Drug utilization pattern of anti-epileptic drugs: a pharmacoepidemiologic study in Oman

Role of human leukocyte antigen in anti-epileptic drugs-induced Stevens-Johnson Syndrome/toxic epidermal necrolysis: A meta-analysis

PURPOSE

Antiepileptic drugs (AEDs) are extensively used to manage epilepsy and other comorbidities associated with seizures. Human Leukocyte Antigen (HLA) has a strong association with AED-induced severe cutaneous adverse drug reactions.

OBJECTIVE

We aimed to perform a systematic review and meta-analysis to identify, critically evaluate, and synthesize the best possible evidence on HLA-associated AED-induced Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN).

METHODS

MEDLINE/PubMed, Scopus, and the Cochrane Library were searched for literature from inception up to July 2022. We included case control studies analyzing association between HLA and AED-induced SJS/TEN. We assessed the studies' risk of bias in using Quality of genetic studies (Q-genie) tool. Outcomes focused on association (risk) between HLA and AED-induced SJS/TEN. The estimated risk was presented in the form of odds ratio (OR).

RESULTS

We included 37 studies (51,422 participants; 7027 cases and 44,395 controls). There was a significantly higher risk of Carbamazepine-induced SJS/TEN with HLA-A (OR: 1.50; 95% CI: 1.03 to 2.17), HLA-B (OR: 1.94; 95% CI: 1.45 to 2.58), HLA-C (OR: 7.83; 95% CI: 4.72 to 12.98), and HLA-DRB1 (OR: 2.82; 95% CI: 1.94 to 4.12). Lamotrigine-induced SJS/TEN posed a higher risk with HLA-A (OR: 2.38; 95% CI: 1.26 to 4.46) and HLA-B (OR: 2.79; 95% CI: 1.75 to 4.46). Phenytoin-induced SJS/TEN showed a higher risk with HLA-A (OR: 3.47; 95% CI: 2.17 to 5.56), HLA-B (OR: 1.72; 95% CI: 1.38 to 2.15), and HLA-C (OR: 2.92; 95% CI: 1.77 to 4.83). Phenobarbital-induced SJS/TEN had a higher risk with HLA-A (OR: 6.98; 95% CI: 1.81 to 26.84), HLA-B (OR: 2.40; 95% CI: 1.39 to 4.17), and HLA-C (OR: 3.37; 95% CI: 1.03 to 11.01). Zonisamide-induced SJS/TEN was significantly associated with HLA-A*02:07 (OR: 9.77; 95% CI: 3.07 to 31.1), HLA-B*46:01 (OR: 6.73; 95% CI: 2.12 to 21.36), and HLA-DRB1×08:03 (OR: 3.78; 95% CI: 1.20 to 11.97). All other alleles of HLA were observed to have a non-significant association with AED-induced SJS/TEN. All included studies were of good quality, with a score of >50 and a mean score of 54.96 out of 77.

CONCLUSION

Our study showed a significant association between few variants of HLA alleles and AED-induced SJS/TEN. Evidences from our study could help in population-based studies and in implementation of individualized treatment regimens. These findings could be part of translational research helping in precision therapy.

Sociodemographic, Rationale Drug Use of Antiepileptic Drugs among Pediatric Patients with Epilepsy: A Prospective Study at a Tertiary Care Hospital

Background   Drug utilization studies are important and considered as a potential tool for the evaluation of health care systems. The goal of drug utilization research studies should be to assess whether drug therapy is rational or not.

Objective   The main aim of this article is to analyze the different types of epilepsy and their drug utilization pattern in children with epilepsy at the Department of Pediatrics and evaluate the extent of older and newer antiepileptic drugs (AEDs), either as monotherapy or polytherapy in pediatric age groups.

Materials and Methods   To look into the sociodemographic profile of children with epilepsy, the type of epilepsy was diagnosed along with drug utilization pattern in children attending both outpatient and inpatient department of pediatrics. Demographic details were collected according to modified Kuppuswamy scale. Disease characteristics such as type of epilepsy, onset, duration, time since last attack, family history, comorbid conditions, monotherapy/polytherapy, dose, and duration of treatment were noted. Investigations such as electroencephalography, magnetic resonance imaging, and computed tomographic scan if any were recorded.

