Gabapentin for Pain in Pediatric Palliative Care

OBJECTIVE

Gabapentin is commonly used to treat pain in children receiving pediatric palliative care. This study describes the real-world use of gabapentin and the associated benefits and adverse effects/events (AEs).

METHODS

A prospective, multicenter cohort of standardized data collection after a clinical decision was made to use gabapentin for managing neuropathic or nociplastic pain in children attended on by a pediatric palliative care service. It was conducted across 11 sites in seven countries including hospital, inpatient, and outpatient services. Clinical outcomes were graded using pain scales validated for age and cognitive ability and the National Cancer Institute Common Terminology Criteria for Adverse Events (NCICTCAE) at baseline, 14 days, 28 days, six weeks and 12 weeks after initiation of gabapentin. Ad-hoc safety reporting continued throughout the study.

RESULTS

Data were collected from 127 children with a median age of 4.7 years (IQR 0.1-17.9); 61% had a neurological disorder, 21% advanced cancer and the cohort had a high level of disability (Lansky/Karnofsky performance score 37.1). Gabapentin was prescribed at standard pediatric doses. On average, 76% of children had a reduction in pain and 42% experienced a potential AE. The mean pain score decreased from 6.0 (SD 2.6) at baseline to 3.3 (SD 2.4) at 14 days and 1.8 (SD 1.8) after 12-weeks of gabapentin therapy. Ten percent had increased pain at each time point. AEs did not increase when individual changes over time were accounted for except for somnolence (7%). Serious AEs attributable to gabapentin were possible or probable in 3% of children.

CONCLUSIONS

Gabapentin prescribed at standard doses for advanced cancer and severe neurological injury in children under a pediatric palliative care service was associated with generally improved pain intensity at previously described levels of adverse effects.

Gabapentin and oral antidepressants for chronic pruritus: a prospective cohort study evaluating efficacy and side effects in daily dermatological practice

BACKGROUND

Chronic pruritus is frequently seen in daily dermatological practice and is associated with marked impact on quality of life. Research on the use of gabapentin and oral antidepressants in daily dermatological practice is scarce.

OBJECTIVE

To evaluate the efficacy and safety of gabapentin and oral antidepressants in patients with chronic pruritus in daily clinical practice.

METHODS

A prospective observational single-center cohort study was conducted including adult patients with chronic pruritus and an indication for systemic treatment between June 2016 and May 2019.

RESULTS

Systemic treatment with gabapentin and/or antidepressants was initiated in 31 patients with severe chronic pruritus (median average pruritus NRS score 7.0), in which most cases no underlying origin was identified (83.9%). In patients treated with gabapentin 900-1800 mg/day (N = 25), median average pruritus NRS decreased to 5.5 (IQR 3.0) after 4 weeks and remained stable up to 24 weeks of treatment. Efficacy of antidepressants was variable, with the highest response after initiation of amitriptyline, nortriptyline, and mirtazapine. Side effects were frequently observed in both gabapentin and antidepressant treatments; however, were mostly mild and temporary.

LIMITATIONS

This was a single-site observational study, with limited sample size.

CONCLUSION

Treatment with gabapentin and antidepressants should be considered in patients with chronic pruritus unresponsive to conventional treatment.

Abuse and addiction in gabapentinoid drug users for neuropathic pain

OBJECTIVE

Gabapentinoids are gamma-aminobutyric acid analogue agents used in the treatment of neuropathic pain. They are increasingly being abused to achieve euphoric and dissociative effects. This study aimed to determine drug misuse/abuse and related factors in patients who used gabapentinoids for neuropathic pain.

PATIENTS AND METHODS

This study included 140 patients over the age of 18. Patients were excluded from the study if they had aphasia, dementia, or diseases that led to aphasia or cooperative and cognitive dysfunction. They were also excluded if they lacked sufficient information about how long or at what dosage they had been using the drug. The Beck Depression Inventory and Beck Anxiety Inventory were used to evaluate depression and anxiety states. The patients' levels of drug abuse were determined according to the definitions provided in the terminology for misuse, abuse, and related events.

RESULTS

The mean age of the patients was 56.78 ± 14.45 years, and 52.1% of them were females. While 57.9% of the patients used pregabalin, 42.1% of the patients used gabapentin. For the median (min-max) of the dataset, the pregabalin dose was 300 (50-600) mg/day, and the gabapentin dose was 900 (300-2,400) mg/day. Abuse was present in 17.9% of the patients. Risk factors for gabapentinoid abuse were smoking, alcohol, and antidepressant use, anxiety and depression, living alone, and drug dose and duration of use.

CONCLUSIONS

Before prescribing drugs and managing the treatment process in a controlled manner, questioning patients about their risk factors can reduce the rate of abuse.

Heterocyclic Aromatic Amines and Risk of Kidney Stones: A Cross-Sectional Study in US Adults

Background

Heterocyclic aromatic amines (HAAs) are a group of harmful substances produced while cooking meat at high temperatures. This study aimed to investigate the relationship between HAAs and the occurrence of kidney stones.

Methods

Data on the level of four HAAs, including 2-Amino-9H-pyrido [2, 3-b] indole (A-α-C), 1-Methyl-9H-pyrido [3, 4-b] indole (Harman), 9H-Pyrido [3, 4-b] indole (Norharman), and 2-Amino-1-methyl-6-phenylimidazo [4, 5-b] pyridine (PhIP), in the urine from adult participants were extracted from the 2013–2014 NHANES database. Propensity score matching (PSM) was used to balance confounding variables between the stone former and non-stone former groups, and logistic regression analysis was performed to analyze the relationship between HAAs and the occurrence of kidney stones.

Results

Of the 1,558 eligible participants, a history of kidney stones was self-reported by 140 (9.0%). Compared to non-stone formers, stone formers had higher concentrations of A-α-C, Harman, and Norharman and lower concentrations of PhlP in urine. After adjusting for all other confounding variables, multivariate logistic regression analysis showed that the high-Harman group had a higher risk of kidney stones than the low-Harman group [adjusted odds ratios (aOR) = 1.618, 95% CI: 1.076–2.433, p = 0.021]. After PSM analysis, Harman concentration remained a risk factor for kidney stones (high-Harman group vs. low-Harman group: aOR = 1.951, 95% CI: 1.059–3.596, p = 0.032).

Conclusion

Increased urinary Harman concentrations are associated with an increased risk of kidney stones in the general US population.

HAIR DYE-INDUCED RETINOPATHY MIMICKING MEK-INHIBITOR RETINOPATHY

PURPOSE

To report a new toxic retinopathy related to the use of hair dye.

METHODS

Case reports of three patients with follow-up after exposure and until resolution.

RESULTS

There were three middle-aged women (32-66 year old) all of whom had bilateral moderate to severe vision loss and normal slit-lamp examination at presentation. Fundus examination showed bilateral multiple serous retinal detachments predominantly located in the posterior pole, with some pigment epithelial hypertrophy in chronic cases. Optical coherence tomography showed similar features as in MEK-inhibitor retinopathy. Electrooculogram performed in one patient showed abnormal Arden ratio. During follow-up, visual acuity improved with regression of the serous retinal detachments. The speed of resolution was proportional to the acuteness of the exposure to aromatic amines.

CONCLUSION

Hair dyes containing aromatic amines can be responsible for bilateral toxic retinopathy mimicking MEK-inhibitor retinopathy.

Potential Role of Heterocyclic Aromatic Amines in Neurodegeneration

Heterocyclic aromatic amines (HAAs) are mainly formed in the pyrolysis process during high-temperature cooking of meat. Meat consumption is very typical of the western diet, and the amount of meat consumption in the eastern countries is growing rapidly; HAAs represents widespread exposure. HAAs are classified as possible human carcinogens; numerous epidemiological studies have demonstrated regular consumption of meat with HAAs as risk factor for cancers. Specific HAAs have received major attention. For example, 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine has been extensively studied as a genotoxicant and mutagen, with emergent literature on neurotoxicity. Harmane has been extensively studied for a role in essential tremors and potentially Parkinson's disease (PD). Harmane levels have been demonstrated to be elevated in blood and brain in essential tremor patients. Meat consumption has been implicated in the etiology of neurodegenerative diseases; however, the role of toxicants formed during meat preparation has not been studied. Epidemiological studies are currently examining the association between HAAs and risk of neurodegenerative diseases such as essential tremors and PD. Studies from our laboratory and others have provided strong evidence that HAA exposure produces PD and Alzheimer's disease-relevant neurotoxicity in cellular and animal models. In this review, we summarize and critically evaluate previous studies on HAA-induced neurotoxicity and the molecular basis of potential neurotoxic effects of HAAs. The available studies provide strong support for the premise that HAAs may impact neurological function and that addressing gaps in understanding of adverse neurological outcomes is critical to determine whether these compounds are modifiable risk factors.

Is gabapentin a safe and effective treatment for nonneuropathic pain?

