Importance of oxidative polymorphism and levomepromazine treatment on the steady-state blood concentrations of clomipramine and its major metabolites

Abstract

The relationship between the debrisoquine oxidation status and the metabolism of clomipramine was studied in nine healthy volunteers (five rapid hydroxylators, three slow hydroxylators and one of intermediate status). The hydroxylation of clomipramine and demethylclomipramine were found to covary with that of debrisoquine, whereas demethylation of clomipramine seemed to be independent of the debrisoquine hydroxylation phenotype. The steady-state blood concentrations of clomipramine and its three main metabolites were measured in 122 depressed patients. Thirteen patients who concomitantly received a neuroleptic tended to have higher levels of demethylclomipramine and clomipramine, whereas the levels of the hydroxylated metabolites were hardly affected. Benzodiazepine co-administration did not modify the pharmacokinetics of clomipramine. The results suggest that benzodiazepines rather than levomepromazine should be used in depressed patients with anxiety and/or agitation in combination with the antidepressant treatment.