Interactions between iressa(gefitinib) and Aciphex (rabeprazole)
rabeprazole and gefitinib (Moderate Drug-Drug)
MONITOR: Coadministration with drugs that cause significant, sustained elevations in gastric pH such as H2-receptor antagonists and proton pump inhibitors may decrease the plasma concentrations of gefitinib. The exact mechanism of interaction is unknown. According to the manufacturer, coadministration with high dosages of ranitidine and sodium bicarbonate (to maintain the gastric pH above 5.0) reduced the mean area under the plasma concentration-time curve of gefitinib by 44% in healthy male volunteers.
MANAGEMENT: The possibility of a diminished therapeutic response to gefitinib should be considered during coadministration with H2-receptor antagonists or proton pump inhibitors. Pharmacologic response to gefitinib should be monitored more closely whenever one of these agents is added to or withdrawn from therapy.
