Role of genetic polymorphisms in clopidogrel response variability: a systematic review

INTRODUCTION

Clopidogrel is a P2Y12 inhibitor that has become a mainstay treatment following percutaneous intervention with drug-eluting stent placement to decrease restenosis and its potential complications, including sudden cardiac death and ischaemic strokes in patients with significant vascular disease.

AREAS COVERED

As a prodrug, the metabolism and efficacy of clopidogrel are contingent on the presence of wild-type CYP450 (CYP2C19) alleles. Genetic polymorphisms and variants are well known to impair its ability to prevent major adverse cardiovascular events in these patients, with inadequate response rates as high as 30% in previous publications. Patterns of allelic frequencies are expected to exhibit similarities between individuals of the same ancestry, ethnic group or geographic region. Accordingly, we seek to further elucidate worldwide prevalence rates for genetic polymorphisms in the CYP2C19-dependent metabolism of clopidogrel and review the potential of personalised CYP2C19 genotyping in clinical practice to mitigate this high treatment resistance and its associated burden on patients.

EXPERTS' COMMENTARY

Our findings support the consideration of genotyping before initiation of therapy to guide adequate dosage or substitutions of other P2Y12 inhibitors to promote personalised, precision medicine and to prevent adverse events when these therapies may inevitably fail in patients with variants of the CYP450 (CYP2C19) system.

Effects of rifampin coadministration on the pharmacokinetics of digoxin: a real-world data approach

Digoxin, a cardiac glycoside, is commonly prescribed to treat heart failure and atrial fibrillation. Because digoxin acts as a substrate of P-glycoprotein (P-gp), its blood concentration may be reduced by P-gp inducers such as rifampin. To assess the real-world implications of this drug-drug interaction, a retrospective analysis was carried out on the Clinical Data Warehouse at Seoul National University Hospital between 2012 and 2017. Eleven patients who received both digoxin and rifampin with satisfying the inclusion/exclusion criteria were identified. The Ctrough values of digoxin monotherapy were compared to those of the combination therapy with rifampin. Results demonstrated that the systemic exposure of orally administered digoxin decreased by 40% with the concurrent use of rifampin. Clinicians should be aware of potential drug interactions between digoxin and rifampin, as adjustments to digoxin dosage might be necessary for patients receiving rifampin or other P-gp inducer drugs.

In vitro combination of antifungal drugs with tacrolimus (FK506) holds promise against clinical Candida species including Candida auris

In vitro interactions between tacrolimus, a calcineurin inhibitor, and fluconazole, itraconazole, caspofungin, or anidulafungin were evaluated against Candida auris, C. albicans, C. parapsilosis, and C. glabrata (each five strains). Tacrolimus-itraconazole, tacrolimus-caspofungin, and tacrolimus-fluconazole combinations resulted in synergistic interactions against 95%, 90%, and 60% of Candida isolates, respectively. Contradictory, tacrolimus-anidulafungin resulted in only a 35% synergistic effect. A combination of tacrolimus and itraconazole was most potent with synergy against 100% of C. auris, C. parapsilosis, and C. glabrata isolates. Of note, no antagonistic interaction was found.

Patterns of psychotropic drug use in veterans with epilepsy: Do drug interactions matter?

RATIONALE

Patients with epilepsy are likely to suffer from psychiatric comorbidities, including depression and anxiety. They often require treatment with multiple psychotropic drugs (PDs). While it is clear that CYP-inducing ASMs (EIASMs) can increase the oral clearance of multiple medications (thus lowering systemic exposure), it is less clear that all PK interactions are clinically meaningful (e.g. lower efficacy). As a first step in addressing this issue, this study sought to quantify the potential impact of ASM choice, whether EIASM or non-inducer (NIASM), on surrogate markers of suggestive of clinical use, including resultant antidepressant (AD) or antipsychotic (AP) dose, frequency of combination use of AD & AP, and number of multiple drug switches of PDs. Our hypothesis is that because of PK interactions, EIAED treatment would be associated with higher psychotropic drug doses, more frequent Rx adjustments and poly psychotropic comedication, all in order to optimize therapeutic response.

METHODS

Using VA pharmacy and national encounter databases, veterans with epilepsy were identified based on having a seizure diagnosis and being prescribed concomitantly an ASM and a psychotropic drug for at least 365 days between 10/1/2010 and 9/30/2014. Patients for whom psychotropic drugs were prescribed any time between beginning and end prescriptions dates of ASMs were considered. Among those, patients receiving both an EIASM + NEIASM concomitantly were categorized with the EIASM group. Patients were evaluated for AD only, AP only and both (AD & AP). To compute average drug doses per day, averages for each patient were computed and averaged again. Multiple drug switches were defined to be for patients who had been prescribed more than three psychotropic drugs during the observation period. Pearson's Chi-Square test was used to compare relative proportions of AD, AP and AD + AP in both groups.

RESULTS

In all, 16,188 patients were identified (57.0% on EIASM, 43.0% on NIASM) with a mean age of 58.7 years (91.2% male). A larger proportion of patients on EIASM received mono treatment with any psychotropic drug, as compared to NIASM (42.0% vs 36.1%). Among all, 59.6% received AD only, 6.5% received AP only, and 33.8% received both concurrently. Of EIASM, 62.5% were on AD, 5.9% on AP, and 31.7% on both AP & AD. For NIASM, 55.9% received AD, 7.4% AP, and 36.7% on AD & AP.Chi-square showed that the distribution of PD was statistically different between EIASM and NIASM groups. Z tests showed that each difference (AD, AP and both) in proportions was statistically significant (p values (4 tests, one Chi-square, 3 Z tests <0.001) between EIASM vs NIASM. Interestingly, mean doses of AD or AP did not appear to differ between ASM groups.

CONCLUSIONS

Concurrent psychotropic drug use is quite common in the VA population with epilepsy, and a large number of patients still receive enzyme-inducing ASMs that may complicate other medical therapies. Interestingly, in seeming contradiction to our hypothesis, mean daily doses of either AD or AP did not appear to differ between inducers vs non-inducers. Similarly, use of polytherapy, and/or multiple trials of various psychotropic drugs did not appear increased in the CYP-induced group. In fact, combination therapy of AD + AP was higher in NIASM than EIASM. These data suggest that perhaps these types of PK interactions may not in fact result in meaningful clinical differences. Since the present analyses did not include clinical psychiatric measures, future analyses examining direct clinical outcomes are clearly warranted.

