Canadian Journal of Anesthesia, Vol 6, 108-118, Copyright © 1959 by Canadian Anesthesiologists' Society

A Clinical Comparison of Sodium Thiopental (Pentothal®), Sodium Methitural (Neraval®), Sodium Buthalitone (Transithal®), and Sodium Hexobarbital (Evipal®)

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

The claim that some of the newer barbiturates have a shorter duration than older agents has not been borne out by the present investigation in regard to thiopental, but is true in regard to sodium hexobarbital. If sodium thiopental, sodium buthalitone, or sodium methitural is used as the sole agent for a standard operative procedure, the least amount which will keep the patient quiet on the table being administered, there is no difference in the total sleep time or in the waking time from the last injection.

If dose per minute of anaesthesia for such a standard procedure is taken as an indication, the relative potency of the four agents studied is: thiopental, 1; methitural, 0.5; hexobarbital, 0.4; and buthalitone, 0.35. The most potent agent shows the highest incidence of apnoea following induction and the longest mean duration of apnoea; the less potent ones have a lower incidence and a shorter mean duration of apnoea.

The incidence of cough during induction and maintenance is very much greater with methitural than with the other three drugs, whereas the incidence of hiccough during maintenance is much greater with buthalitone than with the other three drugs. The incidence of moderate and gross movements following sodium hexobarbital is very high indeed. Sodium thiopental appears the most predictable and reliable of the four drugs, and it is invariably possible to control slight movements of patients and thus maintain smooth anaesthesia. With the other three drugs this is not always possible, and with sodium hexobarbital it is rarely possible, even when the amount of drug administered is markedly increased. Sodium methitural and sodium hexobarbital are the only ones which seem to relax abdominal muscles slightly. This action reduces the need for relaxants for bimanual pelvic examination considerably compared with the other two drugs.

In the post-anaesthetic period hiccough is again a relatively frequent phenomenon after methitural anaesthesia and nausea and vomiting are very common following hexobarbital. After buthalitone and hexobarbital dizziness and headache are more frequently seen than after the other two agents.

In summary, it appears that sufficiently large doses of the inherently shorteracting methitural and buthalitone are required for smooth anaesthesia, so that total sleep time is in the end no different from thiopental. Anaesthesia is neither as smooth nor as predictable and free from annoying minor side effects as it is when thiopental is used. These disadvantages outweigh the shorter post-induction apnoea with methitural and buthalitone. The very high incidence of movements during anaesthesia, the long postoperative sleep and the high incidence of nausea and emesis in the post-anaesthetic period far outweigh the low incidence and duration of post-induction apnoea following sodium hexobarbital anaesthesia.

Note:

Supplies of sodium methitural, sodium buthalitone, and sodium hexobarbital were made available through the courtesy of the Schering Corporation, Montreal, P.Q., Poulenc Ltd., Montreal, P.Q., and Winthrop Laboratories of Canada Ltd., Windsor, Ont., respectively.