Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations

Barbiturates and alcohol are frequently found in combination in cases of accidental or intentional fatal self-poisoning. Unfortunately, the lack of any precise knowledge concerning their interaction creates difficult problems when an interpretation of toxicological data is sought. 1 In the following work the joint action of single barbiturates and alcohol is examined and a means of quantifying it is presented. 2 The effects of different amounts of alcohol on fatal amylobarbitone, butobarbitone, pentobarbitone, phenobarbitone and quinalbarbitone blood concentrations are compared. 3 Combined alcohol-barbiturate blood concentration curves connecting those concentration pairs equally effective in causing death are used to quantify the increase in toxicity. The quantitative effects of alcohol appear to be greater with the shorter- and longer-acting barbiturates than with the intermediate-acting derivatives. The different modes of interaction are discussed in terms of the physico-chemical and pharmacokinetic properties of the drugs.