The incidence of postoperative nausea and vomiting: a retrospective comparison of alfentanil versus sufentanil.

Postoperative nausea and vomiting have been associated with the use of intravenous narcotics, and nitrous oxide may worsen the emetic effects of narcotics. Alfentanil and sufentanil are two synthetic derivatives of fentanyl; alfentanil has a shorter wake-up time than fentanyl, and sufentanil is equivalent to fentanyl. In order to study comparative emetic properties of these two drugs, patients in two different cities were randomly allocated to two different groups and retrospectively compared. Group I received sufentanil N2O/O2 with 0.25% isoflurane. Group II received alfentanil N2O/O2 with 0.25% isoflurane. With group I, the overall incidence of nausea was 31% and of vomiting was 6.2%. For group II, the overall rate for nausea was 38.2% and 8.8% for vomiting. Statistically, there was no significant difference in nausea or vomiting between groups.