Pattern of carboplatin-induced emesis

In contrast to the broad experience concerning the therapeutic use of carboplatin, only limited data are available regarding the patterns of carboplatin-induced emesis, one of its most distressing side effects. This study reports frequency, severity and time course of carboplatin-induced vomiting and nausea refractory to 5-HT3 antagonism. A total of 216 patients receiving single-day carboplatin-based chemotherapy regimen were enrolled into an open multicenter study focusing on the safety and efficacy of ondansetron 8 mg t.d.s. Emesis on day 1 occurred in 22% and nausea in 75% of the patients; 44% of patients reported some degree of vomiting within the 5 days observation period. The risk for emesis and nausea over 2-5 days was increased in patients suffering from emesis on day 1 (relative risk 2.25 for vomiting and 2.84 for nausea, respectively). The median cumulative number of emetic episodes was 0 for all patients and 4 for the patients who did vomit at least on 1 day. Vomiting began on average 1.77 days following chemotherapy administration. The mean duration of vomiting was 2 days and 3.1 days for nausea. Carboplatin showed a monophasic prolonged pattern of emesis. The combination with cyclophosphamide led to an earlier onset and a higher frequency of vomiting. The analysis of the pattern of emesis refractory to 5-HT3 receptor blockade should help to describe the course of emesis, which is probably triggered through a 5-HT3 receptor-independent mechanisms.