Results   In this pilot study, we have 100 patients, younger than 18 years, with confirmed cases of epilepsy, receiving AEDs either monotherapy or polytherapy. Male predominance was 56%, and 60% were from rural areas and 40% were from urban areas. As per the modified Kuppuswamy scale, we analyzed socioeconomic class of these 100 patients and found that 40% belong to lower-middle-class family. Nearly 51% were diagnosed with generalized tonic clonic seizures, 30% were with febrile seizures, while focal, partial, absence, and myoclonic seizures, and hot water epilepsy were less in percentage. Almost 83% received monotherapy, while only 17% received polytherapy. Among monotherapy, 51.80% received older AEDs and 48.20% received newer drugs.

Conclusion   Although epilepsy can be controlled and managed effectively with older AEDs, an experience in management with newer AEDs is required to offer an additional advantage to patients to have better safety profile.

Medication adherence and adverse effect profile of antiepileptic drugs in Nigerian patients with epilepsy

Aim: Medication adherence remains a major challenge among patients with epilepsy (PWE) with the adverse effect profile of antiepileptic drugs (AEDs) as one of its main drivers. Methods: This was a cross-sectional questionnaire-based study among PWE in selected Nigerian tertiary healthcare facilities using the Morisky Medication Adherence Scale and the Liverpool Adverse Effect Profile (LAEP). Results: 126 PWE from four tertiary healthcare facilities were included in this study comprising of 59 (46.8%) males and 67 (53.2%) females. Carbamazepine (104/70.7%), sodium valproate (23/15.6%) and phenytoin (11/7.5%) were the most commonly prescribed AEDs. Using the Morisky Medication Adherence Scale, 17.2, 38.3 and 44.5% of patients were classified as having high, medium and low adherence, respectively. The mean LAEP score was 23.69 ± 6.07. The most common reported adverse effects among respondents were tiredness (30.4%) and headache (22.5%). Conclusion: Medication adherence to AED was poor among patients in this study.

Antiepileptic drug utilization in Bangladesh: experience from Dhaka Medical College Hospital

BACKGROUND

Epilepsy is a common health problem which carries a huge medical social psychological and economic impact for a developing country. The aim of this hospital-based study was to get an insight into the effectiveness and tolerability of low cost antiepileptic drugs (AEDs) in Bangladeshi people with epilepsy.

METHODS

This retrospective chart review was done from hospital records in weekly Epilepsy outdoor clinic of Department of Neurology, Dhaka Medical College Hospital (DMCH) from October 1998 to February 2013. A total of 854 epilepsy patients met the eligibility criteria (had a complete record of two years of follow up data) from hospital database. A checklist was used to take demographics (age and gender), epilepsy treatment and adverse event related data. At least two years of follow up data were considered for analysis.

RESULTS

Out of 854 patients selected, majority of the patients attending outdoor clinic were >11-30 years age group (55.2%) with a mean age of 20.3 ± 9 years and with a male (53%) predominance. Focal epilepsy were more common (53%), among whom secondary generalized epilepsy was the most frequent diagnosis (67%) followed by complex partial seizure (21%). Among those with Idiopathic Generalized Epilepsy (46%), generalized tonic clonic seizure was encountered in 74% and absence seizure was observed in 13%. The number of patients on monotherapy and dual AED therapy were 67% and 24% respectively and polytherapy (i.e. >3 AEDs) was used only in 9%. CBZ (67%) was the most frequently prescribed AED, followed by VPA (43%), PHB (17%), and PHT (8%). CBZ was prescribed in 37% patients as monotherapy followed by VPA in 21% and PHB in 8% patients. Newer generation drugs eg lemotrigine and topiramate were used only as add on therapy in combination with CBZ and VPA in only 2% patients. The treatment retention rates over the follow up period for the AEDs in monotherapy varied between 86 and 91% and were highest for CBZ, followed by VPA. Most of the combination regimens had a treatment retention rate of 100%. The effectiveness of AED in terms of reduction of seizure frequency was highest for PHT (100%) and PHB (98%) followed by CBZ (96%) and VPA (95%). PHB and PHT were the cheapest of all AEDs (42 I$ and 56 I$/ year respectively). The costs of VPA and CBZ were two times and LTG and TOP were six to eight times higher. Adverse drug reaction (ADR) were observed among 140 (24.5%) of those with monotherapy. PHT (64%) was the most common drug to cause ADR, CBZ was at the bottom of the list to cause adverse effect (11.6%). VPA and PHB caused weight gain commonly. Adjustment of drug dose or withdrawal due to ADRs was necessary in 39% with PHT and 26% with PHB.