ABSTRACT

A review of the recent literature found that compared with placebo or other pain medications, gabapentin did not significantly reduce nonneuropathic pain. The drug also is associated with an increased risk of adverse reactions, including somnolence, dizziness, and nausea. Given the lack of efficacy and risk of adverse reactions, gabapentin should not be used for nonneuropathic pain.

Bioinformatic Analysis Identified Hub Genes Associated with Heterocyclic Amines Induced Cytotoxicity of Peripheral Blood Mononuclear Cells

Heterocyclic amines (HCAs) are a set of food contaminants that may exert a cytotoxic effect on human peripheral blood mononuclear cells (PBMC). However, the genetic mechanism underlying the cytotoxicity of HCAs on PBMC has not been investigated. In the study, bioinformatic analysis on gene dataset GSE19078 was performed. The results of weighted correlation network analysis and linear models for microarray and RNA-seq data analysis showed that four gene modules were relevant to 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) exposure while one gene module was correlated with 2-amino-3-methyl-3H-imidazo[4,5f]quinoline (IQ) exposure. Gene functional analysis showed that the five modules were annotated mainly with mRNA transcriptional regulation, mitochondrial function, RNA catabolic process, protein targeting, and immune function. Five genes, MIER1, NDUFA4, MLL3, CD53 and CSF3 were recognized as the feature genes for each hub gene network of the corresponding gene module, and the expression of feature genes was observed with a significant difference between the PhIP/IQ samples and the other samples. Our results provide novel genes and promising mechanisms for exploration on the genetic mechanism of HCAs on PBMC.

[Hepatotoxicity probably associated with gabapentin]

BACKGROUND

Gabapentin is an anticonvulsant medication used as an adjuvant in the treatment of neuropathic pain; few cases have been reported in which it causes acute liver injury.

CLINICAL CASE

56-year-old male patient with a history of chronic kidney disease on hemodialysis and narrowing of the spinal canal under treatment with gabapentin, who presented acute liver injury probably secondary to a dose of gabapentin; however, it remitted with the suspension of said drug.

CONCLUSION

Gabapentin lacks liver metabolism; the mechanism by which it produces liver injury is still unknown; however, there are reports of hepatotoxicity associated with its administration, so its use must be individualized for each patient.

Gabapentin controlled substance status

Gabapentin is approved to treat postherpetic neuralgia and epilepsy with partial-onset seizures. The large majority of gabapentin prescribing is off label. Gabapentin may be abused for euphoria, potentiating the high from opiates, reduction of alcohol cravings, a cocaine-like high, as well as sedation or sleep. Individuals at the highest risk for abusing gabapentin include those with opioid abuse, mental illness, or previous history of prescription drug abuse. States are now taking action to track gabapentin use through prescription monitoring programs, and some states have reclassified it as a Schedule V controlled substance. This commentary summarizes gabapentin's abuse potential, identifies state-level actions regarding gabapentin monitoring, and discusses possible clinical implications and ways to enhance patient safety when prescribing gabapentin.

Behaviour of Vascular Smooth Muscle Cells on Amine Plasma-Coated Materials with Various Chemical Structures and Morphologies

Amine-coated biodegradable materials based on synthetic polymers have a great potential for tissue remodeling and regeneration because of their excellent processability and bioactivity. In the present study, we have investigated the influence of various chemical compositions of amine plasma polymer (PP) coatings and the influence of the substrate morphology, represented by polystyrene culture dishes and polycaprolactone nanofibers (PCL NFs), on the behavior of vascular smooth muscle cells (VSMCs). Although all amine-PP coatings improved the initial adhesion of VSMCs, 7-day long cultivation revealed a clear preference for the coating containing about 15 at.% of nitrogen (CPA-33). The CPA-33 coating demonstrated the ideal combination of good water stability, a sufficient amine group content, and favorable surface wettability and morphology. The nanostructured morphology of amine-PP-coated PCL NFs successfully slowed the proliferation rate of VSMCs, which is essential in preventing restenosis of vascular replacements in vivo. At the same time, CPA-33-coated PCL NFs supported the continuous proliferation of VSMCs during 7-day long cultivation, with no significant increase in cytokine secretion by RAW 264.7 macrophages. The CPA-33 coating deposited on biodegradable PCL NFs therefore seems to be a promising material for manufacturing small-diameter vascular grafts, which are still lacking on the current market.

Meat intake, meat cooking methods, and meat-derived mutagen exposure and risk of sessile serrated lesions

BACKGROUND

Red and processed meat, recognized carcinogens, are risk factors for colorectal neoplasia, including polyps, the precursor for colorectal cancer. The mechanism is unclear. One possible explanation is the mutagenic activity of these foods, perhaps due to generation during cooking [e.g., heterocyclic amine (HCA) intake]. Few studies have evaluated meat intake and sessile serrated lesion (SSL) risk, a recently recognized precursor, and no study has evaluated meat cooking methods and meat-derived mutagens with SSL risk.

OBJECTIVE

We evaluated intakes of meat, meat cooking methods, and inferred meat mutagens with SSL risk and in comparison to risk of other polyps.

METHODS

Meat, well-done meat, and inferred meat mutagen intakes were evaluated. Polytomous logistic regression models were used to estimate ORs and 95% CIs among cases (556 hyperplastic polyp, 1753 adenoma, and 208 SSL) and controls (3804) in the large colonoscopy-based, case-control study, the Tennessee Colorectal Polyp Study.

RESULTS

The highest quartile intakes of red meat (OR: 2.38; 95% CI: 1.44, 3.93), processed meat (OR: 2.03; 95% CI: 1.30, 3.17), well-done red meat (OR: 2.19; 95% CI: 1.34, 3.60), and the HCA 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX; OR: 2.48; 95% CI: 1.49, 4.16) were associated with increased risk of SSLs in comparison to the lowest quartile intake.

CONCLUSIONS

High intakes of red and processed meats are strongly and especially associated with SSL risk and part of the association may be due to HCA intake. Future studies should evaluate other mechanism(s) and the potential for primary prevention.

Doneness preferences, meat and meat-derived heterocyclic amines intake, and N-acetyltransferase 2 polymorphisms: association with colorectal adenoma in Japanese Brazilians

Intake of heterocyclic amines (HCAs) and other mutagenic compounds formed during cooking has been hypothesized to be responsible for the positive association observed between red meat and colorectal cancer. We evaluated whether well-done/very well-done preferences for various meat and fish items, higher intakes of meat and fish, and meat-derived and fish-derived HCA are associated with the risk of colorectal adenoma (CRA) in a Japanese-Brazilian population. We selected 302 patients with adenoma and 403 control individuals who underwent total colonoscopy between 2007 and 2013, and collected information on aspects of meat intake using a detailed questionnaire. We also estimated HCA intake of the study participants using an HCA database that matched the cooking methods of this population. Latent class analysis on the basis of response to doneness preferences for different cooking methods of commonly consumed meat and fish items identified four distinct subgroups. Compared with the subgroup characterized by a preference for rare/medium well-done cooking for most meat and fish items, the odds ratio of CRA for the well-done/very well-done preference subgroup was 1.19 (95% confidence interval: 0.51-2.75). High intake of mixed-meat dishes was suggestively associated inversely with CRA, whereas a high intake of poultry was associated positively with CRA. No clear association with intake of total or specific HCAs and no effect modification by N-acetyltransferase 2 acetylation genotype were observed. We found no statistically significant associations between meat and HCA intake and CRA. These findings do not support a positive association between meat and meat-derived HCA intake and the risk of CRA.

Comparative mutagenic activity of atmospheric particulate matter from limeira, stockholm, and kyoto

Atmospheric particulate matter (PM) organic fractions from urban centers are frequently mutagenic for the Salmonella/microsome assay. This mutagenicity is related to both primary and secondary pollutants, and meteorological conditions have great influence on the secondary pollutant's formation. Our objective was to compare the mutagenicity of atmospheric total suspended particulates (TSP) from three cities with marked different meteorological conditions and TSP concentrations: Limeira (Brazil) with 99.0 μg/m³ , Stockholm (Sweden) with 6.2 μg/m³ , and Kyoto (Japan) with 28.0 μg/m³ . For comparison, we used the same batch of filters, sample extraction method, and Salmonella/microsome testing protocol with 11 strains of Salmonella with and without metabolic activation. Samples were collected during winter and pooled into one single extract representing each city. All samples were mutagenic for all tested strains, except for TA102. Based on the strain's selectivity, nitroarenes, polycyclic aromatic hydrocarbons, and aromatic amines play a predominant role in the mutagenicity of these samples. The mutagenic potencies expressed by mass of extracted organic material (EOM; revertants/μg EOM) were similar (~twofold difference) among the cities, despite differences in meteorological conditions and pollution sources. In contrast, the mutagenic potencies expressed by air volume (rev/m³ ) varied ~20-fold, with Limeira > Kyoto ≈ Stockholm. These results are the first systematic assessment of air mutagenicity from cities on three continents using the same protocols. The results confirm that the mutagenic potency expressed by EOM mass is similar regardless of continent of origin, whereas the mutagenic potency expressed by air volume can vary by orders of magnitude. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.

