CYP450 and Its Implications in the Clinical Use of Antipsychotic Drugs

Polypharmacy implies a high potential for drug-drug interactions. The capacity of the cytochrome P450 enzyme system involved in the metabolism of psychoactive drugs differs greatly, which leads to variable drug elimination rates and inter-subject differences in serum drug concentrations. Polymorphisms in genes coding for CYP450 enzymes contribute to this inter-subject variability. Therapeutic response and adverse effects vary among patients treated with the same dose of a certain drug. Polypharmacy, comorbidity and the use of certain substances (grapefruit juice, caffeine and tobacco) increase the chances of clinically relevant interactions in a psychotic patient. Choosing drugs with low interaction potential seems to be the best strategy to prevent clinically relevant interactions particularly in elderly, polymedicated, oncologic and HIV patients