Clinical effects related to the serum concentrations of thioridazine and its metabolites

Abstract

Neuroleptic drugs have vastly improved the treatment of psychotic disorders and increased our capacity to ameliorate severe symptoms and to rehabilitate patients. The first substance used, chlorpromazine, has been followed by a variety of others, mostly without major differences in antipsychotic activity. These drugs do, however, differ in respect to type and frequency of induced side-effects. Since some side-effects are concentration-dependent, it is important to keep both acute and maintenance doses minimal without loss of therapeutic effect. With the aid of routine serum determinations, we have therefore sought to optimize the treatment with a commonly used neuroleptic drug, thioridazine. Earlier studies of the metabolism (Mårtensson et al., 19/5), protein binding (Nyberg et al., 1978) and metabolite characteristics (Axelsson and Mårtensson, 1977) of this drug have provided the basis for the present study, in which our aim has been to explore any correlations between the serum concentrations of thioridazine and its metabolites on the one hand, and clinical effects, including side-effects, on the other.