CONCLUSION

Though PHT and PHB are cheapest and efficacious among all, CBZ and VPA are less costly, effective and well tolerated drug for seizure control in context of Bangladesh.

Evaluation of unlicensed and off-label antiepileptic drugs prescribed to children: Brazilian Regulatory Agency versus FDA

BACKGROUND

Epileptic seizures are neurological disorders common in children; 4 to 10% of under 16-year olds have suffered at least one seizure. Antiepileptic drugs represent the basis of treatment for the majority of patients, but many of the drugs prescribed to pediatrics are used unlicensed and off-label.

OBJECTIVE

To analyze the prevalence of use of unlicensed and off-label antiepileptic drugs, by the pediatric population, according to the Food and Drug Administration and the Brazilian National Health Surveillance Agency. Setting General Hospital of the Faculty of Medicine at Ribeirão Preto, Brazil.

METHODS

A cross-sectional, retrospective and observational study was carried out. The daily prescriptions of children up to 12 years of age were collected for the analysis of antiepileptic drug use. Data of the registration number, sex, age, reason hospitalized, unit where hospitalized, drug prescribed, dosage, route and administration frequency were collected.

MAIN OUTCOME MEASURE

Antiepileptic drugs prescribed for children were classified as unlicensed and off-label according to the term of the product's license registered in the Food and Drug Administration and the Brazilian National Health Surveillance Agency.

RESULTS

Of the 6,637 pediatric patients identified during the study period, 583 (9.0%) received at least one antiepileptic drug. The most used antiepileptic drugs were phenobarbital, phenytoin, carbamazepine, valproic acid and clonazepam. As expected, the number of pharmaceutical dosage form classified as unlicensed or off-label was high in both agencies, but distinct between the two. The number of patients (n = 287) using unlicensed drugs was similar in the two agencies, but the use of off-label drugs was higher according to the analysis carried out by the North American agency (40.5%).

CONCLUSIONS

Old-generation antiepileptic drugs are widely prescribed to children. The results found for the use of off-label drugs demonstrate the absence of uniformity in action between the agencies and a lack of integration between the studies carried out. Although legislation on the licensing of drugs aims to protect the patients from drugs that have not been scientifically evaluated, the scarcity of data about the safety of the therapeutic resources obliges the doctors to prescribe unlicensed and off-label antiepileptic drugs to the pediatric population.

Utilization patterns of antiepileptic drugs among adult epileptic patients at a tertiary hospital in Oman

Objectives

To describe utilization patterns of antiepileptic drugs (AEDs) among adult epileptic patients at a tertiary hospital in Oman.

Methods

Data were collected retrospectively from January 2006 to December 2009. The study included all adult (>18 years) epileptic patients on AEDs and followed up at a neurology clinic at Sultan Qaboos University Hospital in Oman. All reported therapeutic drug monitoring (TDM) requests for serum AED concentrations were also collected. Institutional ethical approval was sought and obtained.

Key findings

The study included a total of 372 patients with a mean age of 34 ± 15 years. Monotherapy AEDs accounted for 53% of the prescriptions, whereas polytherapy with two or three AED combinations accounted for 27% and 20% respectively. The most frequently prescribed AED was sodium valproate (27%) followed by carbamazepine (23%). The commonly prescribed AED combinations were sodium valproate with clonazepam (12%) followed by sodium valproate with lamotrigine (12%). Evaluation of 574 TDM requests for three AEDs showed that 57% of carbamazepine, 78% of phenytoin and 54% of valproic acid requests were either above or below the recommended therapeutic threshold. Most of these requests were ordered from the hospital's emergency department for suspected insufficient serum concentrations.

Conclusions

Antiepileptic drug monotherapy is still the most frequently employed therapeutic strategy in adult patients with epilepsy in keeping with the standard therapeutic guidelines. Sodium valproate is commonly used for different types of seizures reflecting its wide spectrum of anticonvulsant potential. Newer AED utilizations are becoming increasingly popular in our subjects particularly as add-on with other standard AEDs.

