What Is Simvastatin and How Does It Work?

Simvastatin (Zocor) is a, FDA approved prescription medication that is used along with a proper diet to help lower "bad" cholesterol and fats (such as LDL, triglycerides) and raise "good" cholesterol (HDL) in the blood. It belongs to a group of drugs known as "statins." Statins are medications that work by reducing the amount of cholesterol made by the liver. Lowering "bad" cholesterol and triglycerides and raising "good" cholesterol decreases the risk of heart disease and helps prevent strokes and heart attacks. This drug maybe used to treat other diseases and conditions. Your doctor may conduct liver function tests when using statins to monitor liver enzymes and other liver function.

  • In addition to eating a proper diet (such as a low-cholesterol/low-fat diet), other lifestyle changes that may help simvastatin medication work better include exercising, losing weight if overweight, and stopping smoking. Consult your doctor for more details.
  • This medication is available under the following different brand names: Zocor.

What Are Dosages of Simvastatin (Zocor)?

Dosages of Simvastatin (Zocor):

Adult and Pediatric Dosage Forms and Strengths


  • 5 mg
  • 10 mg
  • 20 mg
  • 40 mg
  • 80 mg
Dosage Considerations – Should be Given as Follows: Hypercholesterolemia (High Cholesterol)
  • Usual dosage range: 5-40 mg orally once/day
  • Initial: 10-20 mg orally once/day in the evening
  • Patients at high CHD risk: Start 40 mg/day
  • Children under 10 years: Safety and efficacy not established
Homozygous Familial Hypercholesterolemia (Genetic High Cholesterol)
  • Recommended dose: 40 mg orally once/day in the evening
  • See limitations for 80 mg/day, listed below
Heterozygous Familial Hypercholesterolemia (Genetic High Cholesterol)

Adolescents aged 10-17 years

  • Initial: 10 mg orally once/day in the evening; not to exceed 40 mg/day
  • Recommended dosing range: 10-40 mg/day; adjustments should be made at intervals of 4 weeks or more
Dosage Modifications
  • Severe renal impairment (CrCl less than 30 mL/min): 5 mg once/day initially
  • Co-administration with dronedarone, verapamil, or diltiazem: Do not exceed 10 mg/day
  • Co-administration with amiodarone, amlodipine, or ranolazine: Do not exceed 20 mg/day
  • Co-administration with lomitapide: Reduce dose by 50%, and do not exceed 20 mg/day (or 40 mg/day in those previously tolerating 80 mg/day) when initiating lomitapide
  • People of Chinese descent taking lipid-modifying doses of niacin (i.e., 1 g/day or more): Increased risk of myopathy with 40 mg/day; consider lower dose
  • People of Asian descent should not receive 80 mg co-administered with lipid-modifying doses of niacin-containing products
Dosing Considerations
  • Lipid determinations should be performed after 4 weeks of therapy and periodically thereafter

Restricted dosing

  • 80 mg/day should be used only for individuals who have been taking 0 mg chronically (e.g., 12 months or more) without evidence of myopathy or rhabdomyolysis
  • Patients tolerating 80 mg who need to be initiated on an interacting drug that is contraindicated or associated with a maximum dose should be switched to an alternative statin with less potential for drug-drug interactions
  • Patients unable to achieve their LDL cholesterol goal utilizing 40 mg/day should not be titrated to 80 mg (increased risk for disease of muscle tissue) but should instead be placed on alternative LDL- cholesterol-lowering treatment that provides greater LDL- cholesterol-lowering

Overdose management

  • Adverse side effects and drug reactions from overdose may include peripheral neuropathy, diarrhea, increased K+, myopathy, rhabdomyolysis, acute renal failure, elevated LFTs, and eye lens opacities
  • Treatment is supportive

What Are Side Effects Associated with Using Simvastatin?

Common side effects of simvastatin include:

Less common side effects of simvastatin include:

Postmarketing side effects of simvastatin reported include:

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Simvastatin?

If your doctor has directed you to use this medication for diabetes, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • This drug has severe interactions with at least 32 different drugs.
  • This drug has serious interactions with at least 79 different drugs.
  • This drug has moderate interactions with at least 79 different drugs.
  • Mild Interactions of simvastatin include:

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Simvastatin?


  • This medication contains simvastatin. Do not take Zocor if you are allergic to simvastatin or any ingredients contained in this drug.
  • Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


Effects of Drug Abuse

  • There are no known effects of drug abuse.

Short-Term Effects

  • See "What Are Side Effects Associated with Using Simvastatin?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Simvastatin?"


  • Non-serious and reversible cognitive side effects may occur.
  • Increased blood sugar and glycosylated hemoglobin (HbA1c) levels were reported with statin intake.
  • Heavy alcohol use, history of liver disease, renal failure.
  • Monitor LFTs before initiating treatment and thereafter when clinically indicated; reports of fatal and nonfatal hepatic failure in people taking statins.
  • Discontinue if markedly elevated CPK levels occur or myopathy is diagnosed or suspected.
  • Increases in HbA1c and fasting serum glucose levels were reported with simvastatin.
  • Severe electrolyte, endocrine, or metabolic disorders.
  • Grapefruit juice increases simvastatin systemic exposure; avoid large quantities of grapefruit juice (i.e., 1 quart/day or more).

Simvastatin and myopathy risk:

  • Dose adjustment required when co-administered with niacin, amiodarone, verapamil, diltiazem, amlodipine, and ranolazine
  • Predisposing factors for myopathy include advanced age (older than 65 years), uncontrolled hypothyroidism, and renal impairment
  • Increased risk for myopathy in Chinese people co-administered niacin greater than 1 g/day; they should not receive simvastatin 80 mg co-administered with lipid-modifying doses of niacin-containing products
  • Withhold or discontinue if myopathy, renal failure, or transaminase levels greater than 3x ULN develop
  • The risk of myopathy is greater in people taking simvastatin 80 mg/day, especially in the 1st year of treatment
  • Rare reports of immune-mediated necrotizing myopathy (IMNM), characterized by increased serum creatine kinase that persists despite discontinuing statin
  • Risk for myopathy increased when coadministered with other lipid-lowering drugs (other fibrates, 1 g/day of niacin or more, or, for patients with HoFH, lomitapide), colchicine, amiodarone, dronedarone, verapamil, diltiazem, amlodipine, or ranolazine
  • See Contraindications for list of drugs contraindicated because of increased risk for myopathy when co-administered with simvastatin
  • See Adult Dosing for dose limitations and modifications

Pregnancy and Lactation

  • Do not use this drug in pregnancy. The risks involved outweigh the potential benefits. Safer alternatives exist.
  • Simvastatin is contraindicated while breastfeeding; it is potentially unsafe.

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