Trimethobenzamide is a dopamine D2 receptor antagonist and antiemetic.1 It prevents emesis induced by the dopamine agonist apomorphine in dogs when used at a dose of 20 mg/kg and stimulates contraction of isolated guinea pig ileum (ED50 = 8.7 μg/mL).2 Trimethobenzamide (20 mg/kg) decreases apomorphine-induced pecking responses in pigeons by 20% and increases the latent period of pecking from 4.3 to 8 minutes.3 Trimethobenzamide (6.7 g/kg per day for 2 weeks) enhances compensation and decreases recovery time from 70 to 32 weeks in unilaterally labyrinthectomized cats, a model of vestibular injury.4 Formulations containing trimethobenzamide have been used to treat nausea and vomiting.
1.Smith, H.S., Cox, L.R., and Smith, B.R.Dopamine receptor antagonistsAnn. Palliat. Med.1(2)137-142(2012) 2.Shallek, W., Heise, G.A., Keith, E.F., et al.Anti-emetic activity of 4-(2-dimethylaminoethoxy)-N-(3,4,5-trimethoxybenzoyl) benzylamine hydrochlorideJ. Pharmacol. Exp. Ther.126(3)270-277(1959) 3.Dhawan, B.N., Saxena, P.N., and Gupta, G.P.Antagonism of apomorphine-induced pecking in pigeonsBr. J. Pharmacol. Chemother.16(2)137-145(1961) 4.Peppard, S.B.Effect of drug therapy on compensation from vestibular injuryLaryngoscope96(8)878-898(1986)