Factors associated with nonbenzodiazepine antiepileptic drug intoxication: analysis of 9,809 registered cases of drug poisoning

PURPOSE

Antiepileptic drug (AED) intoxications are common due in part to wide clinical application and availability. Because AEDs usually depress central nervous system function, overdosing may be potentially life-threatening or lead to a range of adverse outcomes. The aim of this study was to identify risk factors for nonbenzodiazepine AED (NBAED) intoxication.

METHODS

In this cross-sectional study, all consecutive adult and adolescent (>12 years old) poisoned patients who presented to the Loghman-Hakim Poison Hospital (LHPH) during a 6-month period were evaluated. Patients with NBAED intoxication were identified and compared to a control group of those other pharmaceutical intoxications. The risk factors for AED intoxication were identified using univariate analyses and multivariate modeling.

RESULTS

Among 9,809 cases of pharmaceutical agent overdose, there were 474 cases (4.8%) with NBAED intoxication. Mean age of the subjects was 24.5 +/- 8.9 years. The most frequent NBAED was carbamazepine (n = 117), followed by phenobarbital (n = 77) and sodium valproate (n = 51). The most frequent motivation was intentional intoxication (95.3%). Multivariate analysis revealed that presence of medical disorders, a history of psychological events, and loneliness were associated with AED intoxication, whereas educational level had a protective effect. There was no association between previous history of parasuicide, sex, age, occupation status, and AED intoxication.

DISCUSSION

In conclusion, this study showed that the majority of AED intoxications are due to deliberate self poisoning. The presence of psychological events, medical disorders, and loneliness are risk factors for AED intoxication, whereas higher education level has a protective effect.

Efficacy and tolerability of antiepileptic drugs in an Omani epileptic population

OBJECTIVE

The aim of this hospital-based study is to get an insight into the efficacy and tolerability of antiepileptic drugs (AED) in Omani epileptic patients.

PATIENTS AND METHODS

All Omani patients (aged 14 years and above) suffering from epileptic seizures for at least 2 years and followed-up by board-certified neurologists in Sultan Qaboos University Hospital (SQUH) were evaluated. The treatment retention rate since first visit at SQUH and over the last 2 years was used as primary efficacy measure of AED therapy. Change in seizure-frequency and side effect profiles were also assessed.

RESULTS

In this population of 203 confirmed epileptic patients, generalized tonic-clonic (40%) and partial seizures (39%) were most commonly observed, idiopathic/cryptogenic origin (81%) being the most frequent encountered origin. Sixty one percent of the patients were controlled with an AED in monotherapy and overall 34% of patients could be successfully maintained on monotherapy during the whole follow-up period at SQUH (median 6 years). The treatment retention rates for carbamazepine (CBZ) at a daily dose of 400-600 mg, sodium valproate (VPA) at a daily dose of 500-1000 mg, and phenytoin (PHT) at a daily dose of 300 mg, in monotherapy over the total follow-up period was 51, 50, and 21%, respectively. In contrast, over the last 2 years these rates were highest for VPA (91%) followed by CBZ (83%) and PHT (73%). Adverse drug reactions were recorded in 67% of patients, and were most commonly encountered with VPA.

CONCLUSIONS

Despite a higher adverse effect profile for VPA, long-term treatment with CBZ and VPA appeared to be equally effective in terms of treatment retention rates and seizure control.

Estimation of Population Pharmacokinetic Parameters of Free-Phenytoin in Adult Epileptic Patients

BACKGROUND

Serum concentrations of free-phenytoin (F-PHT) obtained in adult epileptic patients receiving PHT in monotherapy were analyzed to estimate the Michaelis-Menten pharmacokinetic parameters.

METHODS

Steady-state F-PHT serum concentrations, PHT dosing history, and associated information were collected prospectively. The maximum metabolic rate (Vm) and Michaelis-Menten constant (Km) of F-PHT and their interindividual variability data were estimated using nonlinear mixed effects modeling (NONMEM).

RESULTS

Twenty-nine patients with two or more available steady-state F-PHT serum concentrations (total of 63 dose/serum concentration pairs) met the inclusion criteria. Patients were taking PHT (100-500 mg/day) in monotherapy. The population estimates of F-PHT for Vm and Km were 9.1 mg/kg/day and 7.3 mg/L, respectively. The model was prospectively evaluated in a small group (seven) of additional patients.

CONCLUSIONS

The recommended daily dose in this population to achieve a F-PHT concentration of 1.5 mg/L is 6.1 mg/kg.