Effects of chronic administration of gabapentin and carbamazepine on the histomorphology of the hippocampus and striatum

BACKGROUND: Antiepileptic drugs used to avert epileptic seizures necessitate prolonged duration for improved efficacy and could induce some side effects. PURPOSE: The present study investigated the effect of chronic administration of two common antiepileptic drugs – gabapentin and carbamazepine, on the histomorphology of the hippocampus and striatum in adult rats. METHODS: 25 adult male Wistar rats were grouped randomly into 5 groups. 3 groups were administered either therapeutic doses of gabapentin (16 mg/kg) or carbamazepine (20 mg/kg) or sub-therapeutic dose of gabapentin plus carbamazepine (8 + 10 mg/kg). To confirm anticonvulsant effects, these animals were kindled for seizures at sub-maximal electroshock. Appropriate negative and positive controls were given normal saline. At the end of treatment, brain tissues were obtained and processed for histological procedures. RESULTS: The study confirm significant decrease (P<0.001) in convulsion parameters tonic flexion, tonic extension and clonic convulsion, between drug treated groups and electroshock control. Histological studies revealed significant increase (p<0.001) in neurons showing features of degeneration in the hippocampus, for drug treated groups as compared to normal and electroshock control. Also, drug treatment reduced nissl activity in both hippocampus and striatum. CONCLUSION: Chronic administration of gabapentin and carbamazepine may cause increase in neurodegenerative changes in the adult brain.