ANTIEMETIC SELECTION

ANTIEMETIC SELECTION Chemotherapy-induced nausea and vomiting (CINV) is one of the most notorious and debilitating adverse drug effects experi- enced by patients treated with cytotoxic chemotherapy agents [9]. Ineffective control of CINV can lead to patient distress, unacceptable QOL, and treatment noncompliance [10]. Since their advent, serotonin receptor antagonists (5HT3-RA) have been the backbone of CINV prophylaxis and treatment. CYP2D6 is a key metabolic pathway for inactivation of most 5HT3-RAs— particularly ondansetron and palonosetron, the two most widely used 5HT3-RAs. For example, CYP2D6 UMs, who are found in approximately 5% of the white population, degrade ondansetron too rapidly, resulting in ineffective blood levels and thus weak control of CINV [10–13]. Studies showmore epi- sodes of vomiting and higher reported nausea for CYP2D6 UMs receiving ondansetron on equivalent chemotherapy regimens [13, 14].