Subjective side effects of mianserin in relation to plasma concentrations of mianserin and desmethylmianserin.

The main purpose of the present study was to examine the possibility that plasma concentrations of mianserin and its metabolite, desmethylmianserin, might be predicted by recording subjective side effects. In 44 depressed patients, subjective side effects during 3 weeks of treatment with 30 mg of mianserin were evaluated by the UKU Side Effect Rating Scale, and their relationships to plasma concentrations of mianserin and desmethylmianserin were analyzed. There was no significant relationship between plasma concentrations of these compounds and the occurrence of mianserin-induced side effects, except for dryness of mouth during week one. Our study, therefore, suggests that it is difficult to predict plasma concentrations of mianserin and desmethylmianserin based on the occurrence of subjective side effects.