Anticonvulsant profile of nimodipine and nitrendipine against pentylenetetrazole induced seizures in rats

Abstract

The activity of nimodipine and nitrendipine against pentylenetetrazole (PTZ) induced seizures in Albino rats was studied alone and in combination with valproate. The median effective dose [ED₅₀] of valproate, nimodipine and nitrendipine were initially determined. All the 3 drugs were injected ip 30 min before the induction of seizures. Seizures were induced by PTZ 85mg/kg ip, and subsequently the effect of combining ED₅₀ doses of nimodipine and nitrendipine with ED₅₀dose of valproate was evaluated. ED₅₀ of valproate and nitrendipine were 129 and 2.5 mg/kg respecti vely. ED₅₀ of nimodipine could not be established since a dose-response relationship was not obtained. Hence, for the purpose of combination studies, 4mg/kg of nimodipine was used. Both nimodipine (4mg/kg) and nitrendipine (2.5mg/kg) decreased the ED₅₀of valproate from 129 to 40mg/kg. Both nimodipine and nitrendipine potentiate the activity of valproate against PTZ induced seizures and can be considered as potential adjuvant anticonvulsants which merit further study.