Carcinogens and DNA damage

Humans are variously and continuously exposed to a wide range of different DNA-damaging agents, some of which are classed as carcinogens. DNA damage can arise from exposure to exogenous agents, but damage from endogenous processes is probably far more prevalent. That said, epidemiological studies of migrant populations from regions of low cancer risk to high cancer risk countries point to a role for environmental and/or lifestyle factors playing a pivotal part in cancer aetiology. One might reasonably surmise from this that carcinogens found in our environment or diet are culpable. Exposure to carcinogens is associated with various forms of DNA damage such as single-stand breaks, double-strand breaks, covalently bound chemical DNA adducts, oxidative-induced lesions and DNA-DNA or DNA-protein cross-links. This review predominantly concentrates on DNA damage induced by the following carcinogens: polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, mycotoxins, ultraviolet light, ionising radiation, aristolochic acid, nitrosamines and particulate matter. Additionally, we allude to some of the cancer types where there is molecular epidemiological evidence that these agents are aetiological risk factors. The complex role that carcinogens play in the pathophysiology of cancer development remains obscure, but DNA damage remains pivotal to this process.

Hypothyroidism induced by phenytoin and gabapentin: A Case Report

RATIONALE

Antiepileptic drugs (AEDs) are one of the causative drugs of drug-induced hypothyroidism. In most cases, AED-induced hypothyroidism is subclinical and indicated only by abnormalities of free thyroxine (T4) and/or thyroid-stimulating hormone (TSH) levels. Severe symptomatic hypothyroidism following AEDs is rarely reported in the literature.

PATIENT CONCERNS

A 75-year-old man experienced neurologic symptoms including memory impairment, ataxic gait, sensory polyneuropathy and myopathy, lethargy, and edema of the face and lower extremities. He had been administered phenytoin and gabapentin for the treatment of symptomatic traumatic epilepsy 8 years before.

DIAGNOSES

The patient had low free T4 (0.21 ng/dL) and high TSH (113.2 μIU/mL), which indicated hypothyroidism. Negative thyroid-related autoantibody tests and the lack of goiter excluded the possibility of Hashimoto disease. Phenytoin and/or gabapentin were strongly suspected as causing his hypothyroidism.

INTERVENTION

The patient was treated with replacement therapy (levothyroxine 25 μg/day).

OUTCOMES

His symptoms markedly and promptly improved alongside continued antiepileptic therapy.

LESSONS

In this case, the patient's hypothyroidism was assumed to result from different mechanisms of the 2 AEDs leading to thyroid hormone reduction. AEDs can not only cause asymptomatic thyroid hormone abnormalities but also clinically observable hypothyroidism. Therefore, clinicians should be aware of the association between anticonvulsants and symptomatic hypothyroidism.

Gabapentin-Induced Bullous Pemphigoid

Bullous pemphigoid is an autoimmune blistering dermatosis with separation of the epidermis from the dermis. This disease process is common among elderly patients and manifests with subepidermal vesicles and tense bullae. Patients with bullous pemphigoid are more likely to have also received a previous diagnosis of a neurologic disorder. Gabapentin is an antiepileptic that is used to manage neuropathic pain. The authors describe, to their knowledge, the first report of gabapentin-induced bullous pemphigoid in an elderly man with no history of rashes or reactions to other medications.

Applications of Biochemical Epidemiology in the Study of Human Carcinogenesis

The measurement of biochemical parameters in epidemiologic studies can contribute to a better understanding of mechanisms of chemical carcinogenesis. Through identification and quantitation of chemicals in tissues or body fluids or through markers of « effective dose » such as DNA adducts, mechanisms of cancer etiology and pathogenesis can be elucidated. Different approaches and the associated methodologic problems are discussed along with examples. As a comprehensive case study, the relationship between aromatic amine exposure and bladder cancer is considered in light of different biochemical aspects which could be the target of epidemiologic studies.

Tissue and Serum TPA in Subjects at Risk for Bladder Cancer

We tested the presence of tumour polypeptide antigen (TPA) in lower urinary tract cells from 59 workers exposed to known bladder carcinogens and from 30 control subjects. We then correlated immunocytological expression and serum TPA levels. Lower urinary tract cells from 31 subjects gave either moderately or strongly positive immunocytological stains. Five also had high serum TPA. The detection of TPA by cytology and in serum differed significantly in workers exposed to cancer agents and the control group.

Gabapentin dose and the 30-day risk of altered mental status in older adults: A retrospective population-based study

Gabapentin is an effective treatment for chronic neuropathic pain but may cause dizziness, drowsiness, and confusion in some older adults. The goal of this study was to assess the association between gabapentin dosing and adverse outcomes by obtaining estimates of the 30-day risk of hospitalization with altered mental status and mortality in older adults (mean age 76 years) in Ontario, Canada initiated on high dose (>600 mg/day; n = 34,159) compared to low dose (≤600 mg/day; n = 76,025) oral gabapentin in routine outpatient care. A population-based, retrospective cohort study assessing new gabapentin use between 2002 to 2014 was conducted. The primary outcome was 30-day hospitalization with an urgent head computed tomography (CT) scan in the absence of evidence of stroke (a proxy for altered mental status). The secondary outcome was 30-day all-cause mortality. The baseline characteristics measured in the two dose groups were similar. Initiation of a high versus low dose of gabapentin was associated with a higher risk of hospitalization with head CT scan (1.27% vs. 1.06%, absolute risk difference 0.21%, adjusted relative risk 1.29 [95% CI 1.14 to 1.46], number needed to treat 477) but not a statistically significant higher risk of mortality (1.25% vs. 1.16%, absolute risk difference of 0.09%, adjusted relative risk of 1.01 [95% CI 0.89 to 1.14]). Overall, the risk of being hospitalized with altered mental status after initiating gabapentin remains low, but may be reduced through the judicious use of gabapentin, use of the lowest dose to control pain, and vigilance for early signs of altered mental status.

Gabapentin for Chronic Neuropathic Pain

CLINICAL QUESTION

Is gabapentin associated with pain relief in people with chronic neuropathic pain?

BOTTOM LINE

Oral gabapentin (1200-3600 mg/d for 4-12 weeks) for patients with moderate or severe neuropathic pain from postherpetic neuralgia (PHN) or painful diabetic neuropathy (PDN) is associated with pain reduction of at least 50% in 14% to 17% more patients than placebo.

Flow cytometric examination of apoptotic effect on brain tissue in postnatal period created by intrauterine oxcarbazepine and gabapentin exposure

OBJECTIVE

For epileptics, pregnancy contains the balance between no seizure period and antiepileptic use having the least teratogenicity risk. The purpose is to analyse with flow cytometry the apoptotic effects on postnatal brain tissue caused by prenatal use of second generation antiepileptics oxcarbazepine (OXC) and gabapentin (GBP) having different effect mechanisms.

METHOD

30 (n = 5 each group) Wistar albino male rats (45-days-old) are used. First 3 groups are exposed to OXC (100 mg/kg/day), GBP (50 mg/kg/day), and saline, respectively on the 1st-5th prenatal days (preimplantation-implantation period) while the second 3 groups are exposed to the same substances on the 6th-15th prenatal days (organogenesis), respectively. After sacrifice, brain tissue samples were made into suspension with mechanic and enzymatic digestion and examined with flow cytometry.

RESULTS

While apoptosis rate appeared high in rats exposed to OXC on the 1st-5th (p < 0.001) and 6th-15th days (p < 0.001), no significant difference occurred for GBP (p = 0.004; p = 0.012) and saline (p = 0.012). Considering time effect in three treatment groups, while difference was not significant for PSS and GBP groups (p = 0.847 and p = 0.934), apoptosis rate was significantly high for OXC on the 6th-15th days compared to the 1st-5th days (p < 0.001).

CONCLUSION

It is observed that the use of OXC causes neurotoxicity during preimplantation, implantation and, especially, organogenesis period (neurogenesis) whereas GBP does not (Fig. 3, Ref. 32).

Abuse potential of gabapentin in dentistry

Gabapentin is an anticonvulsant drug widely prescribed for various ailments, including orofacial pain. It was once thought to have no potential for abuse; however, the last decade has seen a dramatic rise in the nonmedical use of gabapentin, particularly among opioid-dependent patients. Gabapentin is sedating and interacts with other sedating medications such as opioids, which can lead to impairment and accidents and may raise the risk of overdose. Dentists must be aware of the potential for abuse of gabapentin and weigh its benefits against its risks when prescribing the drug.

The Efficacy of Preoperative Gabapentin in Spinal Surgery: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Pain management after spinal surgery has been studied for years. Gabapentin is a third-generation antiepileptic drug that selectively affects the nociceptive process and has been used for pain relief after surgery. However, the relationship between gabapentin and postoperative pain in spinal surgery is still controversial.

OBJECTIVE

To assess the efficacy of the pre-emptive use of gabapentin in spinal surgery.

