Tug of war between clozapine and CYP450 inducers: A case report

The management of schizoaffective disorder bipolar type often involves a combination of pharmacotherapy and psychotherapy. Clozapine, an effective antipsychotic for treatment-resistant schizophrenia, and oxcarbazepine, a mood stabilizer, is a commonly prescribed medication. We present a case report of a 56-year-old male with schizoaffective disorder bipolar type who experienced subtherapeutic clozapine levels despite dose adjustments, leading to deteriorating symptoms. Oxcarbazepine, a weak CYP450 inducer, likely contributed to the subtherapeutic levels. Additionally, the pharmacogenetic analysis revealed a CYP1A2 *1F/*1F genotype, indicating normal activity with a potential for decreased serum levels and adverse events in the presence of inducers. The patient was eventually stabilized on a regimen of lithium, paliperidone, and quetiapine, avoiding oxcarbazepine. This case highlights the importance of considering individual patient factors, including pharmacogenetics when managing treatment-resistant patients. Monitoring serum clozapine levels and assessing enzyme activity before initiating therapy may help optimize treatment outcomes and minimize adverse events.