Potentiation of anticonvulsant activity of phenytoin by calcium channel blockers (verapamil and amlodipine) against maximal electroshock seizures in rats

Background: The objective of this work was to study the anticonvulsant activity of calcium channel blockers verapamil and amlodipine and their interaction with an established antiepileptic drug diphenylhydantoin (DPH) in experimental model of epilepsy in albino rats. Methods: Maximal electroshock (MES) convulsions were induced by electroconvulsiometer and different phases of MES were noted in control and drug treated groups. Effect of different doses of verapamil (dose-5, 10 and 15 mg/kg), amlodipine (dose-2.5, 3 and 3.5 mg/kg) and DPH (dose-0.5 and 1 mg/100 g) on MES was studied. Finally, effect of combined treatment consisting of non-protective dose of DPH with different doses of verapamil and amlodipine were also studied on MES induced seizures. Results: Combination of non-protective dose (0.5 mg/100 g) of DPH with all the three doses of verapamil and amlodipine offered significant protection against MES induced seizures. Conclusions: From the present investigation, it may be concluded that the dose of DPH may be reduced in an antiepileptic individual who is on verapamil and amlodipine therapy.