Statin Myopathy

Statin drugs, used for lowering cholesterol, are among the most commonly prescribed medications in the developed world. While statins are generally quite well-tolerated, the most common adverse effects are related to the skeletal muscles, a condition called “statin myopathy”.

Symptoms

Statin myopathy generally takes one of three forms:

• Myalgia: Muscle pain is the most common symptom experienced by people taking statins. Statin-induced myalgia is generally experienced as a soreness, usually in the shoulders and arms, or the hips and thighs. It is often accompanied by mild weakness.
• Myositis: Muscle inflammation caused by statins is characterized by muscle pain, as well as an elevation in creatine kinase (CK) levels in the blood. CK is a muscle enzyme, and its presence in the blood indicates that actual muscle damage is occurring.
• Rhabdomyolysis: Severe muscle injury can occur, leading to a large release of muscle protein into the bloodstream; this can lead to severe kidney damage and even death. Rhabdomyolysis caused by statins, fortunately, is very rare, occurring in less than one person per 100,000 treated with these drugs each year.

If muscle problems occur, they usually begin within a few weeks to a few months after starting statin therapy. Statin-related myalgia and myositis will usually both resolve within a few weeks if statin therapy is discontinued. Rhabdomyolysis will also resolve after the statin is stopped, but the damage it causes may be irreversible.

While there are several theories, nobody knows for sure why statins can produce muscle problems. Statin myopathy probably has to do with changes in how the muscles produce or process energy. So far, researchers have not been able to take it much further than that with any degree of confidence.

The theory that has gained the most traction with the public is that statins might interfere with the production of CoQ10, a coenzyme in the muscles. CoQ10 helps the muscles use the energy they need to function. Some small studies have suggested that taking CoQ10 supplements might reduce the incidence of statin-related muscle problems, but the data (both on whether statins actually reduce CoQ10 levels and on whether CoQ10 supplementation helps) is really quite weak​.

Recent studies have suggested that muscle problems with statins are more frequent in people who have vitamin D deficiency. Some have found that administering vitamin D to these people will help resolve their statin-related muscle symptoms.

Risk Factors

Muscle problems with statins are more common in people who are also taking Lopid (gemfibrozil), steroids, cyclosporine, or niacin.

People who have chronic kidney disease, liver disease, reduced vitamin D levels, or hypothyroidism are also more likely to experience muscle problems with statins, as are people who have preexisting muscle disease.

Some statins appear more likely to produce muscle problems than others. In particular, the incidence of muscle problems may be higher with high-dose simvastatin (brand name Zocor) than other statin drugs.

For this reason, in June 2011, the Food and Drug Administration recommended that the dose of simvastatin be limited to 40 mg per day. At this dose, the incidence of muscle problems with simvastatin does not appear to be especially high.

The risk of muscle problems appears to be substantially less with Lescol (fluvastatin), Pravachol (pravastatin) and probably Crestor (rosuvastatin). If mild muscle-related side effects occur with other statins, switching to one of these drugs can often resolve the problem.

Statin myopathy is somewhat more likely in people who engage in vigorous exercise, especially if they do so without building up to it gradually.

Treatment

Generally, if a statin-related muscle problem is suspected, healthcare providers will stop the statin drug, at least until the muscle problem resolves. An assessment should be done for vitamin D deficiency and hypothyroidism, as well as for any drug interactions that may increase statin-related muscle problems. Any of these risk factors that are identified should be dealt with.

If the muscle-related symptoms consisted only of pain and perhaps a small elevation in CK blood levels, and if continued statin therapy is deemed to be important, there are a few approaches that may allow the successful resumption of a statin.

First, switching to a statin that is particularly unlikely to cause muscle problems (such as pravastatin or fluvastatin) can often allow a person with previous muscle issues to take a statin successfully. Also, prescribing a statin drug every other day, instead of each day, has been helpful in some people who could not tolerate daily statin therapy. Finally, while most experts do not believe that CoQ10 supplementation is helpful in enabling resumption of statin therapy, there are scattered reports that this can be helpful.

A Word From Verywell

While muscle side effects are the most common problem seen with statins, these side effects are relatively infrequent in people who do not have additional risk factors. Furthermore, when they occur, muscle problems are almost always reversible. Life-threatening muscle problems from statins are extremely rare.

Still, if you are taking a statin drug you should be aware of the possibility of developing muscle pain or weakness, and if these symptoms occur you should let your healthcare provider know.