Interactions between rabeprazole and Fosamprenavir (fosamprenavir)
rabeprazole and fosamprenavir (Moderate Drug-Drug)
MONITOR: Coadministration with H2-receptor antagonists or proton pump inhibitors may decrease the oral bioavailability of amprenavir from its prodrug, fosamprenavir. In 30 study subjects, ranitidine (300 mg single oral dose) decreased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amprenavir from fosamprenavir (1400 mg single oral dose) by 51% and 30%, respectively, compared to administration of fosamprenavir alone. The mechanism of interaction has not been described. It is possible that fosamprenavir solubility decreases with increasing pH, thus inhibition of gastric acid secretion may interfere with dissolution of the drug. Subtherapeutic antiretroviral drug levels may lead to reduced viral susceptibility and development of resistance.
MANAGEMENT: Caution is advised if fosamprenavir is prescribed with H2-receptor antagonists or proton pump inhibitors. Antiretroviral response should be monitored closely during coadministration.
