Treatment of chemotherapy-induced nausea and vomiting with 5-hydroxytryptamine type 3 receptor antagonists

5-hydroxytryptamine 3 (5-HT3) receptor antagonists have proved to be highly efficacious in the prevention and treatment of chemotherapy-induced nausea and vomiting (CINV). However, several questions remain concerning the relative efficacy of various approved anti-emetics, especially with respect to dosage, duration and timing of administration, as well as differences in toxicity profiles. Thus it seemed appropriate to assess the current therapeutic results in routine daily practice, when applying antiemetic therapy according to established guidelines. Within LINO e.V., a group of medical oncologists in private ambulant practice (LINO: Association of private-practice medical oncologists in Bavaria), a total of 738 cycles of moderately or highly emesis-inducing chemotherapy were randomly assigned to three treatment options: (1)granisetron 1 mg (GRA1). (2) 3 mg (GRA3), and (3) ondansetron 8 mg (OND8), each combined with 8 mg dexamethasone. Incidence and severity of acute (day 1) and delayed CINV (day 2-5) and the subjective assessment of efficacy were documented on questionnaires filled in by the patients. All of the three regimens adequately prevented vomiting in the majority of the patients. However, all measured effects showed an uniform trend towards slightly decreased efficacy with 8 mg of ondansetron. These differences were predominantly detected with respect to delayed CINV on days 2 to 5, especially after chemotherapy with anthracyclin/cyclophosphamide combination therapy. Granisetron, at two different dosage regimens, and ondasetron showed adequate reduction in chemotherapy-induced nausea and vomiting, but ondansetron worked slightly less so.