The antiemetic effect of droperidol: is it dose dependent?

One hundred and thirty patients scheduled for ENT surgery were randomly allocated to one of the four groups: 3 to 5 minutes before anesthesia the first group (n = 19) received 5 mg of droperidol I.V., the second group (n = 30) 2.5 mg, the third group (n = 32) 0.5 mg and the fourth group (n = 49) received 2 ml of normal saline. Normal saline or droperidol were administered in a double blind manner from 2 ml coded ampules. The postanesthetic incidence of vomiting in the control group was 59% and was found to be significantly higher when compared with the droperidol treated groups (chi2 = 19.5228, P less than 0.0005). The incidence of vomiting in the groups treated with high, moderate or low dose of droperidol varied between 16 and 21% and did not differ significantly between them (chi2 = 0.26035, P greater than 0.80).