STUDY DESIGN

A meta-analysis of randomized controlled studies.

SETTING

The MEDLINE, EMBASE, ClinicalTrials.gov, and Web of Science databases were systematically searched.

METHODS

This meta-analysis of randomized controlled trials (RCTs) was performed to compare the use of gabapentin with placebo in spinal surgery regarding to the following: the mean difference (MD) of postoperative opioid requirements, the changes of visual analog scale (VAS) scores in 2 groups, and the incidence rate of adverse effects. An electronic-based search of all related literatures was conducted, and only RCTs for spinal surgery were included. The MD of postoperative opioid requirements and VAS scores and the relative risk (RR) of the incidence rate of adverse effects in the gabapentin group versus the placebo group were extracted throughout the study.

RESULTS

Ten trials, involving 827 patients, met the inclusion criteria and were included in this meta-analysis. The total morphine consumption was significantly lower over the first 24 hours postoperatively in the gabapentin group (P < 0.05). The VAS scores at 2, 4, 6, 12, and 24 hours were less in the gabapentin group (P < 0.05). The incidence rate of vomiting, pruritus, and urinary retention was significantly less in the gabapentin groups (RR = 0.53, 95% CI 0.32-0.86, P < 0.05; RR = 0.38, 95% CI 0.22-0.66, P < 0.05; RR = 0.57, 95% CI 0.34-0.98, P < 0.05, respectively).

LIMITATIONS

All of the studies we screened were published online except for unpublished articles. Only 10 RCTs met our inclusion criteria, so the sample size was still relatively small.

CONCLUSION

This meta-analysis suggests that the administration of gabapentin is effective in reducing postoperative opioid consumption, VAS scores, and some side effects after spinal surgery.

KEY WORDS

Gabapentin, analgesia, spinal surgery, meta-analysis, randomized controlled trials, visual analog scale score, side effect.

Multiple adverse drug reactions and genetic polymorphism testing: A case report with negative result

RATIONALE

Defects in drug metabolic pathways could explain why some patients have a history of multiple adverse drug reactions (ADR); therefore we aimed to analyze genetic polymorphisms in a patient with multiple ADR related to drugs with a common hepatic metabolic pathway through CYP2D6.

PATIENT CONCERNS

We report a patient with psychosis and hypertension related to amitriptyline, tramadol, and duloxetine within a 2-year period.

INTERVENTIONS AND OUTCOMES

A pharmacogenetic test was performed to assess the causative role of the CYP2D6 enzyme, but did not demonstrate a metabolic deficiency.

LESSONS

Although negative results in the reported case; typing for cytochrome P450 isoenzyme polymorphisms could be a useful diagnostic tool in some patients with a history of multiple ADR.

Formation of heterocyclic amines in Chinese marinated meat: effects of animal species and ingredients (rock candy, soy sauce and rice wine)

BACKGROUND

Heterocyclic aromatic amines (HAAs) are one type of neo-formed contaminants in protein-rich foods during heat processing. Recently, accumulative studies have focused on the formation of HAs in Western foods. However, there is little knowledge about the occurrence of HAAs in traditional Chinese foods. The objective of this study was to determinate the contents of main HAs in traditional marinated meat products by UPLC-MS/MS, and to investigate the effects of animal species and the ingredients (soy sauce, rock candy, and rice wine) on the formation of HAAs in marinated meats.

RESULTS

Five HAs - 2-amino-3-methylimidazo[4,5-f]-quinolone (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4-dimethylimidazo[4,5-f]quinoxaline (MeIQ), 9H-pyrido[3,4-b]indole (Norharman) and l-methyl-9H-pyrido[3,4-b]indole (Harman) - were detected in 12 marinated meats, but 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was only found in three chicken marinates. The animal species and ingredients (soy sauce, rock candy and rice wine) have significant influence on the formation of HAAs in meat marinates. Beef had the highest content of total HAAs compared with pork, mutton and chicken. Meanwhile, soy sauce contributed to the formation of HAAs more greatly than rock candy, soy sauce, and rice wine.

CONCLUSION

Choice of raw materials and optimisation of ingredients recipe should be become a critical point to control the HAAs formation in marinated meats. © 2017 Society of Chemical Industry.

A meta-analysis of the preoperative use of gabapentinoids for the treatment of acute postoperative pain following spinal surgery

BACKGROUND

Gabapentinoid drugs, which include gabapentin and pregabalin, play an established role in the management of neuropathic pain. However, whether preoperative administration of gabapentinoids has a beneficial role in controlling acute pain after spinal surgery is unknown. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to determine the efficacy and safety of the preoperative use of gabapentinoids (gabapentin and pregabalin) for the treatment of acute postoperative pain following spinal surgery.

METHODS

In March 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, Cochrane Library, and Google databases. RCTs comparing gabapentinoids (gabapentin and pregabalin) with placebo in patients undergoing spine surgery were retrieved. The primary endpoint was the visual analogue scale (VAS) score with rest or mobilization at 6, 12, 24, and 48 hours and cumulative morphine consumption at 24 and 48 hours. The secondary outcomes were complications of nausea, vomiting, sedation, dizziness, headache, urine retention, pruritus, and visual disturbances. After tests for publication bias and heterogeneity among studies were performed, data were aggregated for random-effects models when necessary.

RESULTS

Sixteen clinical studies (gabapentin group n = 8 and pregabalin group n = 8) were ultimately included in the meta-analysis. Gabapentinoids were associated with reduced pain scores at 6, 12, 24, and 48 hours. Similarly, gabapentinoids were associated with a reduction in cumulative morphine consumption at 24 and 48 hours. Furthermore, gabapentinoids can significantly reduce the occurrence of nausea, vomiting, and pruritus. There were no significant differences in the occurrence of sedation, dizziness, headache, visual disturbances, somnolence, or urine retention.

CONCLUSIONS

Preoperative use of gabapentinoids was able to reduce postoperative pain, total morphine consumption, and morphine-related complications following spine surgery. Further studies should determine the optimal dose and whether pregabalin is superior to gabapentin in controlling acute pain after spine surgery.

Antiepileptic drugs for chronic non-cancer pain in children and adolescents

BACKGROUND

Pain is a common feature of childhood and adolescence around the world, and for many young people, that pain is chronic. The World Health Organization (WHO) guidelines for pharmacological treatments for children's persisting pain acknowledge that pain in children is a major public health concern of high significance in most parts of the world. While in the past, pain was largely dismissed and was frequently left untreated, views on children's pain have changed over time, and relief of pain is now seen as importantWe designed a suite of seven reviews on chronic non-cancer pain and cancer pain (looking at antidepressants, antiepileptic drugs, non-steroidal anti-inflammatory drugs, opioids, and paracetamol) in order to review the evidence for children's pain utilising pharmacological interventions in children and adolescents.As the leading cause of morbidity in the world today, chronic disease (and its associated pain) is a major health concern. Chronic pain (that is pain lasting three months or longer) can occur in the paediatric population in a variety of pathophysiological classifications (nociceptive, neuropathic, or idiopathic) relating to genetic conditions, nerve damage pain, chronic musculoskeletal pain, and chronic abdominal pain, and for other unknown reasons.Antiepileptic (anticonvulsant) drugs, which were originally developed to treat convulsions in people with epilepsy, have in recent years been used to provide pain relief in adults for many chronic painful conditions and are now recommended for the treatment of chronic pain in the WHO list of essential medicines. Known side effects of antiepileptic drugs range from sweating, headache, elevated temperature, nausea, and abdominal pain to more serious effects including mental or motor function impairment.

OBJECTIVES

To assess the analgesic efficacy and adverse events of antiepileptic drugs used to treat chronic non-cancer pain in children and adolescents aged between birth and 17 years, in any setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online, MEDLINE via Ovid, and Embase via Ovid from inception to 6 September 2016. We also searched the reference lists of retrieved studies and reviews as well as online clinical trial registries.

SELECTION CRITERIA

Randomised controlled trials, with or without blinding, by any route, treating chronic non-cancer pain in children and adolescents, comparing any antiepileptic drug with placebo or an active comparator.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility. We planned to use dichotomous data to calculate risk ratio and number needed to treat for one additional event, using standard methods if data were available. We assessed the evidence using GRADE and created two 'Summary of findings' tables.

