The comparative potencies of buthalitone and thiopentone in out-patient anaesthesia.

THIOPENTONE was introduced to clinical anaesthesia by Lundy in 1934 and the first reports of its use appeared in the following year (Lundy, 1935; Lundy and Tovell, 1935). Since then, thiopentone has almost entirely superseded other intravenous agents and has become the standard agent for inducing anaesthesia. It is not, however, without certain dangers. The main disadvantages are the occasional occurrence of laryngeal spasm (Lee, 1953; Dundee, 1956) and the ease with which respiratory depression due to overdosage can be produced. Another objection to thiopentone is that, following induction and a brief period of anaesthesia, the patients often have a relatively prolonged period when they are drowsy and confused and in a state described by Lundy (1935) as resembling alcoholic inebriation. Research workers have been constantly seeking other similar drugs which.would show a shorter recovery period with less postanaesthetic confusion, and buthalitone was introduced as such a drug. Claims have also been made that the incidence of respiratory depression and vagotonic effects is less with this drug than with thiopentone (Davidson and Love, 1956). Buthalitone was first prepared by Miller et al. (1936) but it was not used clinically until 1954 when Weese and Koss reported on a clinical trial of 350 cases. This has been followed by numerous reports of other clinical trials in which this drug has been used (Dietmann, 1954; Pestel, 1954; Vollmer and Haaf, 1954; Ritter and Schaffer, 1954; Bergentz and Arosenius, 1955; De Cesare and Paoletti, 1955; Nobes, 1955a, b; Ruddell, 1955; Westerborn and Stenberg, 1955; Guldmann, 1956; Manni et al., 1956; Rajagopalan, 1956; Williams, 1956; Young, 1956; Duffield and Ginsberg, 1957; Mostert and Durham, 1957). Following our investigation into the use of buthalitone sodium in out-patient anaesthesia (1957), it seemed to us to be reasonable to try usiir^ thiopentone under similar conditions and to see whether the claims for buthalitone could be substantiated and to make a comparison between the two drugs. Both buthalitone and thiopentone are thiobarbiturates, the former being sodium 5-allyl5-isobutyl-2-thiobarbiturate having the formula: