Trimethobenzamide (trade names Tebamide, Tigan) is an antiemetic used to prevent nausea and vomiting. Trimethobenzamide is an antagonist of the D2 receptor, that affects the chemoreceptor trigger zone (CTZ) of the medulla oblongata to suppress nausea and vomiting. The oral bioavailability of trimethobenzamide is 60% to 100%. The time to peak is about 45 minutes after oral administration and; I.M. about 30 minutes after intramuscular administration. The onset action of trimethobenzamide for antiemetic effects is 10-40 minutes after oral administration and; 15-35 minutes after intramuscular administration. The duration of action is 3-4 hours. Trimethobenzamide is generally considered the most potent antiemetic that does not have effects on the serotonergic, dopaminergic, or histaminergic systems, so it has a lower likelihood of causing undesired side effects. Possible side effects include drowsiness, dizziness, headache, diarrhea, muscle cramps, and blurred vision. More serious adverse effects include skin rash, tremors, parkinsonism, and jaundice.