Toyota T, Kitamura Y, Araki H, Sadakane N, Futagami K, Furuno K, Gomita Y
Department of Hospital Pharmacy, Okayama University Medical School, 2-5-1, Shikata-cho, Okayama 700-8558, Japan.
Pharmacol Biochem Behav. 2001 Oct-Nov;70(2-3):375-9. doi: 10.1016/s0091-3057(01)00617-7.
The influence of oral adsorbent AST-120 (Kremezin) on the anticonvulsive effect and pharmacokinetics of zonisamide was investigated. Oral administration of zonisamide (50 mg/kg) blocked the appearance of the tonic extension induced by maximal electroshock seizure. This effect of zonisamide was inhibited by the oral coadministration of AST-120 (5 g/kg). In pharmacokinetics study, the serum zonisamide concentration after coadministration of zonisamide and AST-120 was significantly lower than that of single administration of zonisamide. However, the anticonvulsive effect of zonisamide was not affected by the administration of AST-120 1.5 h after zonisamide administration. In this condition, the serum zonisamide concentration was not changed. In the in vitro study, AST-120 completely adsorbed zonisamide. These findings suggest that when AST-120 is administered concurrently with zonisamide, a significant inhibition of the anticonvulsive effect of zonisamide occurs, and the decrease in serum zonisamide concentration by the adsorption effect of AST-120 is related to this phenomenon.
