Skip to main content


Generic name: niacin and simvastatinNYE-a-sin-and-SIM-va-stat-in ]
Drug class: Antihyperlipidemic combinations

Medically reviewed by Philip Thornton, DipPharm. Last updated on Feb 7, 2023.

What is Simcor?

Simcor contains a combination of niacin and simvastatin.

Simcor is used to lower cholesterol and triglycerides (types of fat) in the blood. Simcor is used along with diet to lower levels of total cholesterol, LDL "bad" cholesterol, and triglycerides and to increase HDL "good" cholesterol.

Niacin, also called nicotinic acid, is a B vitamin (vitamin B3). It occurs naturally in plants and animals, and is also added to many foods as a vitamin supplement. Niacin is also present in many multiple vitamins and nutritional supplements.

Simvastatin is in a group of drugs called HMG CoA reductase inhibitors, or "statins." Simvastatin reduces levels of "bad" cholesterol (low-density lipoprotein, or LDL) and triglycerides in the blood, while increasing levels of "good" cholesterol (high-density lipoprotein, or HDL).


You should not take Simcor if you are allergic to niacin or simvastatin, or if you have liver disease, stomach ulcer, or severe bleeding.

Do not use Simcor if you are pregnant.

Do not breast-feed while using this medicine.

The following drugs should not be used while you are taking Simcor: cyclosporine, danazol, nefazodone, gemfibrozil; clarithromycin, erythromycin, telithromycin; fluconazole, itraconazole, ketoconazole, posaconazole; amiodarone, diltiazem, verapamil; boceprevir, telaprevir; atazanavir, cobicistat, darunavir, delavirdine, fosamprenavir, indinavir, nelfinavir, ritonavir, saquinavir, or tipranavir.

Before taking this medicine

You should not take Simcor if you are allergic to niacin (Niaspan, Niacor, and others) or simvastatin (Zocor, Vytorin), or if you have:

  • liver disease;

  • stomach ulcer;

  • severe bleeding; or

  • if you are pregnant or breastfeeding.

Simvastatin can cause a condition that results in the breakdown of skeletal muscle tissue, leading to kidney failure. This condition may be more likely to occur in women and older adults and in people who have kidney disease or poorly controlled hypothyroidism (underactive thyroid).

The following drugs can increase your risk of serious muscle problems if you take them together with simvastatin. These drugs should not be used while you are taking Simcor:

  • cyclosporine;

  • danazol;

  • gemfibrozil;

  • nefazodone;

  • an antibiotic - clarithromycin, erythromycin, telithromycin;

  • antifungal medicine - fluconazole, itraconazole, ketoconazole, posaconazole;

  • heart or blood pressure medicine - amiodarone, diltiazem, verapamil;

  • hepatitis C medications - boceprevir, telaprevir; or

  • HIV or AIDS medication - atazanavir, cobicistat, darunavir, delavirdine, fosamprenavir, indinavir, nelfinavir, ritonavir, saquinavir, tipranavir.

Before you start taking Simcor, tell your doctor if you are already using any of these other medicines:

  • amlodipine; or

  • ranolazine.

To make sure Simcor is safe for you, tell your doctor if you have ever had:

  • liver or kidney disease;

  • diabetes;

  • gout;

  • a thyroid disorder; or

  • if you drink more than 2 alcoholic beverages daily;

  • or if you are switched to this medication from regular niacin, nicotinic acid, or nicotinamide (or vitamin supplements that contain niacin).

Simcor can harm an unborn baby or cause birth defects. Do not take Simcor if you are pregnant. Stop taking this medication and tell your doctor right away if you become pregnant. Use effective birth control to avoid pregnancy while you are taking this medicine.

Niacin and simvastatin may pass into breast milk and could harm a nursing baby. Do not breastfeed while you are taking niacin and simvastatin.

How should I take Simcor?

Take Simcor exactly as prescribed. Follow all directions on your prescription label. Never take this medicine in larger amounts, or for longer than recommended by your doctor. Taking too much of this medication may cause serious or life-threatening side effects.

