Efavirenz, lamivudin ve tenofovir ve Valproik asit etkileşimi

Hepatic enzyme-inducing drugs (e.g., phenytoin, carbamazepine, phenobarbital, primidone, rifampin) can increase valproate clearance, while enzyme inhibitors (e.g., felbamate) can decrease valproate clearance.

Therefore increased monitoring of valproate and concomitant drug concentrations and dosage adjustment are indicated whenever enzyme-inducing or inhibiting drugs are introduced or withdrawn (7.1)

Because of these changes in valproate clearance, monitoring of valproate and concomitant drug concentrations should be increased whenever enzyme inducing drugs are introduced or withdrawn.

Additionally, the relevance of these in vitro findings is uncertain for patients receiving maximally suppressive antiretroviral therapy.

Patients who are receiving concomitant anticonvulsant medications primarily metabolized by the liver, such as phenytoin and phenobarbital, may require periodic monitoring of plasma levels [see Drug Interactions (7.5) ] .

Phenytoin Phenobarbital ↓ anticonvulsant ↓ EFV Monitor anticonvulsant plasma levels periodically because of potential for reduction in anticonvulsant and/or EFV plasma levels.

Anticonvulsants: Carbamazepine ↓ carbamazepine The interaction between EFV and the drug was evaluated in a clinical study.

Alternative anticonvulsant treatment should be used.