EFFECTS OF PROPOFOL ON IPECACUANHA-INDUCED NAUSEA AND VOMITING

Background: The purpose of this study was to evaluate if propofol has 5-HT3 antagonistic effects. Ipecacuanha is known to release serotonin (5-HT) in the gastrointestinal tract and therefore ipecacuanha syrup w as used to induce nausea and vomiting. The 5-HT3 antagonist ondansetro n was used as a control substance. Method: Ten healthy male volunteers (20-37 years) were studied on three occasions and were randomly alloc ated to receive a concomitant infusion of propofol (initial bolus 0.1 mg kg(-1) then 1 mg kg(-1)h(-1)), ondansetron (initial bolus 0.11 mg k g(-1) then 14 mu g kg(-1)h(-1)) and placebo on either occasion. The in fusions started 30 min before oral ingestion of 30 ml of ipecacuanha a nd continued until 150 min after the intake. The number of retchings w as recorded and the intensity of nausea was estimated by the subjects on a visual analog scale. Results: During the first 150 min after inge stion of ipecacuanha there were no retchings during the ondansetron in fusion (P=0.01 vs placebo, P=0.02 vs propofol) and significantly fewer retchings during propofol infusion compared to placebo (P<0.02). Ther e was no nausea during the ondansetron infusion (P<0.01 vs placebo and propofol) but the volunteers experienced nausea both during the place bo and propofol infusion gus). Conclusion: This study in volunteers ha s shown that propofol reduces the intensity of retching after oral int ake of ipecacuanha syrup. As ipecacuanha releases 5-hydroxytryptamine, it can be concluded that propofol may have a weak 5-HT3 antagonistic effect.