Drug Interaction Report

MONITOR: Coadministration with fenofibrate may increase the plasma concentrations and risk of adverse effects of drugs that are substrates of CYP450 2C19, 2A6, and 2C9 isoenzymes. The proposed mechanism, based on in vitro data, is decreased clearance due to fenofibrate-mediated inhibition of CYP450 2C19, 2A6, and 2C9.

MANAGEMENT: Until more information is available, caution is advised if fenofibrate is used concomitantly with drugs that are substrates of CYP450 2C19, 2A6, or 2C9 isoenzymes, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring should be considered whenever fenofibrate is added to or withdrawn from therapy with these drugs. Patients should be monitored for the development of adverse effects.

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.