Twenty-one RCTs (n=3,091) were included.
The median quality score was 3 points (range: 1 to 4).
Prevention of PONV (4 RCTs).
Haloperidol 0.5 to 4 mg reduced PONV in the first 24 hours compared with placebo; the RB was 1.26 to 1.51 and the NNT 3.2 to 5.1 (based on 1 RCT, n=502). There was no evidence of dose responsiveness. Compared with placebo, haloperidol 0.25 mg was not anti-emetic for nausea (RB 1.19, 95% CI: 0.95, 1.50) or vomiting (RB 1.05, 95% CI: 0.85, 1.29), based on 1 RCT (n=101).
Treatment of established PONV at 2 to 4 hours (6 RCTs and 5 unpublished trials).
Intramuscular haloperidol 1 mg showed an RB of 1.53 (95% CI: 1.17, 2.00; NNT 6) compared with placebo ; no statistical heterogeneity was found (P=0.06). Haloperidol 2 mg showed an RB of 1.73 (95% CI: 1.11, 2.68; NNT 4) compared with placebo.
Nausea and vomiting related to GI diseases (5 RCTs and 3 unpublished trials).
Intramuscular haloperidol (1 and 2 mg) was shown to be efficacious for the treatment of nausea and vomiting across several observation periods (0 to 12 hours). The cumulative incidence of vomiting over 12 hours suggested greater efficacy of the 2-mg dose, although this was based on an indirect comparison. The RBs and 95% CI were presented in the paper.
Chemotherapy (5 RCTs) and radiation therapy (1 RCT). Studies compared haloperidol with a variety of comparators, but no comparison was examined in more than one study.
Extrapyramidal symptoms: 2 trials found a combined rate of 0.1% (1 of 806 exposed patients) for extrapyramidal symptoms with 4 mg haloperidol.
Sedation and drowsiness: of the 2 studies, one demonstrated a significant effect in favour of intravenous haloperidol 5 mg (RR 2.09, 95% CI: 1.73, 2.52), while the other found no statistical difference between intravenous haloperidol 1 mg and the control.
Arterial hypotension: a small but non significant increase in arterial hypotension was shown in patients given 1 to 4 mg haloperidol, compared with the control (odds ratio 1.05, 95% CI: 0.49, 2.22).
Other adverse effects: there was no significant difference between haloperidol and placebo for arterial hypertension, blurred vision, chills and shivering, bradycardia, tachycardia and nystagmus. No cases of cardiac arrhythmia were reported with haloperidol.