A CASE REPORT OF AN ULTRA-RAPID METABOLIZER ON DEPOT FORMULATIONS OF RISPERIDONE AND HALOPERIDOL AND REFLECTIONS ON METABOLIC PATHWAYS

Abstract

Polycyclic aromatic hydrocarbons (PAH) in tobacco are potent inducers of Cytochrome P450 (CYP) 1A2, which metabolizes a plenty of drugs including antipsychotics such as olanzapine or clozapine. With regard to haloperidol and risperidone, CYP3A4 is supposed to be the major isoenzyme. We present the case of a 60-year old woman who suffered from chronic schizophrenia and smoked more than 40 cigarettes per day, which indicates that PAH also induces CYP3A4, causing ultrarapid metabolisation of risperidone and haloperidol with subtherapeutic drug levels both after oral or intramuscular depot administration.

Keywords

• risperidone
• haloperidol
• ultra-rapid metabolisation
• tobacco
• CYP3A4
• schizophrenia