Evaluation of pharmacokinetic drug-drug interaction between tegoprazan and clarithromycin in healthy subjects

Tegoprazan is a novel potassium-competitive acid blocker that treats gastric acid-related diseases. Clarithromycin was widely used as one of various regimens for eradicating Helicobacter pylori. This study compared the pharmacokinetic and safety profile of tegoprazan and clarithromycin between combination therapy and monotherapy to evaluate the potential drug-drug interaction. An open-label, randomized, 6-sequence, 3-period crossover study was conducted in 24 healthy subjects. According to the assigned sequence, the subject was administered the assigned treatment during 5 days in each period. PK parameters of tegoprazan and clarithromycin administered in combination were compared with those of the respective monotherapies. The co-administration of tegoprazan with clarithromycin increased maximum steady-state plasma concentration (C_ss,max) and area under the plasma concentration-time curve in dosing interval at steady-state (AUC_ss,tau) of tegoprazan (1.6-fold in C_ss,max and 2.5-fold in AUC_ss,tau) and M1 (2.0-fold in C_ss,max, 2.5-fold in AUC_ss,tau) than tegoprazan alone. The C_ss,max and AUC_ss,tau of 14-hydroxyclarithromycin increased 1.8- and 2.0-fold in co-administration, respectively. The AUC_ss.tau of clarithromycin was slightly increased in co-administration, but C_ss,max was not changed. Combination of tegoprazan and clarithromycin and those of the respective monotherapies were tolerated in 24 healthy subjects. There may exist drug interaction that lead to reciprocal increase in plasma drug concentrations when tegoprazan and clarithromycin were administrated in combination and no safety concerns were raised. It is suggested that an in-depth analysis of the concentration-response relationship is necessary to determine whether these concentration changes warrant clinical action.

Trial Registration

ClinicalTrials.gov Identifier: NCT02052336.

Effect of cocoa (Theobroma cacao L.) on platelet function testing profiles in patients with coronary artery disease: ECLAIR pilot study

INTRODUCTION

This prospective pharmacodynamic nutraceutical study assessed the effect of a 1-week trial of 30 g/day of 65% cocoa (dark chocolate) (Theobroma cacao L.) consumption intervention on platelet reactivity.

METHODS

Patients with stable coronary artery disease (CAD) (n=20) who were on maintenance dual antiplatelet therapy of aspirin (ASA) 81 mg/day and clopidogrel 75 mg/day were recruited. Platelet function was evaluated with the VerifyNow P2Y₁₂ reaction unit (PRU) and aspirin reaction unit (ARU) assays (Werfen, Bedford, Massachusetts, USA) and assessed prior to initiation of and after a 1-week trial of 30 g/day of 65% cocoa consumption intervention. Results were compared with a paired t-test.

RESULTS

Cocoa augmented the inhibitory effect of clopidogrel, demonstrated by a reduction of 11.9% (95% CI 5.7% to 18.0%, p value 0.001), significantly decreasing the PRU by 26.85 (95% CI 12.22 to 41.48, p value 0.001). The inhibitory effect of ASA was not impacted by cocoa, reflected by a non-significant reduction in ARU of 17.65 (95% CI 21.00 to 56.3, p value 0.351). No patients experienced any serious adverse events.

CONCLUSIONS

Cocoa augmented the inhibitory effect of clopidogrel but not ASA. This nutraceutical study could be potentially informative and applicable for patients with stable CAD. Further long-term studies are required to confirm these exploratory findings.

TRIAL REGISTRATION NUMBER

NCT04554901.

Optimization of Performance by Combining Most Sensitive and Specific Models in Data Science Results in Majority Voting Ensemble

Ensemble modeling is an increasingly popular data science technique that combines the knowledge of multiple base learners to enhance predictive performance. In this paper, the idea was to increase predictive performance by holding out three algorithms when testing multiple classifiers: (a) the best overall performing algorithm (based on the harmonic mean of sensitivity and specificity (HMSS) of that algorithm); (b) the most sensitive model; and (c) the most specific model. This approach boils down to majority voting between the predictions of these three base learners. In this exemplary study, a case of identifying a prolonged QT interval after administering a drug-drug interaction with increased risk of QT prolongation (QT-DDI) is presented. Performance measures included accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Overall performance was measured by calculating the HMSS. Results show an increase in all performance measure characteristics compared to the original best performing algorithm, except for specificity where performance remained stable. The presented approach is fairly simple and shows potential to increase predictive performance, even without adjusting the default cut-offs to differentiate between high and low risk cases. Future research should look at a way of combining all tested algorithms, instead of using only three. Similarly, this approach should be tested on a multiclass prediction problem.

Pharmacological interactions between intrathecal pregabalin plus tianeptine or clopidogrel in a rat model of neuropathic pain

Background

There is still unmet need in treating neuropathic pain and increasing awareness regarding the use of drug combinations to increase the effectiveness of treatment and reduce adverse effects in patients with neuropathic pain.

Methods

This study was performed to determine the individual and combined effects of pregabalin, tianeptine, and clopidogrel in a rat model of neuropathic pain. The model was created by ligation of the L5-L6 spinal nerve in male Sprague-Dawley rats; mechanical allodynia was confirmed using von Frey filaments. Drugs were administered to the intrathecal space and mechanical allodynia was assessed; drug interactions were estimated by isobolographic or fixed-dose analyses.

Results

Intrathecal pregabalin and tianeptine increased the mechanical withdrawal threshold in a dose-dependent manner, but intrathecal clopidogrel had little effect on the mechanical withdrawal threshold. An additive effect was noted between pregabalin and tianeptine, but not between pregabalin and clopidogrel.

Conclusions

These findings suggest that intrathecal coadministration of pregabalin and tianeptine effectively attenuated mechanical allodynia in the rat model of neuropathic pain. Thus, pregabalin plus tianeptine may be a valid option to enhance the efficacy of neuropathic pain treatment.

Complications of combination intranasal corticosteroids and anti-retroviral therapy

BACKGROUND

Intranasal corticosteroids are widely used for management of many upper airway diseases because of their ability to effectively deliver local relief of inflammation.

CASE REPORT

This paper presents the case of a 51-year-old man with human immunodeficiency virus treated with ritonavir who was started on fluticasone intranasal spray for presumed chronic rhinosinusitis. Months after starting this therapy, he developed symptoms of Cushing's syndrome and avascular necrosis of the shoulder due to the pharmacological interactions between fluticasone and ritonavir.

CONCLUSION

Although intranasal corticosteroids are deemed a low-risk route of drug administration, clinicians need to be vigilant in appropriately prescribing corticosteroids in the setting of drug potentiators, particularly in these high-risk patients. Alternative corticosteroids such as beclomethasone dipropionate should be considered in such cases.

Prescribing intranasal steroids in HIV-positive patients: systematic review of the literature

BACKGROUND

There are significant drug-drug interactions between human immunodeficiency virus antiretroviral therapy and intranasal steroids, leading to high serum concentrations of iatrogenic steroids and subsequently Cushing's syndrome.

