Inovelon Drug Interactions

Effects of INOVELON on other AEDs: Population pharmacokinetic analysis of average concentration at steady state of carbamazepine, lamotrigine, phenobarbital, phenytoin, topiramate, and valproate showed that typical rufinamide C_avss levels had little effect on the pharmacokinetics of other AEDs. Any effects, when they occur, have been more marked in the pediatric population.
Table 7 summarizes the drug-drug interactions of INOVELON with other AEDs. (See Table 7.)

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Phenytoin: The decrease in clearance of phenytoin estimated at typical levels of rufinamide (C_avss 15 μg/mL) is predicted to increase plasma levels of phenytoin by 7 to 21%. As phenytoin is known to have non-linear pharmacokinetics (clearance becomes saturated at higher doses), it is possible that exposure will be greater than the model prediction.
Effects of Other AEDs on INOVELON: Potent cytochrome P450 enzyme inducers, such as carbamazepine, phenytoin, primidone, and phenobarbital, appear to increase the clearance of INOVELON (see Table 7). Given that the majority of clearance of INOVELON is via a non-CYP-dependent route, the observed decreases in blood levels seen with carbamazepine, phenytoin, phenobarbital, and primidone are unlikely to be entirely attributable to induction of a P450 enzyme. Other factors explaining this interaction are not understood. Any effects, where they occurred, were likely to be more marked in the pediatric population.
Valproate: Patients stabilized on INOVELON before being prescribed valproate should begin valproate therapy at a low dose, and titrate to a clinically effective dose. Similarly, patients on valproate should begin at a INOVELON dose lower than 10 mg/kg per day (pediatric patients) or 400 mg per day (adults) (see Dosage & Administration, Pharmacology under Actions).
Effects of INOVELON on Hormonal Contraceptives: Female patients of childbearing age should be warned that the concurrent use of INOVELON with hormonal contraceptives may render this method of contraception less effective. Additional non-hormonal forms of contraception are recommended when using INOVELON (see Pharmacology under Actions).