Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.
Anzemet (Hoechst Marion Roussel)
50 mg and 200 mg tablets
20 mg/mL in 0.625 mL and 5 mL ampoules
Indication: prevention of nausea and vomiting
Vomiting is often a problem during chemotherapy for cancer, especially if highly emetogenic drugs such as cisplatin are used. There are several approaches to dealing with this problem including the use of 5HT3 receptor blockers. Dolasetron is a new drug in this class which already contains ondansetron and tropisetron. In addition to patients having chemotherapy, dolasetron can also be used in the management of postoperative nausea and vomiting. It is not approved for use in children.
Dolasetron is given once a day. Patients can receive the injection 30 minutes before, or take a tablet one hour before, chemotherapy. The tablet is well absorbed and, like injectable dolasetron, is rapidly converted to an active metabolite. This metabolite has a half-life of 7-9 hours with 30% being excreted in the urine and the rest by further metabolism. Although clearance is reduced by hepatic or renal impairment, no dose adjustments are advised.
Most patients will benefit from having a 5HT3 receptor blocker before chemotherapy. Dolasetron is probably as effective as the other drugs and, similarly, the addition of a corticosteroid will enhance its efficacy. To reduce delayed nausea and vomiting, dolasetron can be continued for up to 7 days.
Adverse effects which have been reported in patients taking dolasetron include headache, dizziness and diarrhoea. Arrhythmias have been reported, but their association with dolasetron is unclear.