A Double‐Blind, Placebo‐Controlled, Dose‐Ranging Safety Evaluation of Single‐Dose Intravenous Dolasetron in Healthy Male Volunteers

The safety and tolerability of dolasetron mesylate, a potent and selective 5-HT3 receptor antagonist, were evaluated after single intravenous doses in healthy male volunteers. In this double-blind, placebo-controlled, randomized, phase I study, 80 subjects received either placebo or dolasetron in escalating doses (0.6 to 5.0 mg/k). Subjects were monitored for adverse events, vital sign and laboratory alterations, and changes in electrocardiographic (ECG) intervals and electroencephalographic (EEG) patterns. Overall, the percentage of subjects reporting adverse events was similar in those receiving dolasetron (44/64; 68.8%) or placebo (10/16; 62.5%); most adverse events were mild in severity. Subjects receiving dolasetron reported a higher incidence of central nervous system (headache and dizziness/lightheadedness), gastrointestinal (increased appetite and nausea), and visual adverse events and taste alterations. No clinically significant changes in laboratory variables were observed. Transient and asymptomatic ECG changes (small mean increases in PR interval and QRS complex duration versus baseline) were noted in several subjects at 1 to 2 hours after infusion at doses > or = 3.0 mg/kg. Transient, mild blood pressure decreases were observed in five subjects, including one on placebo. Dolastron mesylate was well tolerated in single intravenous doses up to 5.0 mg/kg in healthy male volunteers. Clinical studies of the drug are ongoing for antiemetic indications.