Overdosage with pentobarbital and secobarbital: assessment of factors related to outcome.

Factors related to clinical outcome following acute overdosage with pentobarbital or secobarbital were assessed in a series of 162 patients hospitalized during the period 1962 to 1975. The mean ingested dose was 2 Gm (range 0.2 to 10.0 Gm), and plasma barbiturate concentrations ranged from 2.0 to 72.0 microgram/ml. Serious intoxication was common. Intubation and assisted ventilation were required in 59 per cent of patients, and 23 per cent developed clinically important hypotension. Four patients died, all relatively young females. Multiple regression and discriminant function analyses, performed on a subset of 88 patients for whom complete data were available, indicated that plasma barbiturate concentration and/or ingested dose were the most important correlates of serious intoxication among identifiable variables available on admission. Coingestion of other central nervous system depressants, such as ethanol, had no obvious effect on outcome. The present study suggests that measurement of plasma barbiturate concentrations is of value in identifying patients at risk of developing serious intoxication after overdosage with pentobarbital or secobarbital.