 0.667); those between patients with higher and lower concentration than median value (0.61 ng/mL) were also similar (p = 0.940). (4) Conclusions: this study indicated the possible involvement of serum bortezomib concentration in the emergence of diarrhea in bortezomib therapy in patients with multiple myeloma.

Interaction between valproic acid and carbapenems: decreased plasma concentration of valproic acid and liver injury

BACKGROUND

Several case reports and retrospective studies have indicated that carbapenems decrease the plasma concentration of valproic acid (VPA). This retrospective study examines the effect of carbapenems on VPA levels, and explores whether the drug-drug interaction can influence the liver function of patients.

METHODS

The data of 141 patients were collected from the Department of Neurosurgery at Shanxi Bethune Hospital from January 2018 to December 2019. We compared the VPA levels between the VPA monotherapy group and VPA + carbapenem group to evaluate the influence of carbapenem antibiotics on the plasma concentration of VPA. We also compared the liver injury rate of the VPA monotherapy group, VPA + meropenem group, and VPA + imipenem group to evaluate the influence of concomitant use of VPA with carbapenem antibiotics on liver function.

RESULTS

The VPA serum concentration in the VPA + meropenem group was 22.32±21.77 µg/mL, which was markedly lower than that in the VPA monotherapy group (i.e., without carbapenems) (65.17±21.49 µg/mL) (P<0.01). The rate of liver injury was significantly different between the VPA monotherapy, VPA + meropenem, and VPA + imipenem groups (χ2=30.13, P<0.01). Further comparisons showed that the liver injury rate of the VPA + meropenem group (35.42%) was higher than that of the VPA + imipenem (3.7%) and VPA monotherapy (1.52%) groups (P<0.01). Although no significant differences in liver injury rate were observed between the VPA + imipenem (3.7%) and VPA monotherapy (1.52%) groups, the alanine aminotransferase (ALT) value of the VPA + imipenem group after co-administration (65.22±48.01 U/L) was notably higher than before (40.48±24.97 U/L) (P<0.01).

CONCLUSIONS

In this study, the interaction between VPA and carbapenems resulted in decreased plasma concentrations of VPA as well as possible liver injury. Clinicians should be aware of this potential interaction, and closely monitor VPA concentrations and liver function. Different carbapenems combined with VPA showed different effects on both VPA concentration and liver function, indicating that the mechanisms of these two effects might be related.

[Paradoxical effect of levetiracetam on seizure suppression: three cases showing U curve association between dose and effect]

We experienced 3 adult patients with intractable focal epilepsy treated by levetiracetam (LEV) as polytherapy, who showed paradoxical effect (PE). Starting dose of LEV was small (62.5, 250 mg/day) and we gradually increased by less than 250 mg/day, every more than 2 weeks. Within 6 months after LEV was added, LEV of 750 to 1,000 mg/day brought reduction of seizure frequency. Serum concentration of LEV was 13.3 and 14.0 μg/ml. In order to obtain better seizure control, LEV was increased up to 1,000-2,500 mg/day (19.3-35.0 μg/ml) within one year, and they developed PE. They all showed increased habitual seizures, occurring in cluster. Once dose of LEV deceased down to what produced the maximum seizure suppression, all of the patients regained the better seizure control. It is most likely that at least in some patients like present 3 cases, PE of LEV may express U curve association between dose and effect and that it was only delineated by slow titration.

Influence of switching from intravenous to oral administration on serum voriconazole concentration

WHAT IS KNOWN AND OBJECTIVE

While bioavailability of oral voriconazole is known to be >90%, several reports have observed much lower oral bioavailability. The aim of the present study was to assess the oral bioavailability of voriconazole in clinical use by evaluating the change in serum voriconazole concentration in patients who received intravenous-to-oral switch therapy with the same dose of voriconazole.

METHODS

A single-centre, retrospective cohort study was conducted at the 614-bed Gifu University Hospital in Japan. Patients who received intravenous-to-oral switch therapy with the same dose of voriconazole between 1 January 2011 and 31 December 2018 were enrolled in the present study. We evaluated changes in serum voriconazole concentration before and after switch therapy.

RESULTS

Voriconazole trough concentrations significantly decreased following oral compared to intravenous treatment (2.5 ± 1.5 µg/mL vs 3.3 ± 2.0 µg/mL, p = 0.021). The median change rate of serum concentration by switching the route of administration was 82.7%, with wide inter-individual variability (range 27.2-333.3%). Further, concomitant glucocorticoid administration was a significant protective factor for reducing serum concentration (OR 0.16, 95% CI 0.03-0.79, p = 0.025).

WHAT IS NEW AND CONCLUSION

Switching from intravenous to oral treatment resulted in a significant decline in voriconazole trough concentrations with wide inter-individual variability. Therefore, measurement of serum concentration for dose adjustment should be performed after switching to the oral form.

Early Serum Infliximab Levels in Pediatric Ulcerative Colitis

Background: Data on serum infliximab concentrations during induction in pediatric ulcerative colitis are limited. The study aim is to evaluate the relationship between serum infliximab concentrations during induction and short-term clinical remission in children with ulcerative colitis. Methods: We carried out a prospective, multi-center cohort study in pediatric patients with ulcerative colitis. Serum infliximab concentrations were collected at peak dose #1, week 1, trough pre-dose #2, and trough pre-dose #3. Infliximab dosing was left to investigator discretion. Clinical remission was defined by pediatric ulcerative colitis activity index <10 at week 8. Results: Twenty-four of thirty-four subjects (71%) achieved clinical remission at week 8. The median infliximab concentrations were 33.0 μg/mL (interquartile range: 26.5-52.1 μg/mL) pre-dose #2 and 22.5 μg/mL (interquartile range:15.9-32.3 μg/mL) pre-dose #3. Trough pre-dose #2 infliximab concentration yielded area under receiver operator characteristic curve 0.7, 95% CI: 0.5-0.9 in predicting week 8 clinical remission; a cut-off of 33.0 μg/mL yielded 62.5% sensitivity, 66.7% specificity. Trough pre-dose #3 infliximab concentrations were lower for subjects <10 years compared to ≥ 10 years [median 15.9 μg/mL, interquartile range (IQR) 8.5-21.8 μg/mL vs. 27.7 μg/mL, IQR 17.2-46.7 μg/mL, p = 0.01] and correlated with baseline weight (Spearman's rank correlation coefficient 0.45, p = 0.01). The median half-life following first IFX dose was 6.04 days (IQR 5.3-7.9 days). Conclusions: Infliximab concentrations ≥33 μg/mL prior to the second dose were associated with week 8 clinical remission. As young age and low body weight impact infliximab concentration, prospective studies with proactive adjustment in pediatric patients with ulcerative colitis should be carried out. Clinicians caring for children with UC should diligently adjust and monitor infliximab to optimize response.