METHOD

All articles in the literature on cases of intranasal steroid and antiretroviral therapy interactions were reviewed. Full-length manuscripts were analysed and the relevant data were extracted.

RESULTS

A literature search and further cross-referencing yielded a total of seven reports on drug-drug interactions of intranasal corticosteroids and human immunodeficiency virus protease inhibitors, published between 1999 and 2019.

CONCLUSION

The use of potent steroids metabolised via CYP3A4, such as fluticasone and budesonide, are not recommended for patients taking ritonavir or cobicistat. Mometasone should be used cautiously with ritonavir because of pharmacokinetic similarities to fluticasone. There was a delayed onset of symptoms in many cases, most likely due to the relatively lower systemic bioavailability of intranasal fluticasone.

Association Between Benzodiazepine or Z-Drug Prescriptions and Drug-Related Poisonings Among Patients Receiving Buprenorphine Maintenance: A Case-Crossover Analysis

OBJECTIVE

Persons with opioid use disorder who take benzodiazepines are at high risk for overdose. The objective of this study was to evaluate the association of benzodiazepine and Z-drug use with drug-related poisonings among patients receiving buprenorphine maintenance treatment.

METHODS

A case-crossover study design was used to analyze prescription claims among persons ages 12-64 with opioid use disorder who had buprenorphine prescriptions and had claims data in the IBM MarketScan databases (2006-2016), encompassing 14,213,075 person-days of observation time for 23,036 individuals who experienced drug-related poisoning. The exposures were buprenorphine prescriptions and benzodiazepine or Z-drug prescriptions, standardized as daily diazepam-equivalent milligram doses and separated by pharmacologic properties (short-acting or long-acting benzodiazepines, Z-drugs). The outcome of interest was nonfatal drug-related poisoning. Conditional logistic regression was used to evaluate variation in benzodiazepine or Z-drug and buprenorphine use between poisoning and nonpoisoning days.

RESULTS

Buprenorphine treatment days were associated with a nearly 40% reduction in the risk of poisoning events (odds ratio=0.63, 95% CI=0.60, 0.66) compared with nontreatment days, whereas benzodiazepine or Z-drug treatment days were associated with an 88% increase in the risk of such events (95% CI=1.78, 1.98). In stratified analyses by dose, we observed a 78% (95% CI=1.67, 1.88) and 122% (95% CI=2.03, 2.43) increase in poisonings associated with low-dose and high-dose benzodiazepine or Z-drug treatment days, respectively. High-dose, but not low-dose, benzodiazepine or Z-drug treatment was associated with increased poisonings in combination with buprenorphine cotreatment (odds ratio=1.64, 95% CI=1.39, 1.93), but this was lower than the odds risk associated with benzodiazepine or Z-drug treatment in the absence of buprenorphine (low-dose: odds ratio=1.69, 95% CI=1.60, 1.79; high-dose: odds ratio=2.23, 95% CI=2.04, 2.45).

CONCLUSIONS

Increased risk of nonfatal drug-related poisoning is associated with benzodiazepine or Z-drug treatment in patients with opioid use disorder, but this risk is partially mitigated by buprenorphine treatment. Dose reduction of benzodiazepines or Z-drugs while maintaining buprenorphine treatment may provide the advantage of lowering drug-related poisoning risk.

Interactions between cardiology and oncology drugs in precision cardio-oncology

Recent advances in treatment have transformed the management of cancer. Despite these advances, cardiovascular disease remains a leading cause of death in cancer survivors. Cardio-oncology has recently evolved as a subspecialty to prevent, diagnose, and manage cardiovascular side effects of antineoplastic therapy. An emphasis on optimal management of comorbidities and close attention to drug interactions are important in cardio-oncologic care. With interdisciplinary collaboration among oncologists, cardiologists, and pharmacists, there is potential to prevent and reduce drug-related toxicities of treatments. The cytochrome P450 (CYP450) family of enzymes and the P-glycoprotein (P-g) transporter play a crucial role in drug metabolism and drug resistance. Here we discuss the role of CYP450 and P-g in drug interactions in the field of cardio-oncology, provide an overview of the cardiotoxicity of a spectrum of cancer agents, highlight the role of precision medicine, and encourage a multidisciplinary treatment approach for patients with cancer.

The Impact of Perioperative Use of a Statin-Magnesium Combination on Opioid Consumption in Patients Who Underwent Cardiac Surgery: A Retrospective Study with Propensity-Score Matching

Both statins and magnesium are associated with NMDA receptors and anti-inflammatory effect. Peripheral NMDA receptors are known to be involved in inflammation-induced pain. This study aimed to investigate the impact of perioperative use of a statin–magnesium combination on opioid consumption in patients who underwent cardiac surgery. This was a retrospective study of 542 patients who underwent cardiac surgery. The patients were divided into two groups according to statin use: the statin–magnesium group (n=375) and the magnesium-only group (n=167). Patients in the magnesium-only group received only perioperative magnesium, but no statins, to prevent atrial fibrillation following cardiac surgery. After propensity-score matching, 228 patients (n=114 in each group) were analyzed to investigate opioid consumption, visual analogue scale (VAS) pain scores over a 72-h period, and pain outcomes according to the duration of statin treatment (<1 or ≥1 yr). The consumed opioid volume was significantly smaller in statin–magnesium group than the magnesium-only group, both before (p=0.010) and after matching (p=0.017). The statin–magnesium combination did not significantly reduce the VAS pain scores compared with magnesium alone. Although the statin–magnesium combination did not significantly reduce the pain intensity compared with magnesium alone, the combination therapy was effective in reducing opioid consumption after surgery.

Prediction of Drug-Drug Interactions by Using Profile Fingerprint Vectors and Protein Similarities

Objectives

Drug-drug interaction (DDI) is a vital problem that threatens people's health. However, the prediction of DDIs through in-vivo experiments is not only extremely costly but also difficult as many serious side effects are hard to detect in in-vivo and in-vitro settings. The aim of this study was to assess the effectiveness of similarity-based in-silico computational DDI prediction approaches and to provide a cost effective and scalable solution to predict potential DDIs.

Methods

In this study, widely known similarity-based computational DDI prediction methods were utilized to discover novel potential DDIs. More specifically, known interactions, drug targets, adverse effects, and protein similarities of drug pairs were used to construct drug fingerprints for the prediction of DDIs.

Results

Using the drug interaction profile, our approach achieved an area under the curve (AUC) of 0.975 in the prediction of a potential DDI. The drug adverse effect profile and protein profile similarity-based methods resulted in AUC values of 0.685 and 0.895, respectively, in the prediction of DDIs.

