Statins are probably the best medications to reduce cholesterol level and also have associated anti-inflammatory activities. Both these properties lead to a marked decrease in atherosclerosis and related diseases.
Muscle pain is quite common in people (up to 10%) who take one of the several statins for lowering their cholesterol levels. However, there is no strict consensus on how to define, diagnose and manage such muscle pains.
The Annals of Internal Medicine recently published an excellent review on “Statin related myopathy.” Here is a brief summary of the article.
Definition:
There is no consensus definition. Each group (ACC/AHA, FDA etc) have their own definitions. For most clinical purposes the following definitions should be adequate:
Myopathy: Muscle disease with creatine kinase > 10 time upper limit
Rhabdomyolysis: Creatine kinase elevation with end organ damage
Pathophysiology:
Incompletely understood. Proposed mechanisms include:
- Decreased cholesterol content of skeletal myocyte membrane leading to instabilty
- Depletion of isoprenoids and/or coenzyme Q10
- Mitochondrial dysfunction
Risk factors for developing myopathy:
- Advanced age
- Smaller body size
- Multi-system diseases (including hypothyroidism)
- Alcoholism
- Major surgery, excess physical activity
- History of myopathy while on other lipid lowering agent
- Family history
- Higher doses of statin
- Interaction with other drugs leading to increased bio-availability of statins
Clinical Features:
Major site of muscle pain were in the thighs, calves or it was generalized. Pain was described as heaviness, stiffness or cramping and sometimes was associated with exertion. Physical exertion was a common trigger of myalgia. Tendon pain may also be present.
Management:
- Check creatine kinase (CK) levels in high risk patients
- If CK levels > 10 times upper limit, stop statin
- Re-initiate statin with a lower dose once CK levels return to normal
- Try switching to fluvastain (better tolerated) or rosuvastatin (less interaction with other medications)
- Atorvastatin and Rosuvastatin have long half life and can be administered on alternate days
- Trial of other lipid lowering agents (e.g. Bile acid binders, ezetimibe, niacin etc)
- Co-enzyme Q10 supplementation may tried. No clear benefit but is very safe.
