Abstract
The antiemetic effectiveness of 5-HT3 receptor antagonists in combination with dexamethasone in patients receiving short-term infusion chemotherapy has been well demonstrated. Less information is available about the efficacy of the same antiemetic combination in patients treated with regimens of chemotherapy in which the drugs are delivered in continuous infusion of several hours. The purpose of this study was to report the effectiveness of a double administration of antiemetic drugs in patients treated with strong emesis-inducing drugs for several days. In this study, 19 male and 13 female patients with osteosarcoma, ages 9 to 45 years, treated with chemotherapy, received intravenous tropisetron 5 mg plus dexamethasone 8 mg every 12 hours during the first two cycles of the preoperative treatment: cisplatin 120 mg/m2 over 48 hours followed by Adriamycin 75 mg/m2 delivered in 24 hours and continuous infusion of ifosfamide 15 g/m2 over 120 hours. The assessment of the antiemetic efficacy was performed three times every day: from 8:00 am to 4:00 pm, from 4:00 pm to 12:00 am, and from 12:00 am to 8:00 am. The patients were followed from the beginning of the treatment until 2 hours after its end, when they were discharged from hospital. Complete protection from emesis was obtained in 80% of the 256 days of treatment: 81% during the first cycle (cisplatin 120 mg/m2 in 48 hours followed by Adriamycin 75 mg/m2 delivered in 24 hours) and 79% during the second cycle (continuous infusion of ifosfamide 15 g/m2 in 120 hours). In both cycles, complete protection declined from the first to the last day of treatment (from 100% to 62% during the first cycle and from 100% to 63% during the second cycle). These results indicate that when chemotherapy is administered in a protracted infusion, higher doses of antiemetic agents are necessary to achieve acceptable antiemetic activity.