Development and validation of an innovative UPLC method to quantify lacosamide, oxcarbazepine, and lamotrigine in the serum of children with epilepsy in China

This study has developed and validated a novel UPLC method to quantify lacosamide (LCM), oxcarbazepine (OXC), and lamotrigine (LTG) in children with epilepsy in Xinjiang, China. Phenytoin sodium was used as the internal standard. The mobile phase contained ammonium dihydrogen phosphate solution (10 mmol/L, pH = 4.0) and methanol (55:45, v/v). The flow rate, injection volume, column temperature, and detection wavelength were 0.2 mL/min, 2 μL, 30°C, and 240 nm, respectively. The method was linear within 0.5-40, 2.5-80, and 2.5-40 μg/mL for LCM, 10-hydroxycarbazepine (MHD), and LTG, respectively (r²  ≥ 0.998). The intra- and inter-day precision as measured by the relative standard deviation values was between 1.36 and 4.50, 0.54 and 1.91, and 0.58 and 1.56%. Recovery ranged from 96.58 to 106.22%. All serum samples could be maintained for up to 3 h at ambient temperature, 24 h at 4°C, 30 days at -30°C, and after successive freeze-thaw cycles (24 h per cycle) in the absence of significant degradation.

[The Effect of Increased Free Concentrations of Warfarin Due to Protein-binding Substitution in a Combination of Tolvaptan on the PT-INR]

We previously reported that tolvaptan may influence warfarin pharmacodynamics in vivo; however, the mechanism responsible for this influence was not clear. In this study, we investigated the drug-drug interactions between warfarin and tolvaptan by measuring warfarin blood concentrations in 18 patients who received warfarin therapy and in 24 who received warfarin+tolvaptan therapy. The free warfarin concentrations significantly increased in patients who were also receiving oral tolvaptan (p=0.04). In vitro albumin-binding experiments showed that the free warfarin concentrations significantly increased with the addition of tolvaptan, in a dose-dependent manner, through albumin-binding substitution (approximately 2.5 times). Both clinical and in vitro data showed that tolvaptan increased the unbound warfarin serum concentration. The prothrombin time-international normalized ratio (PT-INR) tended to increase within 2 weeks when tolvaptan was added at clinically used doses (p=0.14). Special attention is warranted in cases with a serum tolvaptan concentration of ≥125 ng/mL (≥7.5 mg/d) for at least 2 weeks following oral tolvaptan administration.

Higher venlafaxine serum concentrations necessary for clinical improvement? Time to re-evaluate the therapeutic reference range of venlafaxine

BACKGROUND

The therapeutic reference range for venlafaxine in antidepressant treatment has been defined as 100 to 400 ng/mL. However, in an everyday setting active moiety concentrations above the therapeutic reference range were often reported.

AIM

The aim of this study was to re-evaluate the therapeutic reference range of venlafaxine.

METHODS

In-patients (⩽60 years) with major depressive episodes receiving antidepressant monotherapy with venlafaxine during routine clinical treatment were included in this observational study. Depressive symptom severity was evaluated on a weekly basis using the Hamilton Depression Rating Scale (HAMD-21), and therapeutic drug monitoring analyses were performed. Resting electrocardiograms were analyzed in week 3, week 5 and week 7 of study participation.

RESULTS

Clinical improvement from baseline to week 4 was significantly associated with increasing serum concentrations of the active moiety of venlafaxine (N = 23, Pearson correlation, p = 0.009), but not with the dose of venlafaxine. Patients achieving remission showed significantly higher serum concentrations than patients achieving response/non-response (Kruskal-Wallis test, p = 0.019). Moreover, in patients with serum concentrations above 400 ng/mL time to remission and time to response was significantly shorter than in patients with concentrations below 400 ng/mL (Mantel-COX test, p = 0.001; p = 0.010). QTc time was below the upper limit of a normal QTc time (450 ms) for all patients.

CONCLUSION

The serum concentration of the active moiety and not the dose determined the effect of venlafaxine. Shorter remission times without ECG alterations in patients with serum concentrations above the therapeutic reference range suggest a re-evaluation of the therapeutic reference range for venlafaxine in larger studies.

Higher Serum C-Reactive Protein Levels in Catatonic Patients: A Comparison to Non-catatonic Patients and Healthy Controls

Catatonia is a psychomotor syndrome defined by a constellation of predominantly motor symptoms. The aim of the present study was to determine whether recently admitted psychiatric patients with catatonia exhibited higher serum C-reactive protein (hs-CRP) levels compared to non-catatonic psychiatric patients and healthy controls (HCs). Recently admitted psychiatric patients were screened and evaluated for the catatonia syndrome using the Bush-Francis Catatonia Rating Scale and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). The study sample was formed by 150 individuals (39 male and 111 female), including 51 catatonic patients, 55 non-catatonic patients, and 44 HCs. Serum hs-CRP levels were processed with the enzyme-linked immunosorbent assay. Serum levels of creatine kinase (CK), adrenocorticotropic hormone (ACTH), immunoglobulin G (IgG), complement component 3 (C3), and complement component 4 (C4) were also determined. There was a significantly higher percentage of patients with high inflammatory levels (hs-CRP > 3000ng/ml) in the catatonic (43.1%) than in the non-catatonic (14.5%) or HCs group (9.1%) (χ 2 =18.9, P < .001). Logistic regression showed that catatonic patients had significantly higher hs-CRP levels compared to non-catatonic patients even after controlling for other clinical and laboratory variables (OR = 3.52, P = .015, 95% CI 1.28-9.79). Multiple linear regression analysis revealed that log-transformed hs-CRP was independently predicted by body mass index and log-transformed C4, ACTH, and Cortisol in catatonic patients. Findings of the present study suggest that catatonia is specifically linked to a higher level of systemic inflammation, not merely attributable to the overall psychopathology, or alterations in the stress level and complement system.

