Citalopram and Clozapine: Potential Drug Interaction

Letter to the Editor

Sir: Clozapine, an atypical antipsychotic agent, appears to
be metabolized, in part, by the cytochrome P450 (CYP) 1A2
and CYP3A3/4 enzymes. Clozapine’s side effects include sedation,
hypersalivation, constipation, seizures, weight-gain, and
clozapine-induced agranulocytosis. Citalopram is a newly released
selective serotonin reuptake inhibitor (SSRI) that is
thought to have a favorable drug interaction profile secondary to
weak or negligible inhibition of cytochrome P450 enzymes.