MAIN RESULTS

We included two studies with a total of 141 participants (aged 7 to 18 years) with chronic neuropathic pain, complex regional pain syndrome type 1 (CRPS-I), or fibromyalgia. One study investigated pregabalin versus placebo in participants with fibromyalgia (107 participants), and the other study investigated gabapentin versus amitriptyline in participants with CRPS-I or neuropathic pain (34 participants). We were unable to perform any quantitative analysis.Risk of bias for the two included studies varied, due to issues with randomisation (low to unclear risk), blinding of outcome assessors (low to unclear risk), reporting bias (low to unclear risk), the size of the study populations (high risk), and industry funding in the 'other' domain (low to unclear risk). We judged the remaining domains of sequence generation, blinding of participants and personnel, and attrition as low risk of bias. Primary outcomesOne study (gabapentin 900 mg/day versus amitriptyline 10 mg/day, 34 participants, for 6 weeks) did not report our primary outcomes (very low-quality evidence).The second study (pregabalin 75 to 450 mg/day versus placebo 75 to 450 mg/day, 107 participants, for 15 weeks) reported no significant change in pain scores for pain relief of 30% or greater between pregabalin 18/54 (33.3%), and placebo 16/51 (31.4%), P = 0.83 (very low-quality evidence). This study also reported Patient Global Impression of Change, with the percentage of participants feeling "much or very much improved" with pregabalin 53.1%, and placebo 29.5% (very low-quality evidence).We downgraded the evidence by three levels to very low for one of two reasons: due to the fact that there was no evidence to support or refute the use of the intervention, or that there were too few data and the number of events was too small to be meaningful. Secondary outcomesIn one small study, adverse events were uncommon: gabapentin 2 participants (2 adverse events); amitriptyline 1 participant (1 adverse event) (6-week trial). The second study reported a higher number of adverse events: pregabalin 38 participants (167 adverse events); placebo 34 participants (132 adverse events) (15-week trial) (very low-quality evidence).Withdrawals due to adverse events were infrequent in both studies: pregabalin (4 participants), placebo (4 participants), gabapentin (2 participants), and amitriptyline (1 participant) (very low-quality evidence).Serious adverse events were reported in both studies. One study reported only one serious adverse event (cholelithiasis and major depression resulting in hospitalisation in the pregabalin group) and the other study reported no serious adverse events (very low-quality evidence).There were few or no data for our remaining secondary outcomes (very low-quality evidence).We downgraded the evidence by three levels to very low due to too few data and the fact that the number of events was too small to be meaningful.

AUTHORS' CONCLUSIONS

This review identified only two small studies, with insufficient data for analysis.As we could undertake no meta-analysis, we were unable to comment about efficacy or harm from the use of antiepileptic drugs to treat chronic non-cancer pain in children and adolescents. Similarly, we could not comment on our remaining secondary outcomes: Carer Global Impression of Change; requirement for rescue analgesia; sleep duration and quality; acceptability of treatment; physical functioning; and quality of life.We know from adult randomised controlled trials that some antiepileptics, such as gabapentin and pregabalin, can be effective in certain chronic pain conditions.We found no evidence to support or refute the use of antiepileptic drugs to treat chronic non-cancer pain in children and adolescents.

Antidepressants for chronic non-cancer pain in children and adolescents

BACKGROUND

Pain is a common feature of childhood and adolescence around the world, and for many young people, that pain is chronic. The World Health Organization guidelines for pharmacological treatments for children's persisting pain acknowledge that pain in children is a major public health concern of high significance in most parts of the world. While in the past pain was largely dismissed and was frequently left untreated, views on children's pain have changed over time and relief of pain is now seen as important.We designed a suite of seven reviews on chronic non-cancer pain and cancer pain (looking at antidepressants, antiepileptic drugs, non-steroidal anti-inflammatory drugs, opioids, and paracetamol) in order to review the evidence for children's pain utilising pharmacological interventions.As the leading cause of morbidity in the world today, chronic disease (and its associated pain) is a major health concern. Chronic pain (that is pain lasting three months or longer) can arise in the paediatric population in a variety of pathophysiological classifications (nociceptive, neuropathic, or idiopathic) from genetic conditions, nerve damage pain, chronic musculoskeletal pain, and chronic abdominal pain, as well as for other unknown reasons.Antidepressants have been used in adults for pain relief and pain management since the 1970s. The clinical impression from extended use over many years is that antidepressants are useful for some neuropathic pain symptoms, and that effects on pain relief are divorced and different from effects on depression; for example, the effects of tricyclic antidepressants on pain may occur at different, and often lower, doses than those on depression. Amitriptyline is one of the most commonly used drugs for treating neuropathic pain in the UK.

OBJECTIVES

To assess the analgesic efficacy and adverse events of antidepressants used to treat chronic non-cancer pain in children and adolescents aged between birth and 17 years, in any setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online, MEDLINE via Ovid, and Embase via Ovid from inception to 6 September 2016. We also searched the reference lists of retrieved studies and reviews, and searched online clinical trial registries.

SELECTION CRITERIA

Randomised controlled trials, with or without blinding, of any dose and any route, treating chronic non-cancer pain in children and adolescents, comparing any antidepressant with placebo or an active comparator.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility. We planned to use dichotomous data to calculate risk ratio and number needed to treat for one additional event, using standard methods. We assessed the evidence using GRADE and created three 'Summary of findings' tables.

MAIN RESULTS

We included four studies with a total of 272 participants (6 to 18 years of age) who had either chronic neuropathic pain, complex regional pain syndrome type 1, irritable bowel syndrome, functional abdominal pain, or functional dyspepsia. All of the studies were small. One study investigated amitriptyline versus gabapentin (34 participants), two studies investigated amitriptyline versus placebo (123 participants), and one study investigated citalopram versus placebo (115 participants). Due to a lack of available data we were unable to complete any quantitative analysis.Risk of bias for the four included studies varied, due to issues with randomisation and allocation concealment (low to unclear risk); blinding of participants, personnel, and outcome assessors (low to unclear risk); reporting of results (low to unclear risk); and size of the study populations (high risk). We judged the remaining domains, attrition and other potential sources of bias, as low risk of bias. Primary outcomesNo studies reported our primary outcomes of participant-reported pain relief of 30% or greater or 50% or greater (very low-quality evidence).No studies reported on Patient Global Impression of Change (very low-quality evidence).We rated the overall quality of the evidence (GRADE rating) as very low. We downgraded the quality of the evidence by three levels to very low because there was no evidence to support or refute. Secondary outcomesAll studies measured adverse events, with very few reported (11 out of 272 participants). All but one adverse event occurred in the active treatment groups (amitriptyline, citalopram, and gabapentin). Adverse events in all studies, across active treatment and comparator groups, were considered to be a mild reaction, such as nausea, dizziness, drowsiness, tiredness, and abdominal discomfort (very low-quality evidence).There were also very few withdrawals due to adverse events, again all but one from the active treatment groups (very low-quality evidence).No serious adverse events were reported across any of the studies (very low-quality evidence).There were few or no data for our remaining secondary outcomes (very low-quality evidence).We rated the overall quality of the evidence (GRADE rating) for these secondary outcomes as very low. We downgraded the quality of the evidence by three levels to very low due to too few data and the fact that the number of events was too small to be meaningful.

AUTHORS' CONCLUSIONS

We identified only a small number of studies with small numbers of participants and insufficient data for analysis.As we could undertake no meta-analysis, we are unable to comment about efficacy or harm from the use of antidepressants to treat chronic non-cancer pain in children and adolescents. Similarly, we cannot comment on our remaining secondary outcomes: Carer Global Impression of Change; requirement for rescue analgesia; sleep duration and quality; acceptability of treatment; physical functioning; and quality of life.There is evidence from adult randomised controlled trials that some antidepressants, such as amitriptyline, can provide some pain relief in certain chronic non-cancer pain conditions.There is no evidence from randomised controlled trials to support or refute the use of antidepressants to treat chronic non-cancer pain in children or adolescents.

Antiepileptic drugs for chronic non-cancer pain in children and adolescents

BACKGROUND

Pain is a common feature of childhood and adolescence around the world, and for many young people, that pain is chronic. The World Health Organization (WHO) guidelines for pharmacological treatments for children's persisting pain acknowledge that pain in children is a major public health concern of high significance in most parts of the world. While in the past, pain was largely dismissed and was frequently left untreated, views on children's pain have changed over time, and relief of pain is now seen as importantWe designed a suite of seven reviews on chronic non-cancer pain and cancer pain (looking at antidepressants, antiepileptic drugs, non-steroidal anti-inflammatory drugs, opioids, and paracetamol) in order to review the evidence for children's pain utilising pharmacological interventions in children and adolescents.As the leading cause of morbidity in the world today, chronic disease (and its associated pain) is a major health concern. Chronic pain (that is pain lasting three months or longer) can occur in the paediatric population in a variety of pathophysiological classifications (nociceptive, neuropathic, or idiopathic) relating to genetic conditions, nerve damage pain, chronic musculoskeletal pain, and chronic abdominal pain, and for other unknown reasons.Antiepileptic (anticonvulsant) drugs, which were originally developed to treat convulsions in people with epilepsy, have in recent years been used to provide pain relief in adults for many chronic painful conditions and are now recommended for the treatment of chronic pain in the WHO list of essential medicines. Known side effects of antiepileptic drugs range from sweating, headache, elevated temperature, nausea, and abdominal pain to more serious effects including mental or motor function impairment.

OBJECTIVES

To assess the analgesic efficacy and adverse events of antiepileptic drugs used to treat chronic non-cancer pain in children and adolescents aged between birth and 17 years, in any setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online, MEDLINE via Ovid, and Embase via Ovid from inception to 6 September 2016. We also searched the reference lists of retrieved studies and reviews as well as online clinical trial registries.

