Relationship of plasma levels of chlordiazepoxide and metabolites to clinical response

The authors report on the relationship between the antianxiety effects of chronically administered chlordiazepoxide (CDX) and plasma levels of CDX and two of its metabolites, desmethylchlordiazepoxide (DMCDX) and demoxepam (DMX). Fifteen subjects with moderate to severe anxiety were studied in a double-blind, placebo-controlled, crossover design. Significant correlations were found between anxiety reduction and DMCDX and DMX plasma levels. No such correlation was observed between anxiety reduction and CDX levels. These data suggest that in chronically treated subjects, DMCDX and DMX have significant antianxiety properties which surpass those of CDX itself.