Barbital and diazepam plasma levels during treatment of delirium tremens.

Plasma concentrations of barbital and diazepam were measured daily during a double-blind study of the efficacy of the two drugs in the treatment of delirium tremens and less severe clinical states. Treatment was estimated as satisfactory in the majority of cases; the present study deals with the satisfactory groups only. Both in the barbital group and in the diazepam group the same plasma level was seen in different clinical states. This result is discussed in relation to the theories about the aetiology of delirium tremens, and it is concluded that the data fits best with the assumption that delirium tremens is released from a withdrawal state, but once established, the delirious state is not interrupted by the drugs. The barbital concentrations were rather high, many at a level where non-alcoholics would show pronounced intoxication symptoms not seen in the present material. The diazepam concentrations on the other hand were low, often below a level where a cerebral effect is measurable in normal subjects. On this basis it is concluded, that the two drugs have different modes of action. Barbital may act by its cross-dependence properties with alcohol and thus diminish the withdrawal reaction, whereas diazepam may act by its anti-anxiety effect, but not in the doses here applied, by cross-dependence properties with alcohol. Finally, this hypothesis is discussed in relation to clinical experience in the treatment of delirium tremens.