Statin Induced Muscle Toxicity
Risk of myopathy appears to be lowest with: fluvastatin, pravastatin, pitavastatin
Risk of muscle injury - Statins extensively metabolized by CYP3A4: lovastatin, simvastatin, atorvastatin
Clinical Presentation: Elevations of serum creatine kinase with proximal myalgia and weakness without skin involvement
Duration: The onset of muscle symptoms: weeks to months after the initiation of statin therapy / may occur at any time during treatment
Symptoms - Statin-induced myalgia/myopathy: proximal symmetric muscle weakness, soreness, myalgia, myositis, rhabdomyolysis, Difficulty raising the arms above the head, arising from a seated position, or climbing stairs; fatigue or tiredness, myoglobinuria
Diagnosis:
 - CK: SAMS <20,000 IU/I, IMNM: 1,000-20,000 IU/I
 - SAMS clinical index (SAMS-CI)
 - Muscle biopsy if symptoms do not resolve after DC Statin
 - EMG shows small-amplitude motor-unit potentials with increased spontaneous activity
TREATMENT:
 - Stop statin
 - Oral steroid, methotrexate, intravenous immunoglobulin (IVIG), and/or rituximab

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