Comparison of early pregnancy serum concentration of neopterin, neopterin/creatinine ratio, C-reactive protein, and chitotriosidase, in pregnant women with birth at term and spontaneous preterm birth

Inflammatory mechanisms are involved in achieving a normal pregnancy and in the development of certain pregnancy complications. These changes are more intense in pregnant women that suffer of pregnancy complications, such as spontaneous preterm birth (SPB). This study compared the course of inflammatory markers (IM) [neopterin (Neo), neopterin/creatinine ratio (Neo/Cre), C-reactive protein (CRP), and chitotriosidase (Chito)] serum concentration in the early pregnancy of women with birth at term (BT) and preterm birth (PB). IM concentration was measured in 90 sera sampled from 45 pregnancies with BT and 30 sera from 15 pregnancies with PB. Two sera were sampled from each pregnant woman: one in the first trimester and another one in the second trimester. Early pregnancy IM concentration showed a direct correlation with gestational age: Neo (rho=0.262, P=0.004), Neo/Cre (rho=0.372, P<0.001), CRP (rho=0.187, P=0.041), and Chito (rho=0.039, P=0.66). The correlation was present in both categories of patients with BT and PB. Patients with PB before 34 week of pregnancy (wp) and 32 wp showed higher Neo and Neo/Cre concentration than BT patients. A significant association was found between the risk of PB before 34 wp, PB before 32 wp, and Neo concentration (PB <34 wp: odds ratio (OR) =5.13, P=0.035) (PB <32 wp: OR=8.2, P=0.020) and, respectively, Neo/Cre concentration (PB <34 wp: OR=5.29, P=0.015) (PB <32 wp: OR=9.25, P=0.006). No association between CRP or Chito and PB age was found. IM concentration correlates with the gestational age at the time of blood sampling. Increased Neo and Neo/Cre concentration are associated with PB. Further studies are needed to evaluate the usefulness of these markers in clinical practice.

Serum Concentrations of Cholinesterase Inhibitors in Patients With Alzheimer's Dementia Are Frequently Below the Recommended Levels

Background

Acetylcholinesterase inhibitors (AChE-I) are recommended for the treatment of cognitive symptoms but also of behavioral and psychological symptoms in dementia. They are widely used not only in Alzheimer's disease, but also in other forms of dementia. Efficacy of treatment might depend on serum concentration of the respective AChE-I.

Objective

In patients with mild to moderate Alzheimer's dementia, we measured serum concentrations of hepatically metabolized donepezil and renally excreted rivastigmine and investigated possible modifiers. Additionally, we looked at correlations between serum concentrations and efficacy for both drugs.

Methods

Serum concentrations of donepezil and rivastigmine were measured by liquid chromatography – tandem mass spectrometry (LC-MS/MS). Real-time quantitative polymerase chain reaction (PCR). Allele specific PCR were performed to determine CYP2D6 genotype and gene dose. Clinical efficacy was assessed by changes of the subtest wordlist delayed recall of the Consortium to Establish a Registry for Alzheimer's Disease-Neuropsychological Assessment Battery (CERAD-NAB).

Results

Sixty-seven patients treated with a stable dosage of donepezil 10 mg (n=41) or rivastigmine 9.5 mg (n=26) were included. Mean serum concentration of donepezil and rivastigmine were 41.2 and 6.5 ng/ml, respectively. Serum concentrations were below the recommended range in 73% of the subjects in the donepezil group and in 65% of the participants in the rivastigmine group. When applying a dose-related reference, ranges 63% of patients in the donepezil group and 32% in the rivastigmine group had concentrations below the expected range. Gene dose, sex, and duration of treatment significantly predicted donepezil serum concentration (p=0.046, p=0.001, p=0.030 respectively). Only for rivastigmine did the serum concentration significantly contribute to the regression model predicting changes on the subtest word list delayed recall (β=0.472; p=0.019).

Conclusions

Serum concentrations of about two thirds of the patients were below the recommended range. When not looking at absolute values but at the dose-related reference ranges, these numbers improved but still 32%, respectively 63% of patients had low serum concentrations. High serum concentrations of rivastigmine predicted clinical response to cognition. Therapeutic drug monitoring might help to identify the cause of poor clinical response to cognition and behavioral and psychological symptoms in patients with AChE-I treatment.

Genetic polymorphisms of transient receptor potential melastatin 1 correlate with voriconazole-related visual adverse events

BACKGROUND

Causes of voriconazole-related visual adverse events (VVAE) remained controversial.

OBJECTIVES

We aimed to explore the relationship between voriconazole serum concentrations and VVAE as well as the potential influence of transient receptor potential melastatin 1 (TRPM1) on VVAE.

PATIENTS/METHODS

This prospective observational cohort study was done in two stages. Patients who received voriconazole for invasive fungal diseases were consecutively enrolled. Correlations between voriconazole trough levels and VVAE were explored in 76 patients. Genotyping was further conducted for 17 tag SNPs of TRPM1 in a larger population of 137 patients. Genotype distributions were compared between patients with and without VVAE.

RESULT

Of the 76 patients, a total of 229 steady-state voriconazole trough levels were evaluated, 69.9% of which were within the target range (1-5.5 mg/L). No correlations were found between voriconazole trough levels and VVAE. Of the total 137 patients, VVAE occurred in 37 (27.0%) patients, including visual hallucination (13.9%, 19/137) and visual disturbances (19.0%, 26/137). Significant difference in TRPM1 genotype distribution was only observed in patients with visual hallucination but not with visual disturbances. We found that rs890160 G/T genotype was under-presented (OR, 0.11; 95% CI, 0.01-0.84; P = .011) and rs1378847 C/C genotype was more frequently detected (OR, 8.89; 95% CI, 1.14-69.02; P = .013) in patients with visual hallucination when compared with those without.

CONCLUSION

Transient receptor potential melastatin 1 was genetically associated with voriconazole-related visual hallucination. The correlation was failed to found between voriconazole trough levels and VVAE.

