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 On suspicion of its contribution to rhabdomyolysis, olanzapine was immediately withdrawn.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.