Zocor Myopathy & Rhabdomyolysis

Zocor was developed in 1991 to treat cholesterol. It belongs to an anti-cholesterol group called statins. These medications are designed to reduce the patient’s levels of low-density lipoprotein (LDL) cholesterol. By lowering levels of LDL cholesterol, Zocor helps to reduce the risk of heart attack, stroke, and cardiovascular death in patients.

While Zocor has helped a number of patients lower their LDL cholesterol levels, the drug has also caused severe side effects. Patients have reported debilitating muscular diseases. These include myopathy and rhabdomyolysis, which can cause kidney failure and death if left untreated. A number of other Zocor side effects have been reported, such as memory loss, liver damage, and type 2 diabetes.

Zocor Myopathy

A number of patients have reported the onset of Zocor myopathy.  Zocor myopathy is most common in patients taking the highest dosage of 80 milligrams per day. Myopathy is a muscular condition during which the patient’s muscles fail to function properly. As a result, the patient experiences muscular weakness. In Greek, the term myopathy translates to “muscle suffering.”

Patients who believe they may suffer Zocor myopathy should seek immediate emergency medical attention. Severe Zocor myopathy symptoms may be present in patients who experience difficulty swallowing, slurred speech, sudden weakness in one side of the body, or difficulty raising the foot and toes.

Other Zocor myopathy symptoms may include:

  • Cramps
  • Stiffness or rigidity
  • Weakness
  • Swelling and inflammation
  • Paralysis
  • Tetany, or spasms
  • Atrophy, or wasting

Zocor Rhabdomyolysis

In severe cases, myopathy can develop into Zocor rhabdomyolysis. During Zocor rhabdomyolysis, the patient’s muscle tissue begins to break down rapidly. In healthy patients, muscle breakdown in normal levels does not pose serious health risks. When muscle breakdown occurs, the muscles produce byproducts such as myoglobin. These byproducts are then filtered out of the bloodstream by the patient’s kidneys.

In normal levels, these muscular byproducts do not cause harm to the kidneys. However, high levels of myoglobin and other muscular byproducts can cause harm. During Zocor rhabdomyolysis, the excessive byproduct levels cause kidney damage. If Zocor rhabdomyolysis progresses and fails to receive proper treatment, the patient may experience kidney failure and death.

Patients with Zocor rhabdomyolysis may experience:

  • Dark or reddish urine
  • Decreased urine production
  • Myalgia, or muscle aching and stiffness
  • Tenderness and weakness in affected muscles
  • Nausea or vomiting
  • Malaise, or general feelings of illness

Diagnosis and Treatment

It is essential to diagnose cases of Zocor myopathy and rhabdomyolysis. With proper and immediate medical treatment, patients may experience full recovery. Medical professionals can conduct a series of tests to determine if a patient is at-risk for damage from these conditions. Testing may be used to determine levels of specific enzymes and proteins in the blood. Testing of blood myoglobin, or serum myoglobin, may be conducted to determine if the patient has high levels of myoglobin. This may indicate excessive muscle breakdown that can lead to kidney damage.

Depending on the severity of the patient’s Zocor myopathy and rhabdomyolysis, the patient may need to be carefully monitored in a hospital’s intensive care unit. Intravenous (IV) fluids may be administered to prevent dehydration and kidney failure. The patient typically requires ongoing treatment to maintain adequate urine production. In the event that kidney failure occurs, the patient will undergo dialysis treatment to filter the blood.

Zocor FDA Warnings

In March 2010, the FDA disseminated a news release discussing the increased risk of developing muscle injury while taking the 80 milligram dose of Zocor. In the news release, the FDA notes that while myopathy and other muscle injury is a known side effect of cholesterol-lowering drugs, Zocor poses a higher risk. Additionally, the release notes the risk and severity of developing rhabdomyolysis. The FDA gathered this information from a variety of sources. These sources include observational studies, clinical trials, prescription use data, and adverse event reports from patients.

View Sources


  • Egan, Amy, and Eric Colman. “Weighing the Benefits of High-Dose Simvastatin against the Risk of Myopathy.” New England Journal of Medicine. 365. (2011): 285-287. Web. 15 May 2013. https://www.nejm.org/doi/full/10.1056/NEJMp1106689
  • “FDA announces new safety recommendations for high-dose simvastatin.” U.S. Food and Drug Administration. U.S. Department of Health and Human Services, 8 Jun 2011. Web. 15 May 2013. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm258338.htm
  • Federman, Daniel G., Fauzia Hussain, and Janie B. Walters. “Fatal rhabdomyolysis caused by lipid-lowering therapy.” Southern Medical JournalOct. 2001: 1023+. Academic OneFile. Web. 15 May 2013.
  • “Simvastatin: Myopathy risk. (Safety labeling updates & new warnings).” Formulary July 2002: 337. Academic OneFile. Web. 15 May 2013.
  • Stankovic, Ivan, et al. “Concomitant Administration of Simvastatin and Danazol Associated with Fatal Rhabdomyolysis.” Clinical therapeutics 32.5 (2010): 909-14. ProQuest. Web. 15 May 2013.