Isobolographically additive anticonvulsant activity between Centella asiatica's ethyl acetate fraction and some antiepileptic drugs.

OBJECTIVE: To investigate interaction between orally given Centella asiatica's ethyl acetate fraction (EACA) and intraperitoneally administered antiepileptic drugs (AEDs), namely, phenytoin, valproate and gabapentin. MATERIAL AND METHOD: Isobolographic analysis was used to evaluate the interaction between EACA and AEDs in terms of protection of mice in the pentylenetetrazole test. Rotarod test was used to evaluate neurotoxicity. RESULTS: When given alone, the median effective dose of phenytoin, valproate and gabapentin were found to be 13, 104, and 310 mg/kg BW, respectively, whereas the corresponding values in the presence of EACA were 5, 29 and 79 mg/kg BW. Together with isobolographic analysis, the results obtained indicated an additive effect among all combinations tested. In relation to neurotoxicity, combination of gabapentin and EACA demonstrated a broader margin between the effective dose and the neurotoxic dose while the other two combinations did not. CONCLUSION: The present finding suggested a potential of Centella asiatica to be developed as an adjunctive medication for epileptic patients.

Oxcarbazepine as add-on therapy in Thai epileptic patients with refractory partial seizures.

OBJECTIVES: To evaluate efficacy and safety of oxcarbazepine (OXC) as add-on therapy in Thai refractory epileptic patients. MATERIAL AND METHOD: A randomized, double-blind clinical trial was conducted in outpatients of the Epilepsy Clinic of Phramongkutklao Hospital. OXC in the doses of 600 or 1200 mg/d were added to 39 refractory epileptic patients with the median baseline seizure frequency of at least 2 per 28 days. RESULTS: Of 35 patients who completed the 98-day treatment period, 4 became seizure free. A reduction in median seizure frequency of 47% and 58% was observed in patients in the 600 and 1,200 mg OXC/d groups, respectively. Among them, 44% and 53% demonstrated > or = 50% reduction in median seizure frequency. About 85% of patients in each group reported one or more mild to moderate adverse events. CONCLUSION: OXC in the doses of 600 and 1200 mg/d appear to be safe and effective as adjunctive therapy in Thai refractory epileptic patients. Further studies are needed to confirm its long-term efficacy and tolerability.