Ipecacuanha‐induced emesis: A human model for testing antiemetic drug activity

In a double‐blind, randomized, parallel‐group study, five groups of 10 healthy men received single 5‐minute infusions of 8 mg, 4 mg, 1 mg, 0.25 mg, or 0.1 mg ondansetron (as hydrochloride dihydrate) 30 minutes before oral administration of 30 ml syrup of ipecacuanha. Emetic episodes and nausea (100 mm visual analog scale) were assessed over an 8‐hour period. There were no emetic episodes after 8 or 4 mg ondansetron. Seven, nine, and 10 subjects vomited after 1 mg, 0.25 mg and 0.1 mg ondansetron, respectively, with median times to onset of 62, 31, and 37 minutes. Median peak nausea scores were 0 mm for both 8 and 4 mg ondansetron and 30, 53, and 26 mm for 1, 0.25, and 0.1 mg ondansetron. Adverse events were mild. This model showed a close correlation with clinically effective doses of ondansetron. It may be successfully and safely used to assess the antiemetic potential of 5‐HT 3 ‐receptor antagonists in healthy subjects. Clinical Pharmacology and Therapeutics (1993) 54, 53–57; doi: 10.1038/clpt.1993.109