What to Know About Zocor (Simvastatin)

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Zocor (simvastatin) is a cholesterol-lowering medication that belongs to the statin class of drugs. It is used to treat elevated total cholesterol levels, LDL cholesterol, triglyceride, and apolipoprotein B levels in individuals diagnosed with primary hyperlipidemia or mixed dyslipidemia in cases where diet, lifestyle changes, and other medications are not completely lowering lipid levels.

Additionally, Zocor is used to reduce the risk of having a heart attack and stroke in individuals with or without cardiovascular disease.

Simvastatin package of pills with one pill out of the foil on a white background

Zocor is also available in a generic form, allowing you to obtain simvastatin at a lower cost compared to the brand-name product.


Zocor is used to reduce cholesterol and reduce your risk of death from a heart attack or stroke. It works by binding to and inhibiting the enzyme called 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, which the body uses to make cholesterol made in the liver.

The approval of Zocor by the U.S. Food and Drug Administration (FDA) in 1998 was based on foundational studies examining the effect of the drug at 20- to 40-milligram (mg) doses.

Among them was the Scandanavian Simvastatin Survival Study, a landmark trial that involved 4,444 adults with angina pectoris or a previous heart attack who were given Zocor for an average of 5.4 years. Among the findings:

  • Zocor lowered LDL ("bad") cholesterol by an average of 35%.
  • Zocor lowered total cholesterol levels by an average of 25%.
  • Zocor lowered triglycerides by an average of 10%.
  • Zocor increased HDL ("good") cholesterol levels by an average of 8%.

Zocor has also been shown in studies to reduce death due to cardiovascular disease by up to 42%.

Before Taking

If you are taking Zocor, your healthcare provider may need to monitor you more closely if you have certain medical conditions.

If you have any of the following conditions, your healthcare provider may decide to start you on Zocor at a lower dose and will need to monitor you to determine whether or not taking Zocor may be harmful to you:

  • Elevated liver enzymes: In studies, Zocor increased the liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in studies. Although in most cases this increase is temporary, your healthcare provider will monitor you to make sure that your liver enzymes are not elevated to dangerous levels.
  • Elevated blood glucose levels: Studies have shown that Zocor may increase hemoglobin A1C and fasting glucose levels. If you have diabetes, your healthcare provider will need to monitor these components in your blood and adjust your dose of Zocor.
  • Kidney disease: Your healthcare provider will start you at the lowest dose and monitor you closely.


If you have one of the medical conditions listed below, you should not take Zocor. In these cases, your healthcare provider may place you on a different treatment to lower your lipids:

  • Allergies: If you have had a previous allergy to Zocor or any of its ingredients, you should not take this medication.
  • Active liver disease: If you have active liver disease or unexplained, abnormally elevated liver enzyme levels, Zocor should not be taken.
  • Certain medications: If you are taking Sandimmune (cyclosporine), Lopid (gemfibrozil), Danocrine (danazol), or other medications that inhibit the same metabolic pathway that Zocor uses (CYP3A4).
  • Pregnancy: Animal studies have strongly linked Zocor (and all statin drugs) to miscarriages and fetal abnormalities. If you are planning to become pregnant or already are, tell your healthcare provider.
  • Lactation: Zocor has been shown to cross into breast milk. It is not known what type of effect this can have on a child, but breastfeeding should be avoided if you are on Zocor.


Zocor is taken by mouth, with or without food once a day, as directed by your healthcare provider. Although typical doses range from 5 mg to 40 mg, your healthcare provider may start you on a lower dose and slowly increase your dose based upon your LDL levels and response to the medication.

Patients are no longer titrated up to 80 mg due to side effects; however, if you are already taking 80 mg, and have been tolerating it without muscle pain for over 12 months, you may continue with your doctor's approval.

A lipid-lowering diet should be followed while you are taking Zocor.

Side Effects 

The most common side effects of Zocor include:

  • Headache
  • Abdominal pain
  • Nausea
  • Constipation
  • Upper respiratory tract infection

If you are experiencing any side effects from taking Zocor that become prolonged or bothersome, you should let your healthcare provider know.

Myopathy, such as rhabdomyolysis, is a rare side effect of Zocor and other statins. This is the breakdown of muscle tissue that results in the release of myoglobin (a protein) into the blood, which can cause kidney damage.

Symptoms of rhabdomyolysis include muscle soreness and weakness, as well as soda-colored urine. If you experience any of these, you should immediately notify your healthcare provider.

Your risk of experiencing side effects may occur if you are older, are taking the 80-mg dose of Zocor, or are taking a strong CYP3A4 inhibitor.

Warning and Interactions

Besides strong CYP3A4 inhibitors like Sandimmune, Lopid, and Danocrine, the following drugs may interact with Zocor by either increasing the concentration of a drug (and the risk of side effects) or decreasing the concentration of a drug (and lowering its efficacy):

  • Cholesterol-lowering drugs, including nicotinic acid and fibrates
  • Certain heart medications, such as Verelan (verapamil), Tiazac (diltiazem), Pacerone (amiodarone), and Norvasc (amlodipine)
  • Colcrys (colchicine)
  • Coumadin (warfarin)
  • Protease inhibitors, like Kaletra (lopinavir/ritonavir)

Since this is not a complete list, you should let your healthcare provider know of all medications—including herbal medications and over-the-counter drugs—that you are taking while taking Zocor.

If you are required to take one of the drugs listed above, your healthcare provider may need to adjust your dose, monitor you more closely for side effects, or discontinue one of the drugs.

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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