SELECTION CRITERIA

Randomised controlled trials, with or without blinding, by any route, treating chronic non-cancer pain in children and adolescents, comparing any antiepileptic drug with placebo or an active comparator.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility. We planned to use dichotomous data to calculate risk ratio and number needed to treat for one additional event, using standard methods if data were available. We assessed the evidence using GRADE and created two 'Summary of findings' tables.

MAIN RESULTS

We included two studies with a total of 141 participants (aged 7 to 18 years) with chronic neuropathic pain, complex regional pain syndrome type 1 (CRPS-I), or fibromyalgia. One study investigated pregabalin versus placebo in participants with fibromyalgia (107 participants), and the other study investigated gabapentin versus amitriptyline in participants with CRPS-I or neuropathic pain (34 participants). We were unable to perform any quantitative analysis.Risk of bias for the two included studies varied, due to issues with randomisation (low to unclear risk), blinding of outcome assessors (low to unclear risk), reporting bias (low to unclear risk), the size of the study populations (high risk), and industry funding in the 'other' domain (low to unclear risk). We judged the remaining domains of sequence generation, blinding of participants and personnel, and attrition as low risk of bias. Primary outcomesOne study (gabapentin 900 mg/day versus amitriptyline 10 mg/day, 34 participants, for 6 weeks) did not report our primary outcomes (very low-quality evidence).The second study (pregabalin 75 to 450 mg/day versus placebo 75 to 450 mg/day, 107 participants, for 15 weeks) reported no significant change in pain scores for pain relief of 30% or greater between pregabalin 18/54 (33.3%), and placebo 16/51 (31.4%), P = 0.83 (very low-quality evidence). This study also reported Patient Global Impression of Change, with the percentage of participants feeling "much or very much improved" with pregabalin 53.1%, and placebo 29.5% (very low-quality evidence).We downgraded the evidence by three levels to very low for one of two reasons: due to the fact that there was no evidence to support or refute the use of the intervention, or that there were too few data and the number of events was too small to be meaningful. Secondary outcomesIn one small study, adverse events were uncommon: gabapentin 2 participants (2 adverse events); amitriptyline 1 participant (1 adverse event) (6-week trial). The second study reported a higher number of adverse events: pregabalin 38 participants (167 adverse events); placebo 34 participants (132 adverse events) (15-week trial) (very low-quality evidence).Withdrawals due to adverse events were infrequent in both studies: pregabalin (4 participants), placebo (4 participants), gabapentin (2 participants), and amitriptyline (1 participant) (very low-quality evidence).Serious adverse events were reported in both studies. One study reported only one serious adverse event (cholelithiasis and major depression resulting in hospitalisation in the pregabalin group) and the other study reported no serious adverse events (very low-quality evidence).There were few or no data for our remaining secondary outcomes (very low-quality evidence).We downgraded the evidence by three levels to very low due to too few data and the fact that the number of events was too small to be meaningful.

AUTHORS' CONCLUSIONS

This review identified only two small studies, with insufficient data for analysis.As we could undertake no meta-analysis, we were unable to comment about efficacy or harm from the use of antiepileptic drugs to treat chronic non-cancer pain in children and adolescents. Similarly, we could not comment on our remaining secondary outcomes: Carer Global Impression of Change; requirement for rescue analgesia; sleep duration and quality; acceptability of treatment; physical functioning; and quality of life.We know from adult randomised controlled trials that some antiepileptics, such as gabapentin and pregabalin, can be effective in certain chronic pain conditions.We found no evidence to support or refute the use of antiepileptic drugs to treat chronic non-cancer pain in children and adolescents.

Elevated levels of AST, ALT, and CPK · no family history of liver disease · Dx?

A 26-year-old healthy male veteran with bipolar disorder and post-traumatic stress disorder was referred for a gastroenterology consultation after a routine laboratory evaluation revealed elevated levels of aspartate aminotransferase, 1040 IU/L (normal range, 10-40 IU/L), and alanine aminotransferase, 334 IU/L (normal range, 7-56 IU/L). He had been taking divalproex and ziprasidone for the previous 2 years, during which time liver test results had been normal.

Gabapentin for chronic neuropathic pain in adults

BACKGROUND

Gabapentin is commonly used to treat neuropathic pain (pain due to nerve damage). This review updates a review published in 2014, and previous reviews published in 2011, 2005 and 2000.

OBJECTIVES

To assess the analgesic efficacy and adverse effects of gabapentin in chronic neuropathic pain in adults.

SEARCH METHODS

For this update we searched CENTRAL), MEDLINE, and Embase for randomised controlled trials from January 2014 to January 2017. We also searched the reference lists of retrieved studies and reviews, and online clinical trials registries.

SELECTION CRITERIA

We included randomised, double-blind trials of two weeks' duration or longer, comparing gabapentin (any route of administration) with placebo or another active treatment for neuropathic pain, with participant-reported pain assessment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality and potential bias. Primary outcomes were participants with substantial pain relief (at least 50% pain relief over baseline or very much improved on Patient Global Impression of Change scale (PGIC)), or moderate pain relief (at least 30% pain relief over baseline or much or very much improved on PGIC). We performed a pooled analysis for any substantial or moderate benefit. Where pooled analysis was possible, we used dichotomous data to calculate risk ratio (RR) and number needed to treat for an additional beneficial outcome (NNT) or harmful outcome (NNH). We assessed the quality of the evidence using GRADE and created 'Summary of findings' tables.

MAIN RESULTS

We included four new studies (530 participants), and excluded three previously included studies (126 participants). In all, 37 studies provided information on 5914 participants. Most studies used oral gabapentin or gabapentin encarbil at doses of 1200 mg or more daily in different neuropathic pain conditions, predominantly postherpetic neuralgia and painful diabetic neuropathy. Study duration was typically four to 12 weeks. Not all studies reported important outcomes of interest. High risk of bias occurred mainly due to small size (especially in cross-over studies), and handling of data after study withdrawal.In postherpetic neuralgia, more participants (32%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (17%) (RR 1.8 (95% CI 1.5 to 2.1); NNT 6.7 (5.4 to 8.7); 8 studies, 2260 participants, moderate-quality evidence). More participants (46%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (25%) (RR 1.8 (95% CI 1.6 to 2.0); NNT 4.8 (4.1 to 6.0); 8 studies, 2260 participants, moderate-quality evidence).In painful diabetic neuropathy, more participants (38%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (21%) (RR 1.9 (95% CI 1.5 to 2.3); NNT 5.9 (4.6 to 8.3); 6 studies, 1277 participants, moderate-quality evidence). More participants (52%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (37%) (RR 1.4 (95% CI 1.3 to 1.6); NNT 6.6 (4.9 to 9.9); 7 studies, 1439 participants, moderate-quality evidence).For all conditions combined, adverse event withdrawals were more common with gabapentin (11%) than with placebo (8.2%) (RR 1.4 (95% CI 1.1 to 1.7); NNH 30 (20 to 65); 22 studies, 4346 participants, high-quality evidence). Serious adverse events were no more common with gabapentin (3.2%) than with placebo (2.8%) (RR 1.2 (95% CI 0.8 to 1.7); 19 studies, 3948 participants, moderate-quality evidence); there were eight deaths (very low-quality evidence). Participants experiencing at least one adverse event were more common with gabapentin (63%) than with placebo (49%) (RR 1.3 (95% CI 1.2 to 1.4); NNH 7.5 (6.1 to 9.6); 18 studies, 4279 participants, moderate-quality evidence). Individual adverse events occurred significantly more often with gabapentin. Participants taking gabapentin experienced dizziness (19%), somnolence (14%), peripheral oedema (7%), and gait disturbance (14%).

AUTHORS' CONCLUSIONS

Gabapentin at doses of 1800 mg to 3600 mg daily (1200 mg to 3600 mg gabapentin encarbil) can provide good levels of pain relief to some people with postherpetic neuralgia and peripheral diabetic neuropathy. Evidence for other types of neuropathic pain is very limited. The outcome of at least 50% pain intensity reduction is regarded as a useful outcome of treatment by patients, and the achievement of this degree of pain relief is associated with important beneficial effects on sleep interference, fatigue, and depression, as well as quality of life, function, and work. Around 3 or 4 out of 10 participants achieved this degree of pain relief with gabapentin, compared with 1 or 2 out of 10 for placebo. Over half of those treated with gabapentin will not have worthwhile pain relief but may experience adverse events. Conclusions have not changed since the previous update of this review.

Radiologic Findings in Gabapentin-Induced Myositis

Throughout recent years, Gabapentin has become increasingly used for the treatment of neuropathic pain. We report on a case of a 31 year old female who presented to the emergency department with unilateral leg pain, weakness, and swelling after increasingly titrating her Gabapentin dosage over three weeks. Magnetic resonance imaging confirmed the presence of myositis confined to the left thigh and the patient's symptoms and laboratory abnormalities resolved following Gabapentin cessation. While Gabapentin-induced myositis and rhabdomyolysis is a rare entity, it should be a diagnostic consideration for radiologists, particularly in the absence of infection or trauma.

