Alfentanyl (R39209): initial clinical experience with a new narcotic analgesic.

R39209 (Alfentanyl), a new narcotic analgesic with a uniquely short duration of effect, was used to supplement nitrous oxide and oxygen for the maintenance of anaesthesia. Twenty-two patients undergoing minor surgery were studied. Clinical anaesthesia was excellent or good in most (16) of the patients, and recovery was excellent or good in 18 patients, waking time being less than one minute in 15 patients. However the incidence of complications and side-effects, mainly movement, apnoea, difficulty in assisting ventilation, nausea and vomiting was high. Intravenous administration of R39209 during anaesthesia induced significant depression of respiratory rate and minute volume during the second, third and fourth minutes after injection. There was an unexplained significant rise in respiratory rate and minute volume in the first 30 seconds after the first injection. The first administration of R39209 also caused an unexplained, significant reduction in cardiac rate. An insignificant rise in mean systolic blood pressure followed injection of the drug. The transient effect of R39209 was confirmed in clinical practice, and the drug exhibited the features of a typical narcotic analgesic. It is concluded that R39209 will have a useful place in anaesthetic practice, and that better clinical results will be obtained with more experience of the drug, and better selection of indications for its use.