The Role of Serum Lithium Concentration on Pill Burden in Psychiatric Populations

Objective: Current research validates the use of lithium as a first-line agent in bipolar disorder, yet it remains underutilized. This might, in part, be the result of lithium's risk of toxicity. A lower serum lithium concentration would decrease the risk of toxicity. This study examined whether lithium serum concentrations are associated with an additional medication burden resulting from psychiatric polypharmacy. Methods: The retrospective data of adult inpatients receiving lithium who had at least one serum lithium concentration recorded were extracted from the computerized patient record system, bar code medication administration, and mental health automated health record system. Results: 38 patient charts were reviewed and a total of 192 individual serum lithium concentrations were analyzed. There was no statistically significant difference (increase or decrease) in the number of psychiatric medications prescribed or the number of scheduled psychiatric medication doses administered. There was a statistically significant increase in the number of psychiatric medications prescribed over the Food and Drug Administration (FDA) recommended maximum daily dose (MDD) following a serum lithium concentration record. Individuals with a serum lithium concentration below 0.6mEq/L were more likely to be prescribed medications over the MDD. Conclusion: Serum lithium concentrations did not increase or decrease the overall psychiatric pill burden. The number of psychiatric medications an individual is prescribed remained the same regardless of their serum lithium concentration. Overall pill burden did not change with the serum lithium concentration; however, lower serum lithium concentrations might necessitate prescribing of psychiatric medications in doses exceeding the MDD.

[Biomarkers of vitamin status in obese school children]

Inadequate intake of vitamins, noted in children with obesity, reduces the immune system activity, contributes to the metabolic disorders aggravation and may result in comorbidity. The aim of the work was to study sufficiency with vitamins and carotenoids of children with obesity. Material and methods. Examination of vitamin D, B₂, C, A, E and β-carotene status in 50 children (male 36.0%) aged 11-17 years [median (Me) - 14 years] with obesity [Z-score body mass index (BMI) >=2.0, Ме=2.86] by determining serum biomarkers has been conducted. Results and discussion. All of the children had an adequate supply with vitamin C (ascorbic acid level >0.4 mg/dL). Low vitamin A status (retinol <30 μg/dl) was revealed in 8% children. Deficiency of vitamin D [25(OH)D<20 ng/ml], vitamin B₂ (riboflavin <5 ng/ml) and β-carotene (<10 μg/dl) was detected in 62.0, 38.8 and 74.0% of obese children. The percentage of persons with reduced vitamin E serum level (<0.8 mg/dl) was amounted 54.0%. A severe vitamin D deficit (<10 ng/ml) has been detected in 24.0% of children with Z-score BMI >=2.86 (median value) and has not been observed in children with lower body weight, whose serum β-carotene median was 1.5 fold higher (p<0.05). No one was adequately supplied with all 5 studied vitamins and β-carotene. The combined deficiency of 3 or more vitamins took place in 54.0% of obese children. Synchronously suboptimal serum level of ascorbic acid (<50 μmol/l), β-carotene (<0.4 μmol/l) and α-tocopherol/cholesterol ratio (<5.0 μmol/mmol) which is a cardiovascular disease risk factor, has been found in 28.0% of children. BMI was inversely associated with 25(OH)D serum concentration (ρ=-0.313, р=0.027). There was a pronounced negative correlation between serum level of β-carotene and atherogenic LDL cholesterol (ρ=-0.514, p<0.001). Conclusion. The prevalence of combined vitamin D, tocopherol and carotenoids' inadequacy in obese children indicates the importance of vitamin status correction to reduce the risk of metabolic syndrome.

Pharmacokinetic interaction between modified Atkins diet and antiepileptic drugs in adults with drug-resistant epilepsy

OBJECTIVE

The aim was to examine the influence of modified Atkins diet on serum concentration of antiepileptic drugs (AEDs).

METHODS

Prospective data from 63 adult patients with either focal or generalized drug-resistant epilepsy recruited to 12-week dietary treatment as add-on to AEDs are analyzed. AED serum concentrations, ketones, glucose, and hemoglobin A1c were measured before and after the dietary intervention. Paired t test was used and Spearman correlation coefficient, r, was estimated.

RESULTS

Mean age was 37 years (range 16-65 years). Mean serum concentrations of carbamazepine, clobazam, and valproate were significantly reduced after 4 and 12 weeks of the diet period (<.001 ≤ P ≤ .02). Levels of lacosamide, lamotrigine, and topiramate were less reduced (.02 ≤ P ≤ .08), whereas the serum concentrations of oxcarbazepine, zonisamide, and levetiracetam were unchanged (.06 ≤ P ≤ .90). The largest reduction in serum concentration was found for clobazam: mean reduction after 12 weeks was 1.5 μmol/L (34%). Percent change in serum concentration after 4 and 12 weeks of all drugs analyzed was -10.5% (95% confidence interval [CI] -14.1 to -6.8; n = 60; P < .001) and -13.5% (95% CI -18.8 to -8.3; n = 56; P < .001), respectively. Percent change in serum concentration of AEDs was not significantly correlated to percent change in seizure frequency after 12 weeks of dietary treatment (r = .14, P = .33, n = 53) but negatively correlated to urine ketosis (r = -.43; P = .003; n = 46).

SIGNIFICANCE

A reduction in AED serum concentrations may counteract a seizure-reducing effect of the diet, and in patients without such an effect, it may cause seizure aggravation. Thus, we recommend that clinicians who are treating patients with ketogenic diets monitor serum concentrations of the concomitant AEDs.

Validation of a Weight Threshold-Based Vancomycin Dosing Protocol for Patients Undergoing Intermittent Hemodialysis

BACKGROUND

Patients receiving intermittent hemodialysis (IHD) are at high risk of acquiring gram-positive infections, which are often treated with IV vancomycin. Despite frequent use of vancomycin in the IHD setting, there is variability in dosing and monitoring practices among clinicians at the study institution. There is also a paucity of evidence regarding optimal vancomycin dosing to achieve target pre-IHD serum concentration.

OBJECTIVES

The primary objective was to compare the percentage of treatment courses with a serum vancomycin concentration between 15 and 20 mg/L, measured before the third IHD session, before and after implementation of a weight threshold-based dosing protocol. The secondary objectives were to compare the percentage of treatment courses with a pre-third IHD vancomycin concentration between 10 and 22 mg/L and the number of vancomycin measurements per treatment day, before and after protocol implementation.

