Canadian Journal of Anesthesia, Vol 12, 569-586, Copyright © 1965 by Canadian Anesthesiologists' Society

Propanidid—A New Non-Barbiturate Intravenous Anaesthetic

¹ Department of Anaesthesia, University of Saskatchewan and University Hospital, Saskatoon, Saskatchewan

Experience gained from the use of Propanidid in fifty D. & C.'s would indicate that the drug is a rapid-acting induction agent. When it is also used to supplement nitrous oxide anaesthesia, undesirable side-effects such as rigidity, coughing, hiccough, phonation, and uncontrollable movement of the patient occur in a sufficiently large percentage of cases to make this an undesirable anaesthetic technique. There is no evidence that the side-effects are influenced by the timing of the premedication, but it would appear that if no oral airway is inserted, the percentage of smooth anaesthetics can be increased. While this possibility was not further explored, it would seem that many of the undesirable manifestations in this series could have been controlled by the addition to nitrous oxide of a more potent inhalation anaesthetic and/or the administration of a short-acting muscle relaxant. In the latter case however, the supplemental doses of Propanidid would not have been required in the first place, except perhaps early during maintenance to allow a smooth transition from induction. It is feared that the short effect of a single induction dose of Propanidid might have made such transition difficult. Our comparisons indicate that if rapid awakening from a short anaesthetic is desirable and anaeshesia is to be maintained with nitrous oxide and a supplement of an intravenous anaesthetic, then methohexital would be a preferable choice. Because of the anticipated difficulty of transition from induction to maintenance for longer procedures when the prolonged action of thiopental is no disadvantage, Propanidid cannot be considered superior to thiopental for induction purposes in general. One further grave disadvantage of the agent is the high incidence of postoperative nausea and emesis if it is used as it was in this series. On the other hand, the fact that Propanidid does not have to be prepared prior to administration and is stable in solution is a definite advantage, as are the relative cardiovascular stability and absence of primary respiratory depression. In the entire series, no thrombophlebitis was encountered, and no tissue irritation was seen on the two occasions when a small amount of the substance was inadvertently injected interstitially.

While on balance the experience with repeated injections of this agent has been such that its use under those circumstances cannot be recommended, experience with it in electroshock therapy was quite good. There was little difference between Propanidid and thiopental as far as the procedure was concerned, but again awakening from Propanidid was faster and there was no hang-over. This was much appreciated by the nursing staff, who could return the patients more quickly to their rooms with less supervision. The psychiatrists were more reserved in their judgment, and some of them felt that in terms of the over-all result of shock treatment there might be some advantage in the longer sleep provided by thiopental. Propanidid administered as a single injection direct into the vein did not cause any thrombophlebitis and was not characterized by any of the untoward side-effects or sequelae that had been present when it was used as a supplement to the maintenance of nitrous oxide anaesthesia. This would seem to indicate that the main value of Propanidid is as a single injection agent for very short surgical procedures. Since the acceptable dose of 5 mg./kg. Will only provide a momentarily quiet patient, it would be suitable only on rare occasions in our institution.

Note:

Presented at the Annual Meeting of the Canadian Anaesthetists' Society, Charlottetown, P.E.I., June 21–25, 1965