Nausea and vomiting are common side effects of most cytotoxic agents, cisplatin being the most emetogenic. All patients given high doses of cisplatin will vomit it the 24 hours following its administration unless antiemetics are given. However,
none of
the currently available antiemetics are entirely effective. Ondansetron, one of a new class of antiemetic agents which act by selective 5-HT receptor blockade, has been shown to be more effective than high-dose metoclopramide in controlling
cisplatin
induced emesis. Complete or major control of emesis has been achieved in 65~75% of patients. The efficacy achieved with ondansetron as a single agent is there fore a significant therapeutic advance; however, Control is suboptimal in approximately
25~35%
of patients and further improvements are desirable.
In an attempt to further improve efficacy in this group of patients, a prospective randomised study was carried out comparing metoclopramide, ondansetron alone with ondansetron plus dexamethasone. Ondansetron at a dose of 8 mg was given as a slow
intravenous injection prior to the administration of displatin, and then given as two further 8 mg doses 4 and 8 hours after the start of first dose. During day 2~5, ondansetron was given orall by 8 mg q8 hours daily, Dexamethasone as a single
intravenous dose of 20 mg prior to cisplatin was given in the combination therapy of ondansetron.
Complete of major control of acute emesis was achieved in 95% of patients receiving the cmbination of ondansetron plus dexamethasone and in 60% of patients receiving ondansetron alone (p<0.05). None or mild nasuea during 24 hours following
anti-emetic
therapy was observed in 70% of patients receiving the combination and in 55% in patients receiving ondansetron alone(p>0.05). Ondansetron treatment was well tolerated. The addition of a single dose of dexamethasone to ondansetron significantly
improves
the control of emesis and nausea compared to ondansetron monotherapy in patients receiving highdose cisplatin.
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