Pharmacokinetic interactions of Mentat with carbamazepine and phenytoin

In the present study, Mentat, a herbomineral psychotropic preparation, was studied for its pharmacokinetic interaction with the commonly used anti-epileptic drugs, carbamazepine and phenytoin. The interaction of carbamazepine and phenytoin with Mentat was studied in rabbits. Thirty two rabbits were divided into four groups of eight each. Animals of Group I were treated with carbamazepine (50 mg/kg b.wt. p.o.), Group II were treated with carbamazepine (50 mg/kg b.wt. p.o.) + Mentat (500 mg/kg b.wt. p.o.), Group III were treated with phenytoin (50 mg/kg b.wt. p.o.) and Group IV were treated with phenytoin (50 mg/kg b.wt. p.o.) + Mentat (500 mg/kg b.wt. p.o.) for a period of 8 days. On day 0 and day 8, plasma carbamazepine and phenytoin levels were estimated at different time intervals. A simultaneous treatment with Mentat resulted in a significant increase in plasma AUC of carbamazepine as well as phenytoin as compared to carbamazepine or phenytoin alone. Cmax and Tmax of carbamazepine and phenytoin also were evaluated. The results suggest that co-administration of Mentat could improve the effectiveness of anti-epileptic drugs due to the increased bioavailability of the latter. However, this has to be done with critical medical supervision to avoid any toxic reactions and preferably with therapeutic drug monitoring (TDM) which could also help in dose optimization.