THE ROLE OF THE HEPATIC CYTOCHROME-P450 ENZYMES IN PSYCHOPHARMACOLOGY

Nearly all psychotropic drugs are metabolized by hepatic cytochrome P4 50-enzymes. In humans,there are 5 isoenzymes involved in this process. The activity of these enzymes can be modulated by a number of commonl y used drugs,yielding potentially hazardous interactions. Most of the recently introduced selective serotonin reuptake inhibitors are potent inhibitors of cytochrome P450 enzymes. Thus, the plasma concentration s of tricyclic antidepressants or clozapine might be elevated into tox ic levels. In contrast, carbamazepine induces most of the isoenzymes. This potentiates the elimination of tricyclics and antipsychotics and might cause a serious risk for the reccurence of depressive or psychot ic symptoms. Moreover, 5-10% of the population are slow metabolizers o f CYP2D6. This group is prone to increased adverse effects of moderate ly dosed medication. This review systematically points out the reporte d or predicted pharmacokinetic drug interactions in psychopharmacology focussing on clinical significance.