Olanzapine-Associated Rhabdomyolysis: A Case Report

This paper presents the case of a 20-year-old patient with a suspected diagnosis of paranoid schizophrenia. He was prescribed oral olanzapine at a dose of 10 mg per day, and the treatment was associated with rhabdomyolysis (serum creatine kinase = 9,725 U/L on day four of the therapy). On suspicion of its contribution to rhabdomyolysis, olanzapine was immediately withdrawn. Pharmacogenetic testing demonstrated that the patient's CYP2D6 genotype was *4/*4 (1846G>A, rs3892097). Based on these results, the patient was switched to trifluoperazine, a medication that is not metabolized by the CYP2D6 isoenzyme. Subsequently, the patient recovered well and was discharged without any nephrological sequelae. The presented case demonstrates that pharmacogenetic-guided personalization of treatment may allow selecting the best medication and determining the right dosage, resulting in the reduced risk of adverse drug reactions and pharmacoresistance.