SHM Converge Scientific Abstract ePoster Gallery-Can Rifaximin Trigger Rhabdomyolysis Despite Long Term Use of Atorvastatin?

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This case report asks whether rifaximin may contribute to rhabdomyolysis in a patient who had tolerated atorvastatin for many years.<br /><br />A 72-year-old man with hypertension, diabetes, CAD, and end-stage liver disease was admitted after a fall and 3 weeks of worsening generalized weakness. He had diarrhea from lactulose and poor oral intake. He had been taking atorvastatin 40 mg daily for 10 years, and rifaximin had been added 2 months earlier. Initial labs showed marked elevations in AST, ALT, BUN, creatinine, lactate, and high-sensitivity troponin, suggesting possible dehydration, AKI, liver injury, and cardiac injury. He was initially treated with IV fluids and other supportive care, and cardiology felt he had a type II NSTEMI.<br /><br />Because of persistent weakness and unexplained lab abnormalities, a CK was checked and was found to be 16,236 U/L, confirming rhabdomyolysis. Atorvastatin was stopped and the patient was aggressively hydrated. His weakness, renal function, and liver tests improved over 5 days.<br /><br />The authors note that statin myopathy is usually early and uncommon, but late-onset cases can occur even after years of use. Risk increases with interacting drugs that affect cytochrome P-450 metabolism. Atorvastatin is metabolized by CYP3A4. Although rifaximin does not clearly inhibit CYP3A4, it has been shown in vitro to be a substrate, and prior studies have reported more myopathy when rifaximin is combined with high-dose simvastatin. This raises the possibility that rifaximin may have contributed to the delayed rhabdomyolysis in this patient.<br /><br />The report emphasizes that rhabdomyolysis should be considered in patients with unexplained weakness, AKI, elevated liver enzymes, and troponin, and that CK should be ordered separately because high-sensitivity troponin can distract from the diagnosis.

Asset Subtitle

Ruwan Gamarallage

Meta Tag

Author List Ruwan Gamarallage, Sanjay N. Adi

Category Clinical Vignettes

Concept Statin-Induced Myopathy

Concept Rhabdomyolysis

Concept Statin-Induced Rhabdomyolysis

Concept Drug Interaction

Concept Creatine Kinase

Distinguished Non-Finalist

Presenter Organization Duke Raleigh Hospital

Presenting Author Ruwan Gamarallage

Track Adult

Keywords

rifaximin

rhabdomyolysis

atorvastatin

statin myopathy

creatine kinase

acute kidney injury

liver disease

weakness

drug interaction

cytochrome P450

Statin-Induced Myopathy

Rhabdomyolysis

Statin-Induced Rhabdomyolysis

Drug Interaction

Creatine Kinase