METHODS

This quasi-experimental, single-centre study included inpatients and outpatients who underwent IHD and received at least 2 IV doses of vancomycin, with vancomycin being measured in an appropriately drawn sample before the third IHD session. Before protocol implementation, vancomycin dosing was at the clinician's discretion (usual care). After protocol implementation, each patient received a loading dose of 1000, 1500, or 2000 mg and a maintenance dose of 500, 750, or 1000 mg, depending on body weight.

RESULTS

The percentage of treatment courses with a pre-third IHD vancomycin concentration between 15 and 20 mg/L was greater after implementation of the protocol than with usual care, but the difference was nonsignificant (44% [8/18] versus 20% [3/15], p = 0.27). However, the percentage of treatment courses with a pre-third IHD vancomycin concentration between 10 and 22 mg/L was significantly higher after protocol implementation (94% [17/18] versus 53% [8/15], p = 0.012). There was no difference in the median number of vancomycin measurements per treatment day before and after protocol implementation (0.133 versus 0.125, p = 0.99).

CONCLUSIONS

At the study institution, the likelihood of achieving recommended vancomycin concentration increased (relative to previous practice) after implementation of a simplified vancomycin dosing protocol for patients undergoing IHD.

Serum Concentrations of Interferon Gamma (IFN-γ) in Patients with Psoriasis: Correlation with Clinical Type and Severity of the Disease

Introduction:

The etiopathogenesis of psoriasis is still unclear but there is evidence that many of cytokines released by keratinocytes and inflammatory leukocytes may contribute to the induction or persistence of the inflammatory process in psoriasis.

Aim:

The aim of the study was to evaluate serum concentrations of Interferon gamma (IFN-γ) in patients with psoriasis and the healthy subjects and also to assess a possible association between IFN-γ, clinical type and severity of disease.

Material and Methods:

The study included a total of 60 patients with psoriasis and 20 healthy subjects in the control group. According to the clinical type of disease, patients with psoriasis were divided into four groups: psoriasis vulgaris (PV), psoriasis erythrodermica (PE), psoriasis pustulosa (PP) and psoriasis arthropatica (PA). Blood samples were collected from all psoriasis patients and from healthy control subjects. Serum IFN-γ levels were measured by an enzyme-linked immunosorbent assay (ELISA) technique. The severity of PV was assessed by Psoriasis Area and Severity Index (PASI) score.

Results:

The serum concentration of IFN-γ in patients with psoriasis was significantly higher than that in the control group (1.91±1.79 pg/mL vs 0.91±0.38 pg/mL, respectively). Significantly elevated serum IFN-γ concentrations were noticed in patients with PV (2.15±0.30 pg/mL). There was no statistically significant difference between the mean values of IFN- γ compared to the clinical type of psoriasis (p>0.05). In the group of patients with PV 36 (85.71%) patients had mild form of disease with PASI <50, and 6 (14.29%) patients had severe disease with PASI >50. It was not found statistically significant correlation between serum IFN-γ level and PASI score in the group of PV.

Conclusions:

The results of our study indicate that psoriasis is associated with significant changes in the serum concentration of IFN-γ. There was no significant correlation between serum IFN-γ concentrations, clinical type of psoriasis and severity of PV evaluated with the use of PASI score.

Quinidine therapy and therapeutic drug monitoring in four patients with KCNT1 mutations

Several recent studies have reported potassium sodium-activated channel subfamily T member 1 (KCNT1) mutations in epilepsy patients on quinidine therapy. The efficacy and safety of quinidine for epilepsy treatment, however, remains controversial. We herein report the cases of four patients with KCNT1 mutations treated with quinidine. A reduction in seizures of more than 50% after quinidine treatment was observed in one patient with epilepsy of infancy with migrating focal seizures (EIMFS), whereas two patients with EIMFS and one with focal epilepsy did not achieve apparent seizure reduction. The relationship between quinidine dose and serum quinidine concentration was inconsistent, particularly at high quinidine doses. One patient with EIMFS developed ventricular tachycardia the day after an increase in quinidine dose from 114 to 126 mg/kg/day. The serum trough quinidine concentration and the corrected QT interval (QTc) before arrhythmia onset were 2.4 μg/ml and 420 ms, respectively, and peak serum quinidine concentration after arrhythmia onset was 9.4 μg/ml. Another patient with EIMFS showed aberrant intraventricular conduction with a quinidine dose of 74.5 mg/kg/day and a serum trough concentration of 3.2 μg/ml. Given that serum quinidine levels may elevate sharply after a dose increase, careful monitoring of electrocardiographs and serum concentrations is required. Based on a review of previous reports and our experience with this case, quinidine should be considered as a promising drug for patients with EIMFS harbouring KCNT1 mutations, however, its efficacy remains controversial due to the limited number of cases, and more information on optimal serum concentrations and appropriate titration methods is required.

Role of Nephronectin in Pathophysiology of Silicosis

Silicosis is a typical form of pneumoconiosis and is characterized as a type of lung fibrosis. Silica particles are captured and recognized upon by alveolar macrophages via the macrophage receptor with collagenous structure (MARCO) scavenger receptor, and thereafter the inflammasome is activated. Thereafter, various chemokines/cytokines play their roles to eventually form fibrosis. Additionally, silica particles chronically activate T helper cells which sets the background for the formation of silicosis-associated autoimmune disturbances. The occurrence and progression of lung fibrosis, the extracellular matrix-related molecules such as integrins and their ligands including fibronectin, vitronectin, laminin, and collagens, all play important roles. Here, the roles of these molecules in silicosis-related lung fibrosis are reviewed from the literature. Additionally, the measurement of serum nephronectin (Npnt), a new member of the integrin family of ligands, is discussed, together with investigations attempting to delineate the role of Npnt in silica-induced lung fibrosis. Serum Npnt was found to be higher in silicosis patients compared to healthy volunteers and seems to play a role in the progression of fibrosis with other cytokines. Therefore, serum Npnt levels may be employed as a suitable marker to monitor the progression of fibrosis in silicosis patients.

