Rabeprazole intake does not affect systemic exposure to capecitabine and its metabolites, 5′-deoxy-5-fluorocytidine, 5′-deoxy-5-fluorouridine, and 5-fluorouracil

Purpose Several retrospective studies have shown that the antitumor efficacy of capecitabine-containing chemotherapy decreases when co-administered with a proton pump inhibitor (PPI). Although a reduction in capecitabine absorption by PPIs was proposed as the underlying mechanism, the effects of PPIs on capecitabine pharmacokinetics remain unclear. We prospectively examined the effects of rabeprazole on the pharmacokinetics of capecitabine and its metabolites.