Comparación de los efectos profilácticos del droperidol y del ondansetrón sobre el prurito provocado por la morfina subaracnoidea

Background and objectives

The prophylactic effect of ondansetron on subarachnoid morphine-induced pruritus is controversial, while evidence suggests that droperidol prevents pruritus. The aim of this study is to compare the effects of droperidol and ondansetron on subarachnoid morphine-induced pruritus.

Methods

One hundred eighty patients ASA I or II patients scheduled to undergo cesarean sections under subarachnoid anesthesia combined with morphine 0.2 mg were randomized to receive, after the child's birth, metoclopramide 10 mg (Group I-control), droperidol 2.5 mg (Group II) or ondansetron 8 mg (Group III). Postoperatively, the patients were assessed for pruritus (absent, mild, moderate or severe) or other side effects by blinded investigators. Patients were also blinded to their group allocation. The tendency to present more severe forms of pruritus was compared between groups. NNT was also determined.

Results

Patients assigned to receive droperidol (proportional odds ratio: 0.45 [95% confidence interval 0.23-0.88]) reported less pruritus than those who received metoclopramide. Ondansetron effect was similar to metoclopramide (proportional odds ratio: 0.95 [95% confidence interval 0.49-1.83]). The NNT for droperidol and ondansetron was 4.0 and 14.7, respectively.

Conclusions

Ondansetron does not inhibit subarachnoid morphine-induced pruritus.