Lipid Biochemistry USMLE Step 1 Practice Question
A 60-year-old woman with hypercholesterolemia taking atorvastatin presents with generalized myalgia and weakness for 3 days. Vital signs: BP 128/82, HR 92, RR 16, Temp 37.2°C, SpO2 98%. Creatine kinase is elevated at 5,200 IU/L; renal function remains normal with creatinine 0.9 mg/dL. Autoantibody panel is negative. She recently started clarithromycin for pneumonia. Which mechanism best explains the increased statin toxicity in this patient?
Answer choices
- AAdditive immunosuppression leading to statin-induced autoimmune myositis
- BDirect inhibition of HMG-CoA reductase by both clarithromycin and statin
- CClarithromycin-induced rhabdomyolysis with secondary statin accumulation in muscle
- DInhibition of CYP3A4 by clarithromycin, reducing statin metabolism and increasing serum levelsCorrect answer
- EEnhanced statin absorption through increased intestinal P-glycoprotein expression
- FClarithromycin-induced inhibition of hepatic UDP-glucuronosyltransferase, preventing conjugation and renal excretion of statin metabolites
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