General Information About Zocor (Simvastatin)

Andrew Soundarajan

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, or 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.

Pivotal studies examining the effect of Zocor 20 to 40 mg saw the following findings with Zocor: 

  • It can lower LDL cholesterol by an average of 35%.
  • It can lower total cholesterol levels by an average of 25%.
  • It can lower triglycerides by an average of 10%.
  • It can increase HDL 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%

Zocor was approved for use by the Drug Administration (FDA) in December of 1991.

How Does Zocor Work?

Zocor binds to and inhibits the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, a major enzyme in the cholesterol synthesis pathway, This action subsequently reduces the amount of cholesterol made in the liver.

How Should Zocor be Taken?

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

Zocor 80 mg may cause increased muscle pain – including rhabodmyolysis – so this dose is typically not used unless you have tolerated it for a period of time without side effects.  

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

Who Should Not Take Zocor?

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 cyclosporine, gemfibrozil, danazol, or other medications that strongly inhibit a metabolic pathway, CYP3A4, you should not take Zocor.
  • Pregnancy. Zocor is categorized as a Pregnancy Category X. Zocor has been shown to cross the placental barrier in rats and there have been reports of miscarriages and fetal abnormalities in animal studies. Additionally, this has also been reported in pregnant women taking statin medications. If you are planning to become pregnant or are already pregnant and are taking Zocor, your healthcare provider will weigh the benefits of taking the medication on your health and the possible risks to your child.
  • Nursing. Zocor has been shown to cross into breast milk. It is not known what type of effect this can have on your child.

What Conditions Need to Be Monitored While Taking Zocor?

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 below, 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 will be potentially harmful to you. These medical conditions include:

  • 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 these levels 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 may 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.

What Types of Side Effects Can Zocor Cause?

The most common side effects include headache, abdominal pain, nausea, constipation, and upper respiratory tract infections. If you are experiencing any side effects from taking Zocor that become prolonged or bothersome, you should let your healthcare provider know.

As with other statins, a rare side effect – rhabdomyolysis - may also occur in individuals taking Zocor. Symptoms of rhabdomyolysis include muscle soreness and weakness, as well as soda-colored urine. Your risk of experiencing this side effects may occur if you are taking other medications, increased age, taking the 80 mg dose of Zocor, and other medical conditions. If you experience any symptoms of rhabdomyolysis, you should immediately notify your healthcare provider.

Are There Any Medications that Could Interact with Zocor?

Besides cyclosporine, gemfibrozil, and the other medications mentioned above, the following drugs may interact with Zocor -  increasing the likelihood of experiencing side effects. The following drugs may increase levels of Zocor or other medications in your body:

  • Cholesterol-lowering drugs (nicotinic acid, fibrates)
  • Certain heart medications – such as verapamil, diltiazem, amiodarone, amlodipine
  • Protease inhibitors
  • Colchicine
  • Coumadin (warfarin)

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.

The Bottom Line

Zocor is a commonly prescribed medication to that is used to improve your lipid profile and reduce your risk of dying from a heart attack or stroke. Zocor is also available in a generic form, allowing you to obtain this medication at a cheaper cost compared to brand name medication. Although effective, there are some side effects and drug interactions you should watch out for when taking Zocor. Therefore, you should make sure that you keep your appointments with your healthcare provider so he or she can monitor your progress on the medication.  


Zovor (Simvastatin) [package insert]. Merck: Whitehouse Station, NJ. Updated 3.2015.

Micromedex 2.0.  Truven Health Analytics, Inc. Greenwood Village, CO.  Available at:  Accessed February 10, 2016

The 4S Study Authors. Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian simvastatin survival study. Lancet  1994 Nov 19;344(8934):1383-9

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