What is the management approach for a patient with proximal myopathy, significantly elevated Creatine Kinase (CK) levels, and skin changes, who has been taking Rosuvastatin (rosuvastatin) for about a year, despite having normal kidney function?

Management of Statin-Induced Myopathy in a Patient on Rosuvastatin

Rosuvastatin should be immediately discontinued in this patient with proximal myopathy, significantly elevated CK levels (6000), and skin changes, as these findings strongly suggest statin-induced myopathy that requires prompt intervention to prevent progression to rhabdomyolysis. 1, 2

Clinical Assessment and Diagnosis

• The combination of proximal myopathy, CK elevation to 6000 (>10 times upper limit of normal), and skin changes after one year of rosuvastatin therapy is highly suggestive of statin-induced myopathy 1, 2
• Normal kidney function is reassuring but does not rule out the risk of progression to rhabdomyolysis if the medication is continued 2
• Skin changes may represent dermatomyositis or another immune-mediated process that can be associated with statin use 2

Immediate Management Steps

• Discontinue rosuvastatin immediately to prevent further muscle damage and potential progression to rhabdomyolysis 1, 2
• Obtain thyroid-stimulating hormone (TSH) levels to rule out hypothyroidism as a contributing factor to myopathy 1
• Monitor CK levels weekly until they normalize 1
• Assess for other potential causes of myopathy including:
  • Other medications that may interact with rosuvastatin 1
  • Underlying autoimmune conditions 2
  • Consider testing for anti-HMG CoA reductase antibodies if immune-mediated necrotizing myopathy (IMNM) is suspected 2

Follow-up Management

• Once symptoms resolve and CK levels normalize, consider the following options for lipid management 3, 4:
  1. Trial of a different statin with lower myopathy risk (fluvastatin or pravastatin) at a low dose with gradual titration 3
  2. Intermittent dosing of a potent statin (e.g., rosuvastatin 5-10mg twice weekly) 4
  3. Combination of lowest tolerated statin dose with ezetimibe and/or bile acid sequestrants 3
  4. Non-statin lipid-lowering therapy if statins cannot be tolerated at all 4

Risk Factors for Statin-Induced Myopathy to Consider

• Female gender increases risk of statin-induced myopathy 1, 5
• Dosage of rosuvastatin (higher doses increase risk) 1, 2
• Potential drug interactions that may have increased rosuvastatin levels 1, 2
• Genetic factors affecting statin metabolism (e.g., SLCO1B1 variants) 5

Special Considerations

• If symptoms and CK elevations persist despite statin discontinuation, consider muscle biopsy to evaluate for immune-mediated necrotizing myopathy (IMNM), which would require immunosuppressive therapy 2
• The skin changes should be evaluated carefully as they may represent dermatomyositis or another immune-mediated process 6
• Even with normal kidney function, the patient should be monitored for development of acute kidney injury due to myoglobinuria 7, 6

Prevention of Future Episodes

• If statin therapy is attempted again, use the lowest effective dose of a statin with lower myopathy risk 1, 4
• Avoid concomitant medications that interact with statins 1, 2
• Consider regular monitoring of CK levels if statin therapy is reinitiated, especially during the first few months 1
• Educate the patient to report muscle symptoms promptly if they recur 1, 2