Carcinogenesis, Mutagenesis, Impairment of Fertility
In a 24-month carcinogenicity study, there was a statistically significant (P<0.001) increase in the incidence of combined hepatocellular adenomas and carcinomas in male mice treated with 150 mg/kg/day and above. In this study, mice (CD-1) were treated orally with dolasetron mesylate 75, 150, or 300 mg/kg/day (225, 450 or 900 mg/m2/day). For a 50 kg person of average height (1.46 m2body surface area), these doses represent 3, 6, and 12 times the recommended clinical dose (74 mg/m2) on a body surface area basis. No increase in liver tumors was observed at a dose of 75 mg/kg/day in male mice and at doses up to 300 mg/kg/day in female mice.
In a 24-month rat (Sprague-Dawley) carcinogenicity study, oral dolasetron mesylate was not tumorigenic at doses up to 150 mg/kg/day (900 mg/m2/day, 12 times the recommended human dose based on body surface area) in male rats and 300 mg/kg/day (1800 mg/m2/day, 24 times the recommended human dose based on body surface area) in female rats.
Dolasetron mesylate was not genotoxic in the Ames test, the rat lymphocyte chromosomal aberration test, the Chinese hamster ovary (CHO) cell (HGPRT) forward mutation test, the rat hepatocyte unscheduled DNA synthesis (UDS) test or the mouse micronucleus test.
Dolasetron mesylate was found to have no effect on fertility and reproductive performance at oral doses up to 100 mg/kg/day (600 mg/m2/day, 8 times the recommended human dose based on body surface area) in female rats and up to 400 mg/kg/day (2400 mg/m2/day, 32 times the recommended human dose based on body surface area) in male rats.
Pregnancy Category B
Teratology studies have not revealed evidence of impaired fertility or harm to the fetus due to dolasetron mesylate. These studies have been performed in pregnant rats at oral doses up to 100 mg/kg/day (8 times the recommended human dose based on body surface area) and pregnant rabbits at oral doses up to 100 mg/kg/day (16 times the recommended human dose based on body surface area). There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
A 59-year-old man with metastatic melanoma and no known pre-existing cardiac conditions developed severe hypotension and dizziness 40 minutes after receiving a 15 minute intravenous infusion of 1000 mg (13 mg/kg) of dolasetron mesylate. Treatment for the overdose consisted of infusion of 500 mL of a plasma expander, dopamine, and atropine. The patient had normal sinus rhythm and prolongation of PR, QRS and QTc intervals on an ECG recorded 2 hours after the infusion. The patient's blood pressure was normal 3 hours after the event and the ECG intervals returned to baseline on follow-up. The patient was released from the hospital 6 hours after the event.
Following a suspected overdose of ANZEMET Injection, a patient found to have second-degree or higher AV conduction block with ECG should undergo cardiac telemetry monitoring.
There is no known specific antidote for dolasetron mesylate, and patients with suspected overdose should be managed with supportive therapy. Individual doses as large as 5 mg/kg intravenously or 400 mg orally have been safely given to healthy volunteers or cancer patients.
It is not known if dolasetron mesylate is removed by hemodialysis or peritoneal dialysis.
A 7-year-old boy received 6 mg/kg of dolasetron mesylate orally before surgery. No symptoms occurred and no treatment was required.
Single intravenous doses of dolasetron mesylate at 160 mg/kg in male mice and 140 mg/kg in female mice and rats of both sexes (6.3 to 12.6 times the recommended human dose based on body surface area) were lethal. Symptoms of acute toxicity were tremors, depression and convulsions.