Conclusions

In this study, we developed a computational approach to the prediction of potential drug interactions. The performance of the similarity-based computational methods was comparatively evaluated using a comprehensive real-world DDI dataset. The evaluations showed that the drug interaction profile information is a better predictor of DDIs compared to drug adverse effects and protein similarities among DDI pairs.

Statin-induced delayed rhabdomyolysis

An elderly woman with a history of hypertension, hypothyroidism, mesenteric vein thrombosis, depression and hyperlipidaemia on statins for >9 years presented with new-onset leg weakness, falls, dark-coloured urine, transaminitis and rhabdomyolysis (creatinine phosphokinase 12 896 U/L; aldolase 45.9 (normal <7.7 U/L). Workup for autoimmune myositis was negative. The patient had clinical and laboratory improvement with discontinuation of statins with the return of clinical strength and creatinine phosphokinase back to baseline levels (51 U/L) within 2 weeks.

Performance Evaluation of Clinical Decision Support Systems (CDSS): Developing a Business Intelligence (BI) Dashboard

This document describes the development of a Business Intelligence (BI) dashboard for tracking the drug-drug interaction (DDI) alerts implemented as Clinical Decision Support Systems (CDSS) in Electronic Health Records (EHR). CDSS are known for their potential to reduce medical error. The use of requirements in the development of BI dashboards is crucial to obtain successful software. In this work, the requirements were analysed using a score methodology, considering the relevance of the indicators and visualization methods. CDSS effectiveness and acceptance have been questioned, so it is fundamental to monitor their behaviour and performance. The dashboard was designed in order to satisfy the needed indicators. Using BI as a tool for monitoring the CDSS performance made it possible to operationalize the EHR content repository, maximizing the understanding in relation to the override and, by inference, to optimize the CDSS system by opening new lines of work.

Evaluating a Clinical Decision Support System for Drug-Drug Interactions

Janusmed is a clinical decision support system, developed by the Stockholm County Council that supports physicians in identifying drug-drug interactions. To determine how Janusmed is used in and affects the clinical practice, an evaluation study is currently being carried out that analyzes multiple data sources through descriptive statistics. The study focuses on how Janusmed affects the behavior of the physicians, in particular, to what extent physicians reconsider their prescription decisions based on warnings from Janusmed.

Drug-drug interactions and pharmacists' interventions among psychiatric patients in outpatient clinics of a teaching hospital in Saudi Arabia

Background

Lack of recognition of labeled drug-drug interactions (DDIs) is a type of medication error of particular relevance to the treatment of psychiatric patients. Pharmacists are in a position to detect and address potential DDIs.

Objective

This study aimed to explore pharmacists' role in the identification and management of DDIs among psychiatric patients in psychiatric outpatient clinics of a university-affiliated tertiary care hospital in Riyadh, Saudi Arabia.

Method

This study was a retrospective, cross-sectional medical chart review of patients visiting outpatient psychiatric clinics. It utilized medical records of patients who were taking any psychotropic medications and were prescribed at least one additional drug. The hospital Computerized Physician Order Entry system was used to identify DDIs and determine the pharmacists' interventions. The Beers criteria were applied to detect inappropriate prescribing among older patients.

Results

On average, the pharmacists intervened in 12 out of 213 (5.6%) cases of major or moderate DDIs. Older age, higher number of prescription medications, the severity of DDIs, and the utilization of lithium and anticoagulants were positively associated with the pharmacist undertaking an action.

Conclusion

Future studies should explore the prevalence rate of harmful DDIs among psychiatric patients on a large scale and examine the effectiveness of different pharmacy policies in the detection and management of DDIs.

Tobacco smoking and its drug interactions with comedications involving CYP and UGT enzymes and nicotine

Tobacco smoking is a global public health threat causing several illnesses including cardiovascular disease (Myocardial infarction), cerebrovascular disease (Stroke), peripheral vascular disease (Claudication), chronic obstructive pulmonary disease, asthma, reduced female infertility, sexual dysfunction in men, different types of cancer and many other diseases. It has been estimated in 2015 that approximately 1.3 billion people smoke, around the globe. Use of medications among smokers is more common, nowadays. This review is aimed to identify the medications affected by smoking, involving Cytochrome P450 (CYP) and uridine diphosphate-glucuronosyltransferases (UGTs) enzymes and Nicotine. Polycyclic aromatic hydrocarbons (PAHs) of tobacco smoke have been associated with the induction of CYP enzymes such as CYP1A1, CYP1A2 and possibly CYP2E1 and UGT enzymes. The drugs metabolized by CYP1A1, CYP1A2, CYP2E1 and UGT enzymes might be affected by tobacco smoking and the smokers taking medications metabolized by those enzymes, may need higher doses due to decreased plasma concentrations through enhanced induction by PAHs of tobacco smoke. The prescribers and the pharmacists are required to be aware of medications affected by tobacco smoking to prevent the toxicity-associated complications during smoking cessation.

Isoniazid-induced pure red cell aplasia

The pure red cell aplasia (PRCA) is an uncommon side effect of isoniazid. We describe a 28-year-old man who developed a severe anaemia caused by PRCA. The patient received antituberculous therapy including isoniazid for his pulmonary tuberculosis. On discontinuation of isoniazid, the anaemia recovered promptly. PRCA should be considered in case of unexplained anaemia during isoniazid treatment.

Pharmacological activity of Curarea toxicofera in combination with classical antimalarial treatments

ETHNOPHARMACOLOGICAL RELEVANCE

In the Leticia-Amazonas area, Uitoto indigenous people use a preparation of Curarea toxicofera (Wedd) Barneby & Krukoff (Menispermaceae) alone or combined with prescribed medications to prevent and treat malaria.

AIM OF STUDY

To determine the in vitro and in vivo antiplasmodial activity of traditional preparations of Curarea toxicofera alone and in combination with classical antimalarials.

MATERIAL AND METHODS

The traditional preparation was evaluated in vitro against P. falciparum FCR3 CQ resistant strain, alone and combined. The preparation was further administered orally alone or combined with chloroquine and artesunate in mice infected with Plasmodium berghei ANKA strain on the four-day antimalarial test model.

RESULTS

The herbal remedy used alone was able to significantly decrease the parasitemia both in vitro (IC₅₀ 7.3 µg/ml) and in vivo (ED₅₀ 328 mg/Kg) but it was less active than chloroquine (IC₅₀ 0.29 µg/ml in vitro and ED₅₀ 2.3 mg/Kg/day in vivo), and than artesunate (IC₅₀ 0.002 µg/ml and ED₅₀ 3.7 mg/Kg/day). Interestingly it presented synergism with chloroquine in vitro (Combination Index: 0.39) and in vivo; and was additive with artesunate in vitro (Combination Index: 0.94) and in vivo.

