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Statin-Induced Myopathy
Aka: Statin-Induced Myopathy, Rhabdomyolysis due to Statin, Statin-Induced Myalgias, Myositis due to Statins, Statin Myopathy
- See Also
- Statin
- Epidemiology
- Statin-Induced Myalgias are common (5-30%)
- Statin-induced Rhabdomyolysis is very uncommon (<0.01%)
- Davidson (2006) Am J Cardiol 97(8A):32C–43C [PubMed]
- Mendes (2014) Physiother Can 66(2): 124–132 [PubMed]
- Mechanism
- Typical Myopathy
- Muscle injury secondary to Statin use (drug-induced Myopathy - accelerating Muscle Cell death)
- Statin-Induced Immune-mediated Necrotizing Myopathy
- Newly defined in 2011
- Symptoms and findings (including CPK) remain abnormal after stopping the Statin
- Symptoms
- Myalgia
- Muscle ache or weakness with normal CPK
- Myostitis
- Muscle ache or weakness with CPK elevated but <10 fold increase above normal
- Rhabdomyolysis
- Muscle ache or weakness with CPK elevated but >10 fold increase above normal
- Symptoms: Red Flags
- Patient should stop Statin and contact physician if following symptoms experienced
- Severe myalgias
- Muscle Weakness
- Dark Urine
- Labs
- Creatine Phosphokinase (CPK)
- Poor marker for myalgias (only increased in Myositis or Rhabdomyolysis)
- Normal in most patients despite myalgias
- Abnormal CPK suggests Myositis or Rhabdomyolysis and requires immediate cessation of Statin
- Additional labs in CPK Elevation (especially Rhabdomyolysis)
- Urine Myoglobin
- Renal Function
- Labs to consider in differential diagnosis
- Vitamin D Level
- Thyroid Stimulating Hormone (TSH)
- Differential Diagnosis
- See Myopathy Causes
- Vitamin D Deficiency
- Hypothyroidism
- Risk factors: Statin induced Myopathy
- Statin combination with Gemfibrozil (and to a lesser extent with Fenofibrate)
- Drug Interactions (see Statins)
- Raised serum Statin levels result in higher myalgia or Myositis risk
- Older patients over age 70 years
- Low body weight
- Female gender
- Acute illness or major surgery
- Alcohol Abuse or other Substance Abuse (e.g. Cocaine, Amphetamines)
- Hypothyroidism
- Chronic Kidney Disease Stage 4 (Creatinine Clearance <30 ml/min)
- High dose Statin use (dose greater than 50% of maximum dose, especially Simvastatin 80 mg)
- Management: Symptomatic
- Coenzyme Q10 (Ubiquinone) 100 mg orally daily
- Reduces myalgias by 40% in one study (other studies show no efficacy)
- Caso (2007) Am J Cardiol 99:1409-12 [PubMed]
- Decrease Statin dose by 50%
- Consider alternate day dosing or twice weekly dosing
- Consider Ezetimibe as an adjunct to allow lowering Statin dose
- Consider change to alternative Statin
- Initially thought that hydrophilic Statins (Pravastatin, Rosuvastatin) were less likely to cause myalgias
- Hydrophilic Statins do not appear to offer any increased benefit over other Statins regarding myalgia risk
- Thompson (2003) JAMA 289(13): 1681-90 [PubMed]
- References
- Bruckert (2005) Cardiovasc Drugs Ther 19(6): 403-14 [PubMed]
- Graham (2004) JAMA 292(21): 2585-90 [PubMed]
- Phillips (2002) Ann Intern Med 137:581-5 [PubMed]