Rapid attainment of target trough concentrations of tacrolimus for early improvement of clinical symptoms in patients with ulcerative colitis

WHAT IS KNOWN AND OBJECTIVE

The target trough concentration of tacrolimus for ulcerative colitis is recommended to be 10-15 ng/mL in the initial two weeks and 5-10 ng/mL in the later phase. However, the effectiveness of rapid attainment of these target trough concentrations of tacrolimus in patients with ulcerative colitis is still unclear. In the present study, we evaluated the clinical efficacy and safety of rapid attainment of target trough concentrations of tacrolimus in patients with ulcerative colitis.

METHODS

A prospective cohort was conducted at Gifu University Hospital in Gifu, Japan. Hospitalized patients who received tacrolimus for the treatment of ulcerative colitis between April 2009 and March 2017 were enrolled. Since June 2011, the initial loading dose of tacrolimus increased from 0.05 to 0.1-0.2 mg/kg/d, and the maintenance dose to achieve the target trough concentration was determined to be 12.5 ng/mL by proportional calculation with measured blood concentration. The period required to attain target trough concentration and the clinical efficacy before and after dosage modification was compared.

RESULTS

The initial dose after dosage modification was significantly increased compared to that before dosage modification (0.10 [0.04-0.22], median [range] mg/kg/d vs 0.05 [0.03-0.05] mg/kg/d, P < 0.001). The period required to attain a target trough concentration over 10 ng/mL was significantly shortened by dosage modification (6 [4-14] days before dosage modification vs 4.5 [2-8] days after modification, P = 0.048). Further, stool frequency score was significantly improved after dosage modification, without affecting the incidence of adverse events.

WHAT IS NEW AND CONCLUSION

Our findings suggest that rapid attainment of the target trough concentration of tacrolimus improves clinical symptoms in patients with ulcerative colitis.

Impact of teicoplanin maintenance dose and MIC values on the clinical outcomes of patients treated for methicillin-resistant Staphylococcus aureus bacteremia

Objectives

Teicoplanin, a glycopeptide, is regarded as among the drug choices for methicillin-resistant Staphylococcus aureus (MRSA) infections. Few studies have evaluated the relationship between teicoplanin minimal inhibitory concentrations (MICs) and outcomes among patients with serious MRSA infections.

Subjects and methods

We investigated the relationship between teicoplanin maintenance dose and clinical outcomes, on the completion of teicoplanin therapy, in bacteremia patients with MRSA infection, with different teicoplanin MICs. A total of 146 adult patients with MRSA bacteremia were enrolled at Kaohsiung Chang Gung Memorial Hospital between September 2012 and September 2015.

Results

A higher number of patients in the high-dose regimen group (6 mg/kg/12 h) had favorable outcomes than those in the standard-dose regimen group (6 mg/kg/24 h) (84.1% vs 41.2%; p<0.01), regardless of the teicoplanin MICs. In the multivariate analysis, a Pittsburgh bacteremia score ≥4 (OR, 0.07, 95% CI, 0.03–0.19) was a risk factor for an unfavorable final clinical response, whereas high-dose teicoplanin maintenance therapy for MRSA bacteremia was significantly associated with a favorable final response (OR, 25.3 [95% CI, 4.43–144.03] for isolates with a teicoplanin MIC ≥1.5 mg/L and OR, 5.6 [95% CI, 1.57–19.91] for isolates with a teicoplanin MIC <1.5 mg/L). Survival at 30 days was significantly better for patients receiving high-dose teicoplanin maintenance treatment, regardless of the teicoplanin MICs of the MRSA isolates. Patients were selected using propensity score matching, based on the independent predictors of a favorable final outcome. After appropriate propensity score matching, patients in the high-dose regimen group still had a statistically significant favorable outcome at the end of treatment (84.1% vs 40.9%; p<0.01).

Conclusion

The results suggested that high-dose teicoplanin maintenance treatment is associated with more favorable outcomes than standard-dose teicoplanin maintenance treatment, for patients with MRSA bacteremia, regardless of the teicoplanin MIC.

Enteral administration of protein supplement and valproate: A potential pharmacokinetic interaction

Background

Valproic acid (VPA) and its derivatives are highly protein bound. Certain highly protein bound medications (eg, phenytoin) have specific administration instructions for patients on enteral nutrition supplements to optimize absorption of the medication. Pharmacokinetic interactions between VPA and enteral nutrition or protein supplements demonstrating impaired absorption have not been published to date.

Case Report

A patient receiving enteral VPA syrup via percutaneous endoscopic gastrostomy tube experienced a clinically significant decrease in serum concentration when enteral protein supplement was initiated. Other sources of interactions were ruled out, and VPA serum concentration increased when doses were separated from protein supplement by 2 hours.

Discussion

This is the first published case of enteral protein supplementation affecting absorption of enteral VPA. Enteral feeds are known to interact with other highly protein bound medications, and clinical practice for these medications may be used to guide administration when an interaction with VPA is suspected.

Conclusion

When using enteral protein supplements concomitantly with enteral VPA, clinicians may consider separating doses to avoid potential interaction or impaired absorption.

Reference ranges for antiepileptic drugs revisited: a practical approach to establish national guidelines

BACKGROUND AND OBJECTIVE

Laboratories sometimes use different reference ranges for the same antiepileptic drug (AED), particularly for new and poorly investigated drugs. This may contribute to misunderstandings, concerns or inappropriate dose changes, which in turn may affect therapeutic effect, drug safety or treatment adherence. Therefore, the Norwegian Association of Clinical Pharmacology wished to update and harmonize the reference ranges for AEDs and establish national guidelines for Norway.

METHODS

A working group collected information on the reference ranges used by Norwegian laboratories for all commonly used AEDs. These reference ranges were compared to recent recommendations by the International League Against Epilepsy, current literature, applicable clinical studies, reference ranges used by leading Northern European epilepsy centers outside of Norway, and routine data derived from Norwegian laboratory databases.

RESULTS

Reference ranges varied between laboratories for four of 23 available AEDs (lamotrigine, valproate, eslicarbazepine and oxcarbazepine). For four AEDs (brivaracetam, perampanel, stiripentol and sulthiame), reference ranges had not previously been established. In total, 13 reference ranges were either harmonized, updated or newly established. No changes were applied to the remaining 10 AEDs.

