Silent Danger of Quetiapine Overdose Leading to Rhabdomyolysis: A Case Report

Quetiapine, an atypical antipsychotic, has various side effects, including the rare but severe complication of rhabdomyolysis. This report detailed a 32-year-old female with persistent depressive disorder (PDD) and major depressive episodes (MDE), who presented to the Emergency Department after a parasuicidal attempt involving an overdose of 8 mg of clonazepam and 4800 mg of quetiapine. She exhibited symptoms of dizziness, nausea and transient loss of consciousness, along with mild tachycardia, elevated urea and creatinine levels from her baseline. During hospitalisation, she complained of generalised body aches, especially in the lower limbs, and her creatine kinase (CK) level peaked at 10,691 IU/L. Intravenous fluid therapy led to a reduction in CK levels and normalisation of renal function, allowing for a stable discharge and psychiatric clinic follow-up. Quetiapine’s antagonism of serotonin receptors, particularly 5-HT2A, may alter muscle cell membrane permeability, contributing to elevated CK levels. Even at therapeutic doses up to 800 mg/day, quetiapine can elevate CK levels, yet routine CK testing is not standard, which can delay the diagnosis of quetiapine-induced rhabdomyolysis. This case underscores the necessity for vigilant monitoring and advocates for incorporating CK testing in the routine evaluation of quetiapine overdose, even without significant symptoms, to prevent severe complications of rhabdomyolysis.