A clinical trial of alfentanil as an adjuvant for short anaesthetic procedures.

Alfentanil 700 micrograms and fentanyl 100 micrograms were compared as anaesthetic adjuvants in 90 patients undergoing short duration gynaecological procedures. The results show that, at the chosen dose ratio, alfentanil causes a higher frequency of post-induction apnoea, but thereafter the respiratory effects of the two drugs were comparable. No differences in incremental requirements or evoked movements were found. Among patients who had been given ergometrine, the alfentanil group suffered a greater frequency of nausea and vomiting in the period immediately after operation. It is concluded that in single i.v. doses, alfentanil 700 micrograms is more potent than fentanyl 100 micrograms. Moreover, the results suggest that, unlike fentanyl, this very short acting agent would be used to greater effect if given in divided doses during surgery.