Adverse Reactions to Antiepileptic Drugs in Epileptic Outpatients: A Cross-Sectional Study in Iran

Objective: To evaluate the pattern and possible risk factors of adverse reactions to antiepileptic drugs (AEDs) in epileptic outpatients in Iran. Methods: We conducted a cross-sectional study for a period of 1 year on epileptic outpatients under antiepileptic therapy. All present adverse drug reactions (ADRs) to antiepileptics and their clinical and paraclinical characteristics were recorded. Causality assessment was performed by the Naranjo algorithm. Seriousness of ADRs was assessed by the World Health Organization's definition. Schumock and Thornton questionnaire was applied to determine the preventability of ADRs. Statistical-descriptive analyses were performed. Results: A total of 1055 adverse reactions to AEDs were recorded from 201 epileptic outpatients. Their mean +/- SD age was 28.63 +/- 15.06 years. The most frequent detected adverse reactions to AEDs were sedation (7.29%) and amnesia (6.35%). According to the Naranjo algorithm, 604 (57.25%) ADRs were possible. The rate of preventable ADRs was 57%. Only 8 (0.76%) ADRs were identified as serious. No statistically significant association was found between the number of ADRs and age, sex, type of epilepsy, and AED generation (P > 0.05). In contrast, polytherapy was associated with more ADRs than monotherapy (P = 0.039). According to multivariate logistic regression analysis, females were at a higher risk of experiencing an adverse reaction to AEDs than males (odds ratio, 3.676; 95% confidence interval, 1.198-11.283; P = 0.023). Conclusion: Adverse reactions to AEDs were very common among epileptic outpatients. The female sex was identified as a risk factor for experiencing an ADR.