Insufficient Effectiveness of 5-Hydroxytryptamine-3 Receptor Antagonists Due to Oral Morphine Administration in Patients With Cisplatin-Induced Emesis

Abstract

PURPOSE: To compare the effect of 5-hydroxytryptamine-3 (5HT3) receptor antagonists in cancer patients receiving chemotherapy including cisplatin (CDDP), with or without sustained-release oral morphine (MS Contin; Shionogi Co, Osaka, Japan). PATIENTS AND METHODS: We retrospectively studied 58 lung cancer patients given chemotherapy including at least 50 mg/m2 CDDP with 5-HT3 receptor antagonists between January 1996 and December 1997. Number of vomiting episodes, average porportions of hospital-supplied meals consumed (0 to 100%, as an index of appetite), and nausea severity scores (0 to 2 points, subjective patient judgment) were compared between oral morphine–administered (+) and morphine-free (−) groups. RESULTS: Sixteen morphine(+) and 42 morphine(−) cases were used. In cases of acute emesis (within 24 hours after CDDP injection), morphine(+) and morphine(−) groups were significantly different in number of vomiting episodes (1.25 and 0.14, respectively; P < .0001), appetite (58.13% and 90.24%; P < .0001), and nausea severity scores (1.63 and 0.62; P < .0001). In delayed-emesis cases (24 to 120 hours after CDDP), these groups differed significantly in number of vomiting episodes (1.94 and 0.43, respectively; P = .0001), appetite (23.13% and 52.08%; P < .0001), and nausea severity (1.38 and 0.91; P = .009). There were no significant differences in sex, age, anticancer drugs concurrent with CDDP, CDDP dose, corticosteroid administration, clinical stage, or type of 5-HT3 antagonist. CONCLUSIONS: These data suggest that morphine can markedly reduce the effectiveness of 5-HT3 receptor antagonists in patients receiving chemotherapy that includes CDDP. These results require confirmation by reinvestigation of clinical data on the efficacy of 5-HT3 receptor antagonists and by extensive prospective analyses.