CONCLUSION

The traditional preparation showed potential as an antimalarial and, when used in combination, does not negatively affect the efficacy of the drugs evaluated. Pre-clinical studies should be conducted with a standardized preparation to confirm its efficacy and safety alone and in combination with chloroquine and artesunate.

Interaction between ABCG2 421C>A polymorphism and valproate in their effects on steady-state disposition of lamotrigine in adults with epilepsy

AIMS

To investigate the impact of glucuronidation enzyme (UGT1A4*3 142T>G, UGT1A4*2 70C>A, UGT2B7 -161C>T) and transporter (MDR1/ABCB1 1236C>T, ABCG2 421C>A) polymorphisms on steady-state disposition of lamotrigine and on the lamotrigine-valproate interaction.

METHODS

Adults with epilepsy on lamotrigine monotherapy (n = 131) or lamotrigine + valproate treatment (n = 74) were genotyped and steady-state lamotrigine and valproate morning troughs were determined as a part of routine therapeutic drug monitoring.

RESULTS

No effect of UGT and MDR1/ABCB1 polymorphisms was observed. In the entire cohort, ABCG2 421A allele had no effect however an interaction between the variant allele and valproate was observed: (i) in lamotrigine-only patients, variant allele (vs. wild type homozygosity) was independently (adjustments: age, sex, body mass index, lamotrigine dose, other polymorphisms) associated with mildly lower lamotrigine troughs [geometric means ratio (GMR) = 0.76, 95% confidence interval (CI) 0.59-0.98], whereas in lamotrigine + valproate patients it was associated with higher troughs (GMR = 1.72, 95%CI 1.14-2.62); (ii) valproate cotreatment was overall associated with markedly higher troughs vs. lamotrigine monotherapy (GMR = 3.49, 95%CI 2.73-4.44), but more so in variant allele carriers (GMR = 5.24, 95%CI 3.38-8.15) than in wild type homozygotes (GMR = 2.32, 95%CI 1.89-2.83); (iii) variant allele effects in two treatment subsets and valproate effects in two genotype subsets differed by 2.36-fold (95%CI 1.39-3.67); (iv) increase in lamotrigine troughs associated with increasing valproate troughs was greater in variant allele carriers than in wild type homozygotes, i.e. variant allele effect increased with increasing valproate troughs.

CONCLUSION

This study is first to indicate a potentially relevant interaction between ABCG2 421C>A polymorphism and valproate in their effects on lamotrigine disposition.

Evaluation of a Clinical Pharmacist Intervention on Clinical and Drug-Related Problems Among Coronary Heart Disease Inpatients: A pre-experimental prospective study at a general hospital in Indonesia

Objectives

This study aimed to evaluate the role of a clinical pharmacist intervention in decreasing subsequent clinical and drug-related problems (DRPs) among coronary heart disease (CHD) inpatients with at least one previous DRP.

Methods

This pre-experimental study with a pre-post design was carried out from January to April 2017 among inpatients with at least one previous DRP at a general hospital in Tangerang District, Banten, Indonesia. Clinical and DRPs were documented prospectively by a clinical pharmacist, with DRPs classified using Version 6.2 of the DRP classification scheme of the Pharmaceutical Care Network Europe Foundation. The intervention consisted of a discussion of identified DRPs with physicians, patients, pharmaceutical logistics clerks, nurses and nutritionists. Following this, any subsequent clinical and DRPs were re-identified and further interventions were conducted as necessary.

Results

A total of 75 inpatients were included in the study. Pre-intervention, there were 443 DRPs and 202 clinical problems. The most frequent DRPs were adverse drug reactions (52.6%), followed by drug effects (41.8%). Most DRPs were of moderate severity and would have resulted in moderate consequences had the pharmacist not intervened. The interventions resulted in a significant reduction in the number of DRPs, type of DRPs and number of clinical problems (P <0.05 each). Patients with complications were 26.047 times more likely to have no reduction or an increased number of clinical problems compared to patients without complications (P <0.05).

Conclusion

Clinical pharmacist interventions were found to reduce subsequent DRPs and clinical problems among CHD patients with at least one previous DRP.

Secondary Adrenal Insufficiency Due to the Co-Administration of Ritonavir and Inhaled Fluticasone Propionate: Case report

Ritonavir is a powerful inhibitor of the cytochrome P450 3A4 (CYP3A4) isoenzyme. It is used as a pharmaceutical enhancer in the management of HIV-positive patients. However, when co-administered with other drugs that are metabolised via the CYP3A4 pathway, ritonavir can potentially cause serious drug-drug interactions. Inhaled fluticasone propionate, which is used to treat asthma and chronic obstructive airway disease, is particularly prone to such interactions due to its physiological attributes. We report a HIV-positive 48-year-old male patient who presented to Al Nahdha Hospital, Muscat, Oman, in 2012 with weight loss, generalised weakness and fatigue and diagnosed with secondary adrenal insufficiency as a result of concomitant ritonavir and inhaled fluticasone.

Abciximab-induced acute profound thrombocytopenia postpercutaneous coronary intervention

Abciximab (c7E3 Fab) is one of the three potent intravenous glycoprotein IIb/IIIa receptor inhibitors (along with eptifibatide and tirofiban) that have shown significant positive outcomes when used in patients with intracoronary thrombus. However, major side effects have been reported with its use including hypotension, major bleeding and thrombocytopenia. This case is a 53-year-old man presenting with acute chest pain diagnosed with non-ST-elevation myocardial infarction, who underwent percutaneous coronary intervention with abciximab and heparin infusion and developed acute profound thrombocytopenia (platelet count <20,000/L) within 9 hours of infusion. This case demonstrates the importance of routinely monitoring the platelet count prior to and 2-4 hours following abciximab infusion and differentiating other causes of acute profound thrombocytopenia, particularly pseudothrombocytopenia and heparin-induced thrombocytopenia.

General Anaesthesia Protocols for Patients Undergoing Electroconvulsive Therapy: Retrospective analysis of 504 sessions over a five-year period at a tertiary care hospital in Oman

OBJECTIVES

This study aimed to review general anaesthesia protocols for patients undergoing electroconvulsive therapy (ECT) at a tertiary care hospital in Oman, particularly with regards to clinical profile, potential drug interactions and patient outcomes.

METHODS

This retrospective study took place at the Sultan Qaboos University Hospital (SQUH), Muscat, Oman. The electronic medical records of patients undergoing ECT at SQUH between January 2010 and December 2014 were reviewed for demographic characteristics and therapy details.

RESULTS

A total of 504 modified ECT sessions were performed on 57 patients during the study period. All of the patients underwent a uniform general anaesthetic regimen consisting of propofol and succinylcholine; however, they received different doses between sessions, as determined by the treating anaesthesiologist. Variations in drug doses between sessions in the same patient could not be attributed to any particular factor. Self-limiting tachycardia and hypertension were periprocedural complications noted among all patients. One patient developed aspiration pneumonitis (1.8%).

