Open AccessClozapine Serum Concentrations are Lower in Smoking than in Non‐Smoking Schizophrenic Patients
Author(s) -
Seppälä Niko H.,
Lein Esa V. J.,
Lehtonen MaijaLiisa,
Kivistö Kari T.
Publication year - 1999
Publication title -
pharmacology & toxicology
Language(s) - English
Resource type - Journals
eISSN - 1600-0773
pISSN - 0901-9928
DOI - 10.1111/j.1600-0773.1999.tb02016.x
Subject(s) - clozapine , metabolite , schizophrenia (object oriented programming) , medicine , cytochrome p450 , pharmacology , drug , pharmacokinetics , physiology , endocrinology , psychiatry , metabolism
Serum concentrations of clozapine and its main metabolite demethylclozapine were measured in 44 schizophrenic inpatients, of whom ten were non‐smokers and 34 smokers. When comparing their clozapine dose and body weight‐related serum drug levels, we found that clozapine and demethylclozapine concentrations were about 40% lower in the smoking than in the non‐smoking group, probably due to an inducing effect of smoking on the cytochrome P450 (CYP) 1A2, which is involved in the metabolism of clozapine. We conclude that dosage adjustment may be necessary in clozapine‐treated smokers.