Simcor is usually taken at bedtime with a low-fat snack. Follow your doctor's instructions. Do not take this medicine on an empty stomach.

Do not crush, chew, or break an extended-release tablet. Swallow it whole.

Niacin can cause certain side effects such as dizziness, sweating, chills, flushing (warmth, redness, or tingly feeling under your skin), fast or pounding heartbeats, shortness of breath, or feeling like you might pass out. These effects can be made worse if you drink alcohol or hot beverages shortly after you take Simcor. These effects should disappear over time as you keep taking the medicine.

Your doctor may recommend you take aspirin 30 minutes before you take Simcor to prevent certain side effects. Do not take aspirin without your doctor's advice. Follow the label directions or your doctor's instructions about how much aspirin to take.

You may need to stop using Simcor for a short time if you have:

  • uncontrolled seizures;

  • an electrolyte imbalance (such as high or low potassium levels in your blood);

  • severely low blood pressure;

  • a severe infection or illness;

  • dehydration; or

  • surgery or a medical emergency.

If you stop taking Simcor for longer than 7 days in a row, talk with your doctor before restarting the medication. You may need to start with a lower dose.

Niacin can raise your blood sugar, and may cause unusual results with certain medical tests. Tell any doctor who treats you that you are using this medicine.

While using this medicine, you may need frequent blood tests.

You may need to take Simcor on a long-term basis for the treatment of high cholesterol. Do not stop taking this medication unless your doctor tells you to.

Store at room temperature away from moisture and heat.

Dosing information

Usual Adult Dose for Hyperlipidemia:

Initial (for patients not currently on niacin extended-release and patients currently on niacin products other than niacin extended-release): 500 mg-20 mg orally once daily at bedtime with a low fat snack.

Patients already taking simvastatin 20 to 40 mg who need additional management of their lipid levels may be started on a Simcor dose of 500 mg-40 mg once daily at bedtime.

Maintenance (depending on patient tolerability and lipid levels): 1000 mg-20 mg to 2000 mg-40 mg once daily at bedtime with a low fat snack

The dose of niacin extended-release should not be increased by more than 500 mg daily every 4 weeks. The efficacy and safety of doses of Simcor greater than 2000 mg-40 mg daily have not been studied and are therefore not recommended. If therapy is discontinued for an extended period of time (greater than 7 days), re-titration as tolerated is recommended.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What to avoid

Grapefruit and grapefruit juice may interact with simvastatin and lead to potentially dangerous effects. Do not drink more than 1 quart of grapefruit juice daily.

If you also take cholestyramine (Prevalite, Questran) or colestipol (Colestid), avoid taking them within 4 to 6 hours before or after you take Simcor.

Avoid eating foods that are high in fat or cholesterol. Simcor will not be as effective in lowering your cholesterol if you do not follow a cholesterol-lowering diet plan.

Avoid drinking alcohol. It can raise triglyceride levels and may increase your risk of liver damage.

Simcor side effects

Get emergency medical help if you have any of these signs of an allergic reaction to Simcor: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

In rare cases, simvastatin can cause a condition that results in the breakdown of skeletal muscle tissue, leading to kidney failure. Call your doctor right away if you have unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.

Stop taking this medicine and call your doctor at once if you have:

  • confusion, memory problems;

  • swelling, weight gain, little or no urinating;

  • liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

  • high blood sugar - increased thirst, increased urination, hunger, dry mouth, fruity breath odor, drowsiness, dry skin, blurred vision, weight loss.

Common Simcor side effects may include:

  • headache;

  • back pain;

  • nausea, diarrhea;

  • flushing (warmth, redness, or tingly feeling); or

  • mild itching.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Simcor?

Tell your doctor about all medicines you use, and those you start or stop using during your treatment with Simcor, especially:

  • fenofibric acid, fenofibrate; or

  • a blood thinner (warfarin, Coumadin, Jantoven).

This list is not complete and many other drugs can interact with niacin and simvastatin. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Simcor only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.