CONCLUSION

All patients undergoing ECT received a general anaesthetic regimen including propofol and succinylcholine. However, the interplay of anaesthetic drugs with ECT efficacy could not be established due to a lack of comprehensive data, particularly with respect to seizure duration. In addition, the impact of concurrent antipsychotic therapy on anaesthetic dose and subsequent complications could not be determined.

User-Centered Design Improves the Usability of Drug-Drug Interaction Alerts: A Validation Study in the Real Scenario

Decision support systems can alert physicians to the existence of drug interactions. The Hospital Italiano de Buenos Aires, Argentina, has an in-house electronic health record with computerized physician order entry and clinical decision support. It includes a drug-drug interaction alert system, initially developed under traditional engineering techniques. As we detected a high alert override rate, we rebuilt the knowledge database and redesigned the alert interface with User-Centered Design techniques. A laboratory crossover study using clinical vignettes showed that new alerts were more usable than traditional ones.This paper aimed to validate these results through a controlled and randomized experimental study with two branches (old vs. new design) in a real setting. We analyzed, quantitatively, every fired alert between April 2015 and September 2016. Finally, we performed user surveys and qualitative interviews to inquire about their satisfaction and perceptions.In real scenarios, user-centered design alerts were more usable, being more effective and satisfactory, but less efficient than traditional alerts. "Safe omission", as a new concept, emerged from our stratified analyses and interviews.

Formalizing Evidence Type Definitions for Drug-Drug Interaction Studies to Improve Evidence Base Curation

In this research we aim to demonstrate that an ontology-based system can categorize potential drug-drug interaction (PDDI) evidence items into complex types based on a small set of simple questions. Such a method could increase the transparency and reliability of PDDI evidence evaluation, while also reducing the variations in content and seriousness ratings present in PDDI knowledge bases. We extended the DIDEO ontology with 44 formal evidence type definitions. We then manually annotated the evidence types of 30 evidence items. We tested an RDF/OWL representation of answers to a small number of simple questions about each of these 30 evidence items and showed that automatic inference can determine the detailed evidence types based on this small number of simpler questions. These results show proof-of-concept for a decision support infrastructure that frees the evidence evaluator from mastering relatively complex written evidence type definitions.

KALIS - An eHealth System for Biomedical Risk Analysis of Drugs

BACKGROUND

In Germany, adverse drug reactions and events cause hospitalizations, which lead to numerous thousands of deaths and several million Euros in additional health costs annually.

OBJECTIVES

Approximately one in two deaths could be avoided by an appropriate system for risk analysis of drugs.

METHODS

The integration and storage of several data sources from life sciences are an ongoing need to address various questions with respect to drug therapy. A software architecture for data integration was implemented in order to build up a new data warehouse named KALIS-DWH, which includes pharmacological, biomolecular and patient-related data.

RESULTS

Based on this comprehensive KALIS-DWH, an eHealth system named KALIS for biomedical risk analysis of drugs was implemented. The task-specific modules of KALIS offer efficient algorithms for analyzing medication and supporting decision-making in drug therapy.

CONCLUSION

KALIS is meant to be a web-based information system for health professionals and researchers. KALIS provides comprehensive knowledge and modules for risk analysis of drugs, which can contribute to minimizing prescribing errors.

Implementation of an Outsourced Transnational Service of Clinical Decision Support System

The aim of this study is to describe the implementation and evaluation of an outsourced Clinical Decision Support Systems (CDSS) service of drug-drug interaction (DDI) alerts in an Uruguayan outpatient healthcare network. A cross-sectional study was developed. 1.5 alerts were triggered of every 1000 prescriptions. Clinicians accepted 44% of the total alerts. In conclusion, the implementation of CDSS was achievable.

An Experimental Comparison of a Co-Design Visualizing Personal Drug Information and Patient Information Leaflets: Usability Aspects

Providing patients with specific information about their own drugs can reduce unintentional misuse and improve compliance. Searching for information is time-consuming when information is not personalized and is written using medical vocabulary that is difficult for patients to understand. In this study we explored patient information needs regarding visualizing of drug information and interrelationships by conducting a total of four co-design workshops with patients, other users and pharmacists. We developed a prototype and drug ontology to support reasoning about drug interactions. We evaluated individual performance in finding information, understanding the drug interactions, and learning from the provided information in the prototype compared to using patient information leaflets (PILs). We concluded that interactive visualization of drug information helps individuals find information about drugs, their side effects and interactions more quickly and correctly compared to using PILs. Our study is limited to co-morbid patients with transient ischaemic attack with several chronic diseases.

Issues Pertaining To Daas

With the discovery of DAAs, the treatment of hepatitis C has improved a lot. But in this new era of DAAs several issues are also emerging. In this brief communication, we have tried to address the salient issues regarding DAAs.

New Alert Override Codes for the Drug Utilization Review System Derived from Outpatient Prescription Data from a Tertiary Teaching Hospital in Korea

Objectives

This paper proposes new alert override reason codes that are improvements on existing Drug Utilization Review (DUR) codes based on an analysis of DUR alert override cases in a tertiary medical institution.

Methods

Data were obtained from a tertiary teaching hospital covering the period from April 1, 2012 to January 15, 2013. We analyzed cases in which doctors had used the 11 overlapping prescription codes provided by the Health Insurance Review and Assessment Service (HIRA) or had provided free-text reasons.

Results

We identified 27,955 alert override cases. Among these, 7,772 (27.8%) utilized the HIRA codes, and 20,183 (72.2%) utilized free-text reasons. According to the free-text content analysis, 8,646 cases (42.8%) could be classified using the 11 HIRA codes, and 11,537 (57.2%) could not. In the unclassifiable cases, we identified the need for codes for "prescription relating to operation" and "emergency situations." Two overlapping prescription codes required removal because they were not used. Codes A, C, F, H, I, and J (for drug non-administration cases) explained surrounding situations in too much detail, making differentiation between them difficult. These 6 codes were merged into code J4: "patient was not taking/will not take the medications involved in the DDI." Of the 11 HIRA codes, 6 were merged into a single code, 2 were removed, and 2 were added, yielding 6 alert override codes. We could codify 23,550 (84.2%) alert override cases using these codes.

Conclusions

These new codes will facilitate the use of the drug–drug interactions alert override in the current DUR system. For further study, an appropriate evaluation should be conducted with prescribing clinicians.

The prevalence of major potential drug-drug interactions at a University health centre pharmacy in Jamaica

OBJECTIVE

To identify major potential drug-drug interactions (DDIs) on prescriptions filled at the University Health Centre Pharmacy, Mona Campus, Jamaica.