CONCLUSION

Updated and harmonized reference ranges are now available for 22 of the 23 AEDs available in Norway. The exception is vigabatrin (reference range not applicable). Revision of reference ranges is an important part of pharmacovigilance of AEDs and must be a continuous process based on current literature and clinical experience.

Riluzole Serum Concentration in Pediatric Patients Treated for Obsessive-Compulsive Disorder

PURPOSE/BACKGROUND

The goals of this study were to determine whether pediatric serum concentration of riluzole is similar to that observed in adults and to determine whether riluzole serum concentration is associated with adverse effects or efficacy in children and adolescents with treatment-refractory obsessive-compulsive disorder.

METHODS/PROCEDURES

Data were drawn from previously published studies: 1 open-label trial and 1 randomized controlled trial with an open-label extension phase. Serum was drawn at 24, 36, and 52 weeks in 37 patients who were taking approximately 100 mg riluzole daily (mean dose at 24 weeks, 99 ± 28 mg).

FINDINGS/RESULTS

Across all samples, serum riluzole concentration ranged from 7 to 963 ng/mL. At week 24 (n = 37), the median concentration was 76 ng/mL (interquartile range, 53-172 ng/mL). Within-patient concentration was relatively stable. One subject who had the highest serum concentration levels during the study developed pancreatitis after exiting the study. The patient had recently added fluvoxamine to the riluzole regimen. Controlling for concomitant fluvoxamine (in 6 participants) and time of draw, serum riluzole concentration was not associated with obsessive-compulsive disorder symptom severity, nor was it associated with adverse effect profile.

IMPLICATIONS/CONCLUSIONS

The dose of riluzole used in these pediatric subjects seems to have achieved serum concentration levels similar to those observed in adults. However, as previously reported in adults, the serum concentration had no discernable relationship to efficacy or adverse effects.

Serum Concentration of Erlotinib and its Correlation with Outcome and Toxicity in Patients with Advanced-stage NSCLC

BACKGROUND

Erlotinib is a tyrosine kinase inhibitor targeting epidermal growth factor receptor (EGFR); it is used in the treatment of advanced non-small cell lung cancer (NSCLC). We focused on the role of serum concentration of erlotinib and its association with outcome and toxicity in patients with advanced NSCLC harbouring the wild-type EGFR gene or squamous histology.

PATIENTS AND METHODS

Clinical data of 122 patients were analyzed. Serum samples were collected within four weeks after the initiation of treatment.

RESULTS

There was no significant association of erlotinib concentration with PFS nor OS (p=0.352 and p=0.6393). Significant associations of erlotinib concentration with grade of skin rash and diarrhoea (p<0.0001 and p<0.0001) were found. Skin rash and diarrhoea were significantly associated with PFS (p=0.0338 and p=0.0001) and OS (p=0.0064 and p=0.0353).

CONCLUSION

Erlotinib concentration was not associated with outcome. Erlotinib concentration was associated with occurrence and severity of skin rash and diarrhoea; the outcome was associated with erlotinib toxicity.

IGF1 gene polymorphisms associated with diabetic retinopathy risk in Chinese Han population

Objective

This study aimed to explore the association of insulin-like growth factor 1 gene (IGF1) polymorphisms with diabetic retinopathy (DR) in a Chinese Han population.

Methods

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping. Genotype frequencies were compared by chi-square test. Odds ratio (OR) with 95% confidence interval (95%CI) was calculated to express the risk intensity of DR. Linkage disequilibrium between IGF1 polymorphisms was analyzed by Haploview. Serum IGF1 concentration was measured by enzyme-linked immunosorbent assays (ELISA) and assessed by student's t test.

Results

AG genotype of rs6218 and TT genotype of rs35767 were significantly associated with the elevated risk of DR (rs6218: OR=1.77, P=0.04; rs35767: OR=2.32, P=0.03) and type II diabetes mellitus (T2DM) (rs6218: OR=1.92, P=0.00. rs35767: OR=2.29, P=0.02). Only T allele of rs35767 significantly increased the risk of DR (OR=1.45, P=0.04), however, rs6218 (OR=1.92, P=0.00), rs35767 (OR=0.02, P=0.02) and rs5742612 (OR=2.21, P=0.04) showed obvious association with T2DM. Haplotypes were only associated with T2DM, but not DR. Minor allele homozygote of rs35767 was obviously correlated with serum IGF1 level.

Conclusion

IGF1 rs6218 and rs35767 polymorphisms contribute to the risk of DR. IGF1 rs35767 polymorphism may participate in the regulation of serum IGF1 concentration in DR.

Effect of human autologous serum and fetal bovine serum on human corneal epithelial cell viability, migration and proliferation in vitro

AIM

To analyze the concentration-dependent effects of autologous serum (AS) and fetal bovine serum (FBS) on human corneal epithelial cell (HCEC) viability, migration and proliferation.

METHODS

AS was prepared from 13 patients with non-healing epithelial defects Dulbecco's modified eagle medium/Ham's F12 (DMEM/F12) with 5% FBS, 0.5% dimethyl sulphoxide (DMSO), 10 ng/mL human epidermal growth factor, 1% insulin-transferrin-selenium, then were incubated in serum media: DMEM/F12 supplemented by 5%, 10%, 15% or 30% AS or FBS. HCEC viability was analyzed using cell proliferation kit XTT, migration using a wound healing assay, proliferation by the cell proliferation enzyme-linked immunosorbent assay (ELISA) BrdU kit. Statistical analysis was performed using the generalized linear model, the values at 30% AS or 30% FBS were used as the baselines.

RESULTS

HCEC viability was the highest at 30% AS or 15% FBS and the lowest at 10% AS or 30% FBS application. HCEC migration was the quickest through 30% AS or 30% FBS and the slowest through 5% AS or 5% FBS concentrations. Proliferation was the most increased through 15% AS or 5% FBS and the least increased through 30% AS or 30% FBS concentrations. HCEC viability at 10% and 15% AS was significantly worse (P=0.001, P=0.023) compared to baseline and significantly better at 15% FBS (P=0.003) concentrations. HCEC migration was significantly worse (P≤0.007) and HCEC proliferation significantly better (P<0.001) in all concentration groups compared to baseline.