The comparative preemptive analgesic efficacy of addition of vitamin B complex to gabapentin versus gabapentin alone in women undergoing cesarean section under spinal anesthesia: A prospective randomized double-blind study

BACKGROUND

Development of new multimodal analgesic regimens have led to substantial improvement in postoperative pain relief. We designed this study to compare the effect of combined vitamin B complex-gabapentin versus gabapentin alone on postoperative pain in women undergoing cesarean section under spinal anesthesia.

METHODS

One hundred twenty-eight women who underwent cesarean section under spinal anesthesia were randomized to receive orally 300 mg gabapentin (group G) or 300 mg of gabapentin plus 2 vitamin B complex (group GB) tablets 30 minutes before surgery. Postoperative pain intensity and total analgesic consumption during 12 hours after surgery, vomiting, and drowsiness during recovery were assessed.

RESULTS

The pain intensity in the gabapentin plus vitamin B complex group was lower than gabapentin group during 12 hours after surgery (95% CI: 1.4-2.2; P < .001). Meanwhile, the total analgesic consumption in this group was less than gabapentin alone (95% CI: 1.07-1.24; P = 0.034). The incidence of vomiting in patients who receive combined gabapentin-vitamin B complex group was similar to gabapentin alone (P = .206). The difference of the distribution of the relative frequency of sedation according to Ramsay sedation scores in patients between 2 groups were insignificant (P = .82). All newborns in our study were free of any adverse effects.

CONCLUSION

Addition of vitamin B complex to gabapentin reduced intensity of postoperative pain and also the total amount of analgesic consumption within the first 12 hours postoperative following cesarean section.

An Atypical Withdrawal Syndrome in Neonates Prenatally Exposed to Gabapentin and Opioids

We report a retrospective case series of 19 infants exposed to both opioids and gabapentin prenatally. We describe a unique behavioral phenotype in 15 of these infants and report a treatment strategy.

Gabapentin-induced aquagenic wrinkling of the palms

Aquagenic keratoderma (AK) or aquagenic wrinklingis a rare palmoplantar skin disease. It is sporadic orhereditary condition. It appears in childhood or youngadulthood and it is seen as multiple asymptomaticsmall shiny papules on the peripheral margin ofpalms and/or soles after submersion in water. Thepathogenesis and etiology of ASA remains unclear.Drugs sometimes trigger AK. Herein, we present thecase of a 29-year-old man who had begun treatmentwith gabapentin three weeks before the onset of hiscutaneous symptoms.

Gabapentin for fibromyalgia pain in adults

BACKGROUND

This review replaces part of an earlier review that evaluated gabapentin for both neuropathic pain and fibromyalgia, now split into separate reviews for the two conditions. This review will consider pain in fibromyalgia only.Fibromyalgia is associated with widespread pain lasting longer than three months, and is frequently associated with symptoms such as poor sleep, fatigue, depression, and reduced quality of life. Fibromyalgia is more common in women.Gabapentin is an antiepileptic drug widely licensed for treatment of neuropathic pain. It is not licensed for the treatment of fibromyalgia, but is commonly used because fibromyalgia can respond to the same medicines as neuropathic pain.

OBJECTIVES

To assess the analgesic efficacy of gabapentin for fibromyalgia pain in adults and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online, MEDLINE via Ovid and Embase via Ovid from inception to 24 May 2016. We also searched the reference lists of retrieved studies and reviews, and searched online clinical trial registries.

SELECTION CRITERIA

Randomised, double-blind trials of eight weeks' duration or longer for treating fibromyalgia pain in adults, comparing gabapentin with placebo or an active comparator.

DATA COLLECTION AND ANALYSIS

Two independent review authors extracted data and assessed trial quality and risk of bias. We planned to use dichotomous data to calculate risk ratio and number needed to treat for one additional event, using standard methods. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created a 'Summary of findings' table.

MAIN RESULTS

Two studies tested gabapentin to treat fibromyalgia pain. One was identified in previous versions of the review and is included here. We identified another study as a conference abstract, with insufficient detail to determine eligibility for inclusion; it is awaiting assessment. The one included study of 150 participants was a 12-week, multi-centre, randomised, double-blind, placebo-controlled, parallel-group study using last-observation-carried-forward imputation for withdrawals. The maximum dose was 2400 mg daily. The overall risk of bias was low, except for attrition bias.At the end of the trial, the outcome of 50% reduction in pain over baseline was not reported. The outcome of 30% or greater reduction in pain over baseline was achieved by 38/75 participants (49%) with gabapentin compared with 23/75 (31%) with placebo (very low quality). A patient global impression of change any category of "better" was achieved by 68/75 (91%) with gabapentin and 35/75 (47%) with placebo (very low quality).Nineteen participants discontinued the study because of adverse events: 12 in the gabapentin group (16%) and 7 in the placebo group (9%) (very low quality). The number of serious adverse events were not reported, and no deaths were reported (very low quality).

AUTHORS' CONCLUSIONS

We have only very low quality evidence and are very uncertain about estimates of benefit and harm because of a small amount of data from a single trial. There is insufficient evidence to support or refute the suggestion that gabapentin reduces pain in fibromyalgia.

Gabapentin-Induced Severe Myopathy

Objective:

To report and discuss a case of rhabdomyolysis in an elderly patient with neuropathic pain who was treated with gabapentin.

Case Summary:

An 85-year-old diabetic woman was hospitalized for severe pain in her lower limbs and difficulty in walking, compromising her daily activities. On admission, the woman's laboratory parameters, including creatine kinase (CK) and myoglobin, were in the normal range. Neurologic evaluation suggested a diagnosis of diabetic neuropathic pain, and therapy with gabapentin 150 mg 3 times daily was started. On the same day, the patient developed psychomotor agitation and gastric pain, which were treated with haloperidol 10 mg and lansoprazole 30 mg, respectively. In the following hours, the severity of muscular pain increased and the patient developed myopathy with acute renal failure (CK 459 U/L, myoglobin 11 437 ng/mL, creatinine 4.59 mg/dL), which worsened progressively during the next 2 days (CK 3095 U/L, myoglobin 17 000 mg/dL, creatinine 4.77 mg/dL) despite discontinuation of haloperidol and lansoprazole. No signs of trauma or edema, suggesting possible compartmental or crush syndrome, were detected. Gabapentin was then withdrawn and the patient's condition rapidly improved. Complete recovery followed in about 10 days.

Discussion:

Severe myopathy is an unexpected adverse reaction to gabapentin therapy. In this patient, a possible contribution of haloperidol or lansoprazole to the adverse event cannot be excluded. However, worsening of the clinical picture despite discontinuation of these drugs, together with rapid improvement observed after withdrawal of gabapentin, strongly suggest a causative role of gabapentin. According to the Naranjo probability scale, gabapentin was the probable cause of myopathy in this patient. The mechanism by which gabapentin may induce myopathy is unknown. The early onset of the syndrome after initiation of treatment with gabapentin in therapeutic doses is compatible with the picture of an idiosyncratic adverse response.

Conclusions:

Pathogenetic and clinical investigations are required to explore what mechanisms account for gabapentin-related muscular alterations at the time of onset, including electromyographic recordings as well as muscle and nerve histopathologic examinations. Until more information is available, clinicians should consider the possibility of discontinuing gabapentin treatment in patients showing muscular pain and signs of myopathy.

Potential harmful effects of dietary supplements in sports medicine

PURPOSE OF REVIEW

The purpose of this article is to collect the most recent data regarding the safety of well-known or emerging dietary supplements used by athletes.

RECENT FINDINGS

From January 2014 to April 2016, about 30 articles have been published in the field. New data show that 90% of sports supplements contain trace of estrogenic endocrine disruptors, with 25% of them having a higher estrogenic activity than acceptable. About 50% of the supplements are contaminated by melamine, a source of nonprotein nitrogen. Additional data accumulate toward the safety of nitrate ingestion. In the last 2 years, the safety of emerging supplements such as higenamine, potentially interesting to lose weight, creatine nitrate and guanidinoacetic acid has been evaluated but still needs further investigation.

SUMMARY

The consumption of over-the-counter supplements is very popular in athletes. Although most supplements may be considered as safe when taking at the recommended doses, athletes should be aware of the potential risks linked to the consumption of supplements. In addition to the risks linked to overdosage and cross-effects when combining different supplements at the same time, inadvertent or deliberate contamination with stimulants, estrogenic compounds, diuretics or anabolic agents may occur.