METHODS

This investigation utilised a cross-sectional analysis on all prescriptions with more than one drug that were filled at the Health Centre Pharmacy between November 2012 and February 2013. Potential DDIs were identified using the online Drug Interactions Checker database of Drugs.com.

RESULTS

During the period of the study, a total of 2814 prescriptions were analysed for potential DDIs. The prevalence of potential DDIs found during the study period was 49.82%. Major potential DDIs accounted for 4.7 % of the total number of interactions detected, while moderate potential DDIs and minor potential DDIs were 80.8 % and 14.5 % respectively. The three most frequently occurring major potential DDIs were amlodipine and simvastatin (n=46), amiloride and losartan (n=27) and amiloride and lisinopril (n=16).

CONCLUSION

This study has highlighted the need for educational initiatives to ensure that physicians and pharmacists collaborate in an effort to minimise the risks to the patients. These interactions are avoidable for the most part, as the use of online tools can facilitate the selection of therapeutic alternatives or guide decisions for closer patient monitoring and thus reduce the risks of adverse events.

Extreme bradycardia after first doses of sofosbuvir and daclatasvir in patients receiving amiodarone: 2 cases including a rechallenge

Sofosbuvir and daclatasvir are direct-acting antiviral drugs used to treat chronic hepatitis C virus infection. In 2015, the Food and Drug Administration and European Medical Agency warned that bradycardia could occur when amiodarone was administered in combination with sofosbuvir, but no case reports had been published. We report extreme bradycardia within 2 hrs after intake of sofosbuvir and daclatasvir by 2 patients receiving amiodarone. The first patient had a cardiac asystole 30 min after receiving sofosbuvir and daclatasvir. Amiodarone, sofosbuvir, and daclatasvir treatment were stopped; after 10 days, the cardiac evaluation was normal and patient was discharged. The second patient was taking amiodarone and propranolol; 2 hrs after receiving sofosbuvir and daclatasvir, he had an extreme sinus node dysfunction (heart rate of 27beats/min). Amiodarone and propranolol were stopped, but the patient continued receiving sofosbuvir and daclatasvir for 3 days and sinus bradycardia was recorded each day, 2 hrs after intake of these drugs. When he stopped taking the drugs, no bradycardia was observed. Administration of sofosbuvir and daclatasvir on day 13 induced bradycardia 2 hrs after intake. However, no bradycardia occurred following a rechallenge 8 weeks after the patient stopped taking amiodarone. These observations indicate that patients treated with amiodarone should be continuously monitored within the first 48 hrs following the initiation of sofosbuvir and daclatasvir.

Preserved pharmacokinetic exposure and distinct glycemic effects of insulin degludec and liraglutide in IDegLira, a fixed-ratio combination therapy

Insulin degludec/liraglutide (IDegLira) is a novel fixed-ratio combination of the basal insulin insulin degludec (IDeg) and liraglutide, a glucagon-like peptide-1 analog. The pharmacokinetics (PK) and pharmacodynamics of IDegLira were assessed versus its components. A single-dose, randomized, 4-period crossover clinical pharmacology study in healthy subjects compared the bioavailability of IDegLira with its monocomponents. Dose proportionality, covariate effects on exposure, and exposure-response for change in glycated hemoglobin were analyzed based on data from a randomized treat-to-target phase 3 study in subjects with type 2 diabetes. Overall, the PK properties of IDeg and liraglutide were preserved for IDegLira. Liraglutide exposure was lower when dosed as IDegLira but met the criterion for equivalence. No relevant deviations from dose proportionality for the IDegLira components were observed. Covariate effects on exposure were consistent with previous results. Glycemic response to IDegLira was larger than with IDeg or liraglutide alone, reflecting their distinct glucose-lowering effects throughout the dose/exposure range.

Differences of Reasons for Alert Overrides on Contraindicated Co-prescriptions by Admitting Department

OBJECTIVES

To reveal differences in drug-drug interaction (DDI) alerts and the reasons for alert overrides between admitting departments.

METHODS

A retrospective observational study was performed using longitudinal Electronic Health Record (EHR) data and information from an alert and logging system. Adult patients hospitalized in the emergency department (ED) and general ward (GW) during a 46-month period were included. For qualitative analyses, we manually reviewed all reasons for alert overrides, which were recorded as free text in the EHRs.

RESULTS

Among 14,780,519 prescriptions, 51,864 had alerts for DDIs (0.35%; 1.32% in the ED and 0.23% in the GW). The alert override rate was higher in the ED (94.0%) than in the GW (57.0%) (p < 0.001). In an analysis of the study population, including ED and GW patients, 'clinically irrelevant alert' (52.0%) was the most common reason for override, followed by 'benefit assessed to be greater than the risk' (31.1%) and 'others' (17.3%). The frequency of alert overrides was highest for anti-inflammatory and anti-rheumatic drugs (89%). In a sub-analysis of the population, 'clinically irrelevant alert' was the most common reason for alert overrides in the ED (69.3%), and 'benefit assessed to be greater than the risk' was the most common reason in the GW (61.4%).

CONCLUSIONS

We confirmed that the DDI alerts and the reasons for alert overrides differed by admitting department. Different strategies may be efficient for each admitting department.

Drug therapy yesterday, today and tomorrow, basic fundamentals for the non-scientist

DESCRIPTION

This overview of the evolution of drug development and the tools utilized by pharmacologists to ensure drug safety and efficacy provides solid insight into the drug development process, the potential for drug interactions and the difference between drugs and non-drug "natural" products.

AUDIENCE

This book is intended for the non-scientist, but is most applicable to the non-pharmacologist with a basic scientific background.

FEATURES

The book provides a basic history of medicinal agents and a good tutorial in the various terms and processes used in contemporary drug development to help the non-pharmacologist better understand all of the factors that must be considered when developing a therapeutic agent. It also explains in depth the effective use and potential perils of non-drug "natural" products. The material regarding the effect between the body and drugs may be difficult for an individual with no scientific background to understand; however, the awareness of drug interactions is an important one, the understanding of which would be beneficial for everyone.

ASSESSMENT

This book in an excellent tutorial, well thought through and methodical in its presentation and could be used for teaching curriculum for the non-pharmacologist with a scientific background.

Profile of drug interactions in hospitalized children

Introduction

The expected therapeutic response may be affected by the presence of drug interactions. With the high number of reports on new drug interactions, it has been difficult for health professionals to keep constantly updated. For this reason, computer systems have helped identify such interactions.

Objectives

To verify the rate and profile of drug interactions in medical prescriptions to hospitalized pediatric patients.

