Delayed-Onset Severe Statin-Induced Rhabdomyolysis Due to Atorvastatin-Ticagrelor Interaction in a Patient With Acute Coronary Syndrome: A Case Report

Rhabdomyolysis is a rare but potentially life-threatening complication of statin therapy, typically occurring within days to weeks (mean onset approximately nine days) after initiation or dose escalation. Delayed-onset presentations after a period of uneventful use are uncommon and may delay diagnosis. We report a 62-year-old man with ischemic heart disease and chronic kidney disease (CKD stage 3a) who developed a five-day history of bilateral lower limb pain, difficulty ambulating, and dark-colored urine. During a routine post-percutaneous coronary intervention (PCI) follow-up visit, subtle lower limb weakness was incidentally noted by his cardiologist, prompting immediate referral to the emergency department for further evaluation. He had been initiated on high-intensity atorvastatin (80 mg daily) two months following PCI. There was no history of trauma, immobilization, or recent strenuous physical activity. Laboratory investigations revealed a creatine kinase level peaking at 245,550 U/L (normal <190 U/L) and a serum creatinine of 5.22 mg/dL (normal 0.7-1.2 mg/dL, patient baseline 1.6 mg/dL), consistent with severe rhabdomyolysis complicated by acute kidney injury. Urine dipstick testing was positive for blood, while microscopic examination showed few red blood cells, consistent with myoglobinuria rather than hematuria; the autoimmune myositis workup was negative. Atorvastatin was discontinued on admission, and the patient was managed with aggressive intravenous fluid resuscitation. Renal function initially worsened but subsequently recovered without the need for renal replacement therapy. This case highlights that statin-associated muscle toxicity can occur after a period of prior tolerance. It may present in a delayed fashion, particularly when a CYP3A4 inhibitor such as ticagrelor is co-administered. Early recognition and prompt withdrawal of the offending agent are essential to prevent severe complications. In patients requiring ongoing lipid-lowering therapy, consideration should be given to alternative agents with minimal CYP3A4 metabolism and lower potential for clinically significant drug interactions.