Structural basis for inhibition of a voltage-gated Ca2+ channel by Ca2+ antagonist drugs

Ca²⁺ antagonist drugs are widely used in therapy of cardiovascular disorders. Three chemical classes of drugs bind to three separate, but allosterically interacting, receptor sites on Ca_V1.2 channels, the most prominent voltage-gated Ca²⁺ (Ca_V) channel type in myocytes in cardiac and vascular smooth muscle. The 1,4-dihydropyridines are used primarily for treatment of hypertension and angina pectoris and are thought to act as allosteric modulators of voltage-dependent Ca²⁺ channel activation, whereas phenylalkylamines and benzothiazepines are used primarily for treatment of cardiac arrhythmias and are thought to physically block the pore. The structural basis for the different binding, action, and therapeutic uses of these drugs remains unknown. Here we present crystallographic and functional analyses of drug binding to the bacterial homotetrameric model Ca_V channel Ca_VAb, which is inhibited by dihydropyridines and phenylalkylamines with nanomolar affinity in a state-dependent manner. The binding site for amlodipine and other dihydropyridines is located on the external, lipid-facing surface of the pore module, positioned at the interface of two subunits. Dihydropyridine binding allosterically induces an asymmetric conformation of the selectivity filter, in which partially dehydrated Ca²⁺ interacts directly with one subunit and blocks the pore. In contrast, the phenylalkylamine Br-verapamil binds in the central cavity of the pore on the intracellular side of the selectivity filter, physically blocking the ion-conducting pathway. Structure-based mutations of key amino-acid residues confirm drug binding at both sites. Our results define the structural basis for binding of dihydropyridines and phenylalkylamines at their distinct receptor sites on Ca_V channels and offer key insights into their fundamental mechanisms of action and differential therapeutic uses in cardiovascular diseases.

Comparative persistence of antiepileptic drugs in patients with epilepsy: A STROBE-compliant retrospective cohort study

We compared persistence of antiepileptic drugs (AEDs) including carbamazepine, oxcarbazepine, gabapentin, lamotrigine, topiramate, valproic acid, and phenytoin in an Asian population with epilepsy.A retrospective cohort study was conducted by analyzing Taiwan's National Health Insurance Research Database (NHIRD). Adult epilepsy patients newly prescribed with AEDs between 2005 and 2009 were included. The primary outcome was persistence, defined as the treatment duration from the date of AED initiation to the date of AED discontinuation, switching, hospitalization due to seizure or disenrollment from databases, whichever came first. Cox proportional hazard models were used to estimate the risk of non-persistence with AEDs.Among the 13,061 new users of AED monotherapy (mean age: 58 years; 60% men), the persistence ranged from 218.8 (gabapentin) to 275.9 (oxcarbazepine) days in the first treatment year. The risks of non-persistence in patients receiving oxcarbazepine (adjusted hazard ratio [HR], 0.78; 95% CI, 0.74-0.83), valproic acid (0.88; 0.85-0.92), lamotrigine (0.72; 0.65-0.81), and topiramate (0.90; 0.82-0.98) were significantly lower than in the carbamazepine group. Compared with carbamazepine users, the non-persistence risk was higher in phenytoin users (1.10; 1.06-1.13), while gabapentin users (1.03; 0.98-1.09) had similar risk. For risk of hospitalization due to seizure and in comparison with carbamazepine users, oxcarbazepine (0.66; 0.58-0.74) and lamotrigine (0.46; 0.35-0.62) users had lower risk, while phenytoin (1.35; 1.26-1.44) users had higher risk. The results remained consistent throughout series of sensitivity and stratification analyses.The persistence varied among AEDs and was better for oxcarbazepine, valproic acid, lamotrigine, and topiramate, but worse for phenytoin when compared with carbamazepine.

The Effect of Gabapentin on Acute Postoperative Pain in Patients Undergoing Total Knee Arthroplasty: A Meta-Analysis

The purpose of this systematic review and meta-analysis of randomized controlled trials (RCTs) and non-RCTs was to evaluate the efficacy and safety of gabapentin versus placebo for pain control after total knee arthroplasty (TKA).In December 2015, a systematic computer-based search was conducted in the Medline, Embase, PubMed, Cochrane Controlled Trials Register (CENTRAL), Web of Science, Google, and Chinese Wanfang databases. This systematic review and meta-analysis were performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement criteria. The primary endpoint was the visual analogue scale (VAS) score after TKA with rest or mobilization at 24 and 48 hours, representing the efficacy of pain control after TKA. Cumulative morphine consumption via patient controlled anesthesia (PCA) was also assessed to determine the morphine-spare effect. Complications such as dizziness, pruritus, vomiting, nausea, and sedation were also compiled to assess the safety of gabapentin. Stata 12.0 software was used for the meta-analysis. After testing for publication bias and heterogeneity across studies, the data were aggregated for random-effects modeling whenever necessary.Six studies involving 769 patients met the inclusion criteria. Our meta-analysis revealed that gabapentin resulted in superior pain relief compared to the control group in terms of VAS score with rest at 24 hours (mean difference [MD] = -3.47; 95% confidence interval [CI] -6.16 to -0.77; P = 0.012) and at 48 hours postoperatively (MD = -2.25; 95% CI -4.21 to -0.30; P = 0.024). There was no statistically significant difference between the groups with respect to the VAS score at 24 hours postoperatively (MD = 1.05; 95% CI -3.31 to 5.42; P = 0.636) or at 48 hours (MD = 1.71; 95% CI -0.74 to 4.15; P = 0.171). These results indicated that the perioperative administration of gabapentin decreases the cumulative morphine consumption via PCA at 24 hours (MD = -8.28; 95% CI -12.57 to -3.99; P = 0.000) and 48 hours (MD = -4.50; 95% CI -10.98 to -3.61; P = 0.221). Furthermore, gabapentin decreased the rate of postoperative dizziness (relative risk [RR], 0.68; 95% CI 0.47-0.99, P = 0.044) and the occurrence of pruritus (RR, 0.50; 95% CI 0.37-0.67, P = 0.000).Based on the current meta-analysis, gabapentin exerts an analgesic and opioid-sparing effect in acute postoperative pain management without increasing the rate of dizziness and pruritus.

Clinical Trial Assessing the Efficacy of Gabapentin Plus B Complex (B1/B12) versus Pregabalin for Treating Painful Diabetic Neuropathy

INTRODUCTION

Painful diabetic neuropathy (PDN) is a prevalent and impairing disorder. The objective of this study was to show the efficacy and safety of gabapentin (GBP) plus complex B vitamins: thiamine (B1) and cyanocobalamine (B12) compared to pregabalin in patients with moderate to severe intensity PDN.

METHOD

Multicenter, randomized, blind study. Two hundred and seventy patients were evaluated, 147 with GBP/B1/B12 and 123 with PGB, with a 7/10 pain intensity on the Visual Analog Scale (VAS). Five visits (12 weeks) were scheduled. The GBP/B1 (100 mg)/B12 (20 mg) group started with 300 mg at visit 1 to 3600 mg at visit 5. The PGB group started with 75 mg/d at visit 1 to 600 mg/d at visit 5. Different safety and efficacy scales were applied, as well as adverse event assessment.

RESULTS

Both drugs showed reduction of pain intensity, without significant statistical difference (P = 0.900). In the GBP/B1/B12 group, an improvement of at least 30% on VAS correlated to a 900 mg/d dose, compared with PGB 300 mg/d. Likewise, occurrence of vertigo was lower in the GBP/B1-B12 group, with a significant statistical difference, P = 0.014.

CONCLUSIONS

Our study shows that GPB/B1-B12 combination is as effective as PGB. Nonetheless, pain intensity reduction is achieved with 50% of the minimum required gabapentin dose alone (800 to 1600 mg/d) in classic NDD trials. Less vertigo and dizziness occurrence was also observed in the GBP/B1/B12 group. This trial is registered with ClinicalTrials.gov NCT01364298.

Impact of Periconceptional Use of Nitrosatable Drugs on the Risk of Neural Tube Defects

Nitrosatable drugs (NSDs) can, in the presence of nitrosating agents and highly acidic conditions, form N-nitroso compounds that have been found to be teratogenic in animal models. Using data from the Slone Epidemiology Center Birth Defects Study collected from 1998 to 2012, we compared maternal periconceptional NSD use between 334 neural tube defect cases and 7,619 nonmalformed controls. We categorized NSDs according to their functional group (secondary amine, tertiary amine, and amide). With logistic regression models, we estimated adjusted odds ratios and 95% confidence intervals. Neural tube defect risk was associated with maternal periconceptional use of secondary (adjusted odds ratio (aOR) = 1.7, 95% confidence interval (CI): 1.1, 2.4) and tertiary (aOR = 1.7, 95% CI: 1.2, 2.5) amines; an association was observed for amides, but the 95% confidence interval included the null (aOR = 1.4, 95% CI: 0.7, 2.5). Within the secondary amine group, elevated adjusted odds ratios were observed for 3 drugs but were null for the remaining medications. Increases in risk were observed for both strata of folic acid intake (<400 µg/day, ≥400 µg/day), with a slightly higher risk in the ≥400-µg/day stratum. Our findings support previously reported positive associations between neural tube defects and periconceptional exposure to NSDs containing a secondary or tertiary amine or amide.