Methods

A descriptive study investigated prescriptions to hospitalized pediatric patients. The study included patients between 0 and 12 years old, containing 4 or more drugs in their prescriptions. The analysis of interaction and incompatibility possibilities in prescribed drugs used Micromedex / Drug-Reax® program.

Results

From 2005 to 2006, 3,170 patients were investigated, and 11,181 prescriptions were analyzed, a mean value of 3.5 prescriptions/patient. In total, 6,857 drug interactions were found, which corresponds to 1.9 interaction/prescription. Among them, relevance to ampicillin and gentamicin, found in 220 (3.2%) prescriptions. In total, 2,411 drug incompatibilities in via y were found, a mean value of 0.5/prescription, with emphasis on vancomycin and cefepime, found in 243 (10.0%) prescriptions.

Conclusion

The presence of drug interactions is a permanent risk in hospitals. This way, the utilization of computer programs, pharmacotherapy monitoring of patients and the pharmacist presence in the multidisciplinary team are some manners of contributing to hospitalized patients’ treatment.

Potential drug-drug and drug-condition interactions among fibromyalgia patients initiating pregabalin or duloxetine: prevalence and health care expenditure impact

OBJECTIVE

To quantify the prevalence of potential drug-drug/drug-condition interactions (DDI/DCI) among fibromyalgia patients initiating pregabalin or duloxetine, and to determine the impact of potential DDI/DCI on health care expenditures.

DESIGN

Retrospective cohort study.

SETTING

U.S. clinical practice, as reflected within a large administrative claims database.

SUBJECTS

Fibromyalgia patients newly initiating pregabalin or duloxetine between July 1, 2008 and October 1, 2010 (initiation date = index).

OUTCOME MEASURES

Potential DDI measured using clinical software that identifies co-prescription of medications that potentially interact with pregabalin or duloxetine. Potential DCI, drawn from the contraindications and warnings and precautions sections of pregabalin and duloxetine prescribing information, measured using administrative claims-based algorithms. All-cause health care expenditures measured throughout a 6-month postindex period. Analyses included univariate, bivariate, and multivariable statistical approaches.

RESULTS

Seven thousand seven hundred fifty-one pregabalin and 7,785 duloxetine initiators were selected for study: mean age 49 years, 88% female. Only 1.4% of pregabalin initiators had ≥1 potential pregabalin DCI; none had potential pregabalin DDI. In contrast, 67% of duloxetine initiators had potential duloxetine DDI/DCI, driven mostly by potential duloxetine DDI (62% of duloxetine initiators). Compared between pregabalin and duloxetine initiators, differences in the prevalence of potential DDI/DCI were statistically significant (P < 0.001). Multivariable analyses indicated that, among duloxetine initiators, those with potential duloxetine DDI/DCI had postinitiation health care expenditures that were $670 higher (P < 0.001) than those without potential duloxetine DDI/DCI. Among pregabalin initiators, potential pregabalin DDI/DCI were not associated with health care expenditures.

CONCLUSIONS

Among fibromyalgia patients initiating pregabalin or duloxetine, potential duloxetine DDI could be highly prevalent. Among duloxetine initiators, potential duloxetine DDI/DCI were significantly associated with increased health care expenditures.

Drug-drug interactions and their predictors: Results from Indian elderly inpatients

Background

In view of the multiple co-morbidities, the elderly patients receiving drugs are prone to suffer with drug interactions since they receive a greater number of drugs.

Objective

The study was undertaken to determine the prevalence of drug interactions, as well as their predictors.

Methods

The prescriptions of a total of 1510 inpatients were collected prospectively for 1.5 years from inpatients wards of public tertiary care teaching hospital. All the prescriptions were checked for drug interactions using the Micromedex® Drug-Reax database-2010 and Stockley’s Drug Interactions. Regression analyses sought to determine predictors for the drug interaction.

Results

The patients, with the average age of 67.2 ±0.2 years, were prescribed an average of 9.15 ±0.03 medications. It was found that out of 1510 prescriptions of inpatients, 126 (8.3%) prescriptions had one or more than one drug interaction. All the identified interactions were severe in nature. The top most interacting drugs were acetylsalicylic acid and anticoagulant (n=59). The second top most interacting drug combination was clopidogrel and proton pump inhibitors (n=51). The most commonly involved drugs in interactions were C (cardiovascular system) and A (alimentary tract and metabolism). Using multivariate binary logistic regression, multiple drugs (Odds Ratio=4.5; 95% Confidence Interval: - 2.38 -9.47) and multiple diagnoses (Odds Ratio=2.6; 95%CI: -1.40 -5.57) were found to be significant predictors for drug interaction.

Conclusions

The results of this study substantiate the occurrence of severe drug interactions among Indian elderly inpatients. In order to provide safer pharmaceutical care, the active involvement of clinical pharmacists is a potential option.

Reversible dysphasia and statins

This paper presents a case of reversible dysphasia occurring in a patient prescribed atorvastatin in combination with indapamide. A milder dysphasia recurred with the prescription of rosuvastatin and was documented on clinical examination. This resolved following cessation of rosuvastatin. The case highlights both a need for a wider understanding of potential drug interactions through the CYP 450 system and for an increased awareness, questioning and reporting of drug side-effects.

Analysis of potential interactions between warfarin and prescriptions in Estonian outpatients aged 50 years or more

In Estonia, warfarin is widely prescribed by general practitioners to prevent and treat thromboembolic diseases. To date, there has been no systematic analysis of the potential risk of warfarin interactions with other drugs in the outpatient population.

Objective

The aim of the study was to analyze the incidence of potential interactions in prescription schemes in Estonia in a cohort of outpatients receiving warfarin treatment.

Methods

The retrospective study population included 203,646 outpatients aged 50 years or older of whom 7,175 received warfarin therapy. Patients who had used at least one prescription drug for a minimum period of 7 days concomitantly with warfarin were analyzed. Potential drug interactions were analyzed using Epocrates online, Stockley's Drug Interactions and domestic drug interaction databases.

Results

The average number of drugs used concomitantly with warfarin was 4.8 (SD=1.9) (males: 4.7 SD=2.0, females: 4.9 SD=2.0). No potential interactions in treatment regimens were found in 38% of patients, one potential interaction was observed in 29% and two or more potential interactions were observed in 33% of patients. The mean number of all potential interactions was 1.2 per patient and about the same in men and women. Potential interactions were associated with the number of drugs. Warfarin-related interactions were detected in 57% of patients, and the number of interactions related to warfarin per patient varied from 1 to 5. Most frequent were use of warfarin with NSAIDs (14%), followed by simvastatin (9%) and amiodarone (7%).

Conclusions

This study shows that 57% of outpatients in Estonia receiving warfarin have drugs potentially interacting with warfarin in their treatment schemes. Most interactions (14%) with warfarin are associated with the prescription of NSAIDs.