Antiemetic

For evaluation of the antiemetic effects of the drugs animal models (Ferret,cat dog etc) are used. Although good guidelines may be established through the animal experiments, they may not give accurate indication of the antiemetic effect of the antiemetic drugs in patients due to species differences in pharmacokinetic and pharmacodynamic responses. Therefore, Ipecacuanha-induced emesis and flare models are used to predict more accurately the antiemetic effect of the antiemetic drugs. In ipecacuanha-induced emesis model in 10 healthy human volunteers slow intravenous injection of ondanserton -2 ml. (4 mg) was given over 5 minutes.Thirty minutes after inj. ondanserton, 30 ml. oral syrup of tincture ipecac was given with glassful of water. Then the parameters like time, number and duration of emesis were noted over 6 hour’s period. In flare model in 6 healthy human volunteers Injection Serotonin 0.05 ml of 12.98 µM was given intradermally on the flexor aspect of forearm. Resulting flare response was measured over 5 minutes. At the end of half an hour, injection ondansetron and same dose of injection serotonin was given intradermally. Resulting flare response was measured in the similar way. Out of these two models, ipecac model is technically easy and clinically relevant but its tolerability is less. Flare model has excellent tolerability but it is technically not very easy. Thus one can choose the effective model accordingly. Key words: Antiemetic, Ipecacuanha, Ondansetron, Serotonin