Comparative Evaluation of Efficacy and Safety of Monotherapy with Carbamazepine and Phenytoin In Epilepsy : A Meta-Analysis

Abstract

Aims and Objectives To review and analyse statistically the evidence from existing randomised controlled trials. To compare the efficacy and safety of carbamazepine and phenytoin when used as monotherapy treatments. To assess the effectiveness of the drug at controlling seizures and to evaluate tolerability with regard to side effects of these drugs. Methodology: A systemic review with the comparative evaluation of efficacy and safety of monotherapy with Carbamazepine and Phenytoin in epilepsy was carried out. Seven studies with Randomised Controlled Trials of carbamazepine and phenytoin as monotherapy were taken up for Meta Analysis based on the inclusion and exclusion criteria. Time to withdrawal of allocated treatment (retention time) was chosen as the primary outcome. Secondary outcomes included Time to achieve 12-month remission (seizure-free period), Time to achieve six-month remission (seizure-free period), Time to first seizure post-randomisation, Adverse events (including adverse events relating to treatment withdrawal. The data was entered in the MedCalc Statistical Software version 17.5.5 and analysed. The principal summary measure were the Odd’s Ratio And Hazard Ratio (HR) (at 95% Confidence Interval). Funnel Plot and Forest Plot were plotted. Results: The overall pooled odd‘s ratio for the primary outcome (for 862 participants) was 0.882(fixed effect model) and 0.877(random effect model) (95% confidence interval (CI)0.63 to 1.22, P = 0.3643). The P value was 0.3643 which proved the statistically insignificant difference in the efficacy of the two drugs(0.05 is considered as significant p value). As for the adverse effects ; rash, dysmorphic and idiosyncratic side effects include gum hypertrophy , hirsutism , acne etc. are more frequently associated with phenytoin. Drowsiness, Tiredness, Fatigue and sedation are more associated with carbamazepine as compared to phenytoin. The overall pooled odd’s ratio for “Time to achieve 6 month remission” (for 232 participants) was 1.232(fixed) and 1.272(random) (95% confidence interval (CI) 0.732 to 2.073(fixed), P = 0.0910), indicating an advantage for phenytoin for the 6 month remission outcome. Conclusion: The study concluded that there was no statistically significant difference achieved between the two treatment arms. Hence the neurophysician is compelled to rely on the individual patient characteristics for dispensing the drug. Hence the study provides a robust evidence that the two treatments are equally efficacious.