Aprepitant: drug-drug interactions in perspective

The implications of chemotherapeutic drug-drug interactions can be serious and thus need to be addressed. This review concerns the potential interactions of the antiemetic aprepitant, a neurokinin-1 receptor antagonist indicated for use (in Europe) in highly emetogenic chemotherapy and moderately emetogenic chemotherapy (MEC) in combination with a 5-hydroxytryptamine-3 (5-HT3) receptor antagonist and corticosteroids and (in the United States) in combination with other antiemetic agents, for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy including high-dose cisplatin. When considering use of aprepitant for prevention of chemotherapy-induced nausea and vomiting, its potential drug-drug interaction profile as a moderate inhibitor of cytochrome P-450 isoenzyme 3A4 (CYP3A4) has been a source of concern for some physicians and other health care professionals. We explore in this paper how real those concerns are. Our conclusion is that either no interaction or no clinically relevant interaction exists with chemotherapeutic agents (intravenous cyclophosphamide, docetaxel, intravenous vinorelbine) or 5-HT3 antagonists (granisetron, ondansetron, palonosetron). For relevant interactions, appropriate measures, such as corticosteroid dose modifications and extended International Normalized Ratio monitoring of patients on warfarin therapy, can be taken to effectively manage them. Therefore, the concern of negative interactions remains largely theoretical but needs to be verified with new agents extensively metabolized through the 3A4 pathway.