Usefulness of Therapeutic Drug Monitoring and Pharmacogenetics for a Patient Treated with Olanzapine, Buspirone, and Fluvoxamine: A Case Study.

Background: A patient, with a mental disorder caused by an intracranial infection, treated with olanzapine, fluvoxamine, and buspirone. The plasma exposure of olanzapine was too high at standard doses, with evidence indicating that it was caused by drug-drug interactions.

Methods: Using pharmacogenomics and therapeutic drug monitoring to guide drug dose adjustment for a patient in clinical practice.

Results: The patient underwent pharmacogenetic testing in addition to therapeutic drug monitoring as part of a pharmacist-led comprehensive evaluation of medication therapy management in a clinical setting, resulting in improved clinical efficacy that allowed discharge from a psychiatric hospital.

Conclusions: This case study demonstrates that therapeutic drug monitoring combined with pharmacogenetic-guided dose adjustment can aid in the management of patients receiving complex pharmacological treatments.