10 Simvastatin Interactions You Should Know About

Whether you’re picking up your first simvastatin (Zocor, FloLipid) prescription or you’ve been taking it for years, interactions are a significant factor to consider. From the foods you eat to other medications you take — some combinations can have serious effects.

Simvastatin has a lengthy list of interactions, from certain antibiotics and blood pressure medications to grapefruit juice. Fortunately, most of these can be addressed ahead of time after a pharmacist review of your current medication list. But it’s still important to know which interactions can cause problems and what you can do to manage them.

While it’s not a comprehensive list, below are 10 notable simvastatin interactions you should be aware of.

Promotion disclosure

Simvastatin

Avg retail price

$435.60(Save 97.21%)

GoodRx discount

$12.14

See all discounts

How it works

Use GoodRx to find medications, pharmacies, and discounts.

GoodRx discounts can help you pay less for your prescription.

Bring your free coupon or savings card to the pharmacy.

1. Antifungal medications like itraconazole

Azoles are a type of antifungal medication. Certain azoles can interfere with how your body breaks down (metabolizes) simvastatin. This reaction can lead to an increased risk of side effects from simvastatin, such as muscle pain. In some cases, serious muscle damage (called rhabdomyolysis) that results in kidney failure is also possible.

Examples of azoles that can interact with simvastatin include:

• Itraconazole (Sporanox, Tolsura)

• Ketoconazole

• Voriconazole (Vfend)

• Posaconazole (Noxafil)

Azoles can be taken by mouth, infused into a vein, or applied topically (e.g., as a cream applied to the skin). Topical azoles are less likely to interact with simvastatin.

If you need to take an antifungal medication, your healthcare provider may tell you to stop taking simvastatin until after you finish your antifungal treatment.

2. Antibiotics like erythromycin

Macrolides are a class of antibiotics used to treat a variety of infections. But some of them, like erythromycin and clarithromycin, can interact with simvastatin. Similar to azole antifungals, this interaction can increase the risk of simvastatin side effects.

If you’re prescribed one of these antibiotics to treat an infection, your provider may tell you to stop taking simvastatin until you have completed your treatment.

3. Certain antiviral medications

Some antiviral medications can interfere with how your body breaks down simvastatin, raising the risk of side effects. These include the following medications, which may be available on their own or in combination pills:

• HIV medications, such as nelfinavir (Viracept) and ritonavir (Norvir)

• Hepatitis C medications, such as boceprevir and telaprevir

• Nefazodone

You’ll usually take these antiviral medications long term. In this case, your provider may  prescribe you a different statin with a lower interaction risk.

4. Calcium channel blockers like amlodipine

Calcium channel blockers (CCBs) are used to treat high blood pressure and other heart conditions. When taken with simvastatin, certain CCBs can increase the risk of side effects like muscle damage. But unlike the must-avoid interactions covered above, you might be able to take a lower simvastatin dose to lower the risk of negative side effects.

Amlodipine (Norvasc), diltiazem (Cardizem), and verapamil are CCBs that can interact with simvastatin. If you’re taking amlodipine, it’s recommended not to exceed 20 mg of simvastatin daily. And if you’re taking diltiazem or verapamil, you shouldn’t take more than 10 mg of simvastatin daily. Your healthcare provider can decide on the best dose for you.

If you’re taking a CCB with simvastatin, inform your provider immediately if you develop muscle pain with weakness and tea-colored urine. These are possible indicators of rhabdomyolysis.

5. Heart rhythm medications like amiodarone

Heart rhythm medications, such as amiodarone (Pacerone), treat arrhythmias (abnormal heart rhythms). Similar to CCBs, they increase the risk of muscle damage when combined with simvastatin. They also have recommended dose adjustments if you take them together.

If you’re taking dronedarone (Multaq), it’s recommended not to take more than 10 mg of simvastatin daily. And you shouldn’t take more than 20 mg of simvastatin daily if you’re taking amiodarone. Be sure to confirm the correct dosage with your healthcare provider.

6. Niacin

Niacin is available as an over-the-counter (OTC) dietary supplement and prescription medication. It can be used to lower cholesterol, but it isn’t as effective as statins.

If you take niacin and simvastatin together, there’s a higher risk that you may develop muscle pain and damage. This is especially true if you take at least 1 gm of niacin daily. And this combination generally isn’t recommended for people of Chinese descent, since the risk of muscle damage may be higher.

Your healthcare provider can decide if taking niacin with simvastatin is safe. This includes both OTC and prescription niacin products.

7. Fibrates

Fibrates are another medication that can lower cholesterol. Examples include fenofibrate (Tricor) and gemfibrozil (Lopid). Fibrates can cause muscle pain and damage when taken on their own. When they are taken with simvastatin this risk is even higher.

It’s recommended to avoid taking gemfibrozil and simvastatin together. Despite this, you may still be able to take other fibrates with simvastatin. Your healthcare provider will weigh the potential benefits and risks of combining these medications for your specific situation.

8. Colchicine

Colchicine (Colcrys, Mitigare, Gloperba) is used for treating gout and Familial Mediterranean fever. It can interact with simvastatin, increasing the risk of muscle pain and damage. 

If you need to take colchicine, your healthcare provider may want to monitor you more closely. Let them know right away if you develop muscle pain with weakness and tea-colored urine while taking this combination.

9. Paxlovid

Paxlovid (nirmatrelvir / ritonavir) is an antiviral medication that treats COVID-19 in certain people. Since it contains ritonavir, Paxlovid can slow the breakdown of simvastatin in the body, as mentioned above.

Because of this interaction, it’s recommended to stop taking simvastatin at least 12 hours before your first Paxlovid dose. You’ll typically take Paxlovid for 5 days. You can resume simvastatin at least 5 days after your last Paxlovid dose.

If you’re prescribed Paxlovid, your healthcare team should review your current medication list before you start taking it. That way, they can help you navigate this interaction safely.

10. Grapefruit juice

You may have heard that grapefruit juice can cause problems with statins. While it’s not an issue with all statins, you should be aware of this interaction with simvastatin. That’s because this combination can increase the risk of side effects.

If grapefruit or grapefruit juice is part of your regular diet, ask your healthcare provider for guidance. They may say that a certain amount of grapefruit is OK with simvastatin. Or, they may recommend avoiding it altogether.

When should you contact your healthcare provider about simvastatin interactions?

Anytime you have questions about simvastatin interactions, you should reach out to your healthcare team. This may include your healthcare provider or pharmacist. It’s important to check with them about whether you can safely take other medications, OTC products, and supplements with simvastatin.

If you have muscle pain or feelings of weakness, let your healthcare provider know. They can determine if these symptoms are caused by an interaction with simvastatin, or by something else. If needed, they may adjust your dose or switch you to a different statin with a lower interaction risk.

Why trust our experts?

Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Our editorial standards

Meet our experts