Antiemetic effect of haloperidol in the dog as related to plasma level and dose.

A positive and highly significant correlation was found between SC dose, plasma concentration, and antiemetic effect of haloperidol in the dog. To protect dogs from apomorphine-induced emesis, a concentration of 1 ng haloperidol/ml plasma was always sufficient, whereas protection from emesis was never obtained with plasma levels lower than 0.53 ng/ml. The elimination rate of haloperidol from plasma varied from 1.53 to 2.60 among different animals. Thus, the interindividual variability to haloperidol was surprisingly low. Antiemetic effect and plasma elimination of haloperidol were not related to body weight.