CONCLUSION

For the best viability of HCEC 30% AS or 15% FBS, for HCEC migration 30% AS or 30% FBS, for proliferation 15% AS or 5% FBS should be used. Therefore, we suggest the use of 30% AS in clinical practice.

Concentration of Sulfate and Glucuronide Conjugates of Ritodrine in Twin Pregnancy

Ritodrine, a drug for the treatment of threatened premature labor, is a highly selective beta-2 agonist with the major metabolites of sulfate and glucuronide conjugates. This study investigated the continuous evaluation of the concentration of ritodrine conjugates in relation to the clinical course in twin pregnancy. The subjects were 9 twin-pregnancy mothers who delivered after receiving ritodrine treatment between April 2012 and December 2013. Serum ritodrine sulfate and glucuronide conjugates were deconjugated using their specific enzymes. Ritodrine concentration was measured by liquid chromatography-tandem mass spectrometry. The continuous infusion rate of ritodrine was 2.66±0.67 (0.8-3.54) µg/min/kg, and the average concentration of unchanged ritodrine was 118.8±33.2 (63.8-194.0) ng/mL. During the study period between week 32 and week 36 of gestation, the average ratio of unchanged ritodrine concentration and sulfate ritodrine conjugate concentration for weeks 32, 33, 34, 35, and 36 were 1.7, 1.9, 1.5, 1.7, and 1.7 not significant (N.S.), respectively. The average ratio of unchanged ritodrine concentration and glucuronide ritodrine conjugate concentration were 1.8, 2.2, 1.9, 1.8, and 2.1 (N.S.), respectively. No statistical difference was identified in the ratios of unchanged ritodrine concentration and sulfate or glucuronide ritodrine conjugate concentrations. Large individual differences were shown in the concentration of sulfate and glucuronide during the gestational period. No change in the ratio of the formation of ritodrine metabolites was identified as the gestational age progressed.

Guidance for the determination of status indicators and dietary requirements for magnesium

Balance data obtained since 1997 indicate that the Estimated Average Requirement and Recommended Dietary Allowance for magnesium should be 175 and 250 mg/d, respectively, for 70 kg healthy individuals, and increase or decrease based on body weight. Urinary excretion data from balance studies indicate that 40 to 80 mg (1.65 to 3.29 mmol) Mg/day are excreted when magnesium intakes are <250 mg/day, and 80 to 160 mg/day (3.29 to 6.58 mmol) when intakes are >250 mg/day. The change in urinary magnesium excretion with the change in dietary magnesium intake occurs within a few days. Thus, urinary magnesium would be most useful for population studies. Metabolic unit depletion/repletion experiments show that serum magnesium concentrations decrease only after a prolonged depletion if an individual starts with an adequate magnesium status. Individuals with serum magnesium concentrations in excess of 0.75 mmol/L (1.82 mg/dL), or as high as 0.85 mmol/L (2.06 mg/dL), might be magnesium-deficient because such individuals respond to magnesium supplementation. A combination of a dietary intake <250 mg /day, urinary excretion <80 mg (3.29 mmol)/day, and serum magnesium concentration < 0.85 mmol/L (2.06 mg/dL) and preferably <0.80 mmol/L (1.94 mg/dL) could indicate that an individual would respond to magnesium supplementation.

Influence of ABCB1 polymorphisms and serum concentrations on venlafaxine response in patients with major depressive disorder

BACKGROUND

The pharmacokinetics and the pharmacodynamics of antidepressants show large inter-individual variations which result in unpredictable clinical responses.

AIM

The aim of the study was to examine the effect of ABCB1 polymorphisms and the serum concentrations on the efficacy and tolerability of venlafaxine in patients with major depressive disorder (MDD).

METHODS

Fifty-two outpatients who met the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) criteria for MDD were recruited for the study. The severity of depression was assessed using the 17-item Hamilton Rating Scale for Depression scale (HDRS₁₇) and tolerability was assessed based on a query regarding side-effects for 6 weeks. The ABCB1 C3435T/A and G2677T/A polymorphisms were genotyped by PCR/RFLP and steady-state serum venlafaxine concentrations were measured by high-performance liquid chromatography.

RESULTS

Patients with the TT genotype for the C3435T and the TT/TA genotype for the G2677T/A polymorphism showed significantly higher frequencies in venlafaxine-induced akathisia. This relationship was not observed for efficacy. As regards serum venlafaxine concentrations, patient groups showed no significant differences in efficacy and tolerability.

CONCLUSION

The results suggest that individuals with the TT-TT/TA genotypes for the C3435T-G2677T/A polymorphisms of ABCB1 may be pre-disposed to a risk of akathisia.

Unexplained spikes in lamotrigine serum concentration: nonlinear elimination?

OBJECTIVES

The objective of this study was to evaluate possible nonlinear lamotrigine (LTG) pharmacokinetics at elevated concentration. LTG is reported to have linear kinetics, so that elimination rate is linearly proportional to blood concentration and a change in dose is accompanied by a proportionate change in serum concentration. We encountered patients in whom LTG serum concentration increased dramatically in response to minor or no change in LTG dose. We studied this phenomenon in patients with LTG toxicity in one clinic.

MATERIALS AND METHODS

Using electronic medical records from 1997 to 2014, we identified patients who developed clinical LTG toxicity with LTG serum concentrations >20 mg/l, after tolerating lamotrigine at lower serum concentrations. We reviewed LTG dose change and other changes that preceded the episode of toxicity.

RESULTS

Twenty-two patients had at least one episode of LTG toxicity with levels higher than 20 mg/l (of 922 patients with available levels). The peak serum concentration varied from 21.1 to 40.3 mg/l (mean 28.7). The increase in level was explained in three patients (post-delivery in one, addition of valproate in two). In the 18 others, the increase was not explained or it was disproportionate to an increase in LTG dose.

CONCLUSIONS

Spikes in LTG levels and associated clinical toxicity may occur unexpectedly, suggesting that elimination kinetics may be nonlinear in some individuals at serum concentrations in the upper range. Measurement and close monitoring of LTG levels is warranted for new symptoms that could be consistent with lamotrigine toxicity, particularly when the baseline serum concentration has been >10 mg/l.