Zocor (simvastatin) is a prescription drug that’s used to treat high cholesterol and lower certain heart-related risks. Zocor can interact with other medications and supplements. For example, Zocor can interact with fibrates and niacin (Niacor).
Zocor is used to:
- treat high cholesterol in adults and some children with certain conditions
- help lower the risk of heart attack, stroke, or the need for certain heart procedures in adults with heart disease
Zocor comes as a tablet that you swallow.
An interaction can occur because one substance causes another substance to have a different effect than expected. Interactions can also occur if you have certain health conditions.
Keep reading to learn about Zocor’s possible interactions. And for more information about Zocor, including details about its uses, see this article.
Certain health conditions or other factors could raise your risk of harm if you take Zocor. In such cases, your doctor may not prescribe Zocor for you. These are known as contraindications. The list below includes Zocor’s contraindications.
If you have certain liver problems. If you have certain liver problems, your doctor likely won’t prescribe Zocor. These problems include decompensated cirrhosis and acute (sudden) liver failure. Zocor could cause liver damage, which may worsen your liver problem.
If you have these liver problems, your doctor can recommend a different treatment option for you. To learn more about Zocor’s side effects, see this article.
If you take medications that decrease the activity of certain enzymes. Zocor is broken down by a specific enzyme (protein) in your body called CYP3A4. Doctors typically will not prescribe Zocor with medications that strongly decrease the activity of this enzyme. Taking Zocor with these medications could raise the level of Zocor in your body, which could increase your risk of side effects.
Examples of these medications include:
- the antibiotic drugs erythromycin (Eryc, Ery-Tab, others) and clarithromycin
- the antifungal drugs ketoconazole and itraconazole (Sporanox)
- the protease inhibitors ritonavir (Norvir), nelfinavir (Viracept), and darunavir (Prezista)
- cobicistat (Tybost)
- nefazodone
Before taking Zocor, tell your doctor about other medications you take. They can advise you on any possible interactions with Zocor.
If you take certain medications that increase the risk of muscle problems. If you take certain medications that cause muscle problems as a side effect, your doctor likely won’t prescribe Zocor. This is because Zocor can also cause muscle problems as a side effect. Taking Zocor with these medications could further increase this risk.
Examples of these medications include:
- gemfibrozil (Lopid)
- cyclosporine (Gengraf, Neoral, Sandimmune)
- danazol
Before starting treatment with Zocor, tell your doctor about other medications you take. They can tell you about possible interactions with Zocor.
If you’ve had an allergic reaction. If you‘ve had an allergic reaction to Zocor or any of its ingredients, your doctor likely won’t prescribe Zocor. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better options for you.
Before you start taking Zocor, talk with your doctor if any of the factors above apply to you. Your doctor can determine whether Zocor is safe for you to take.
There isn’t a known interaction between Zocor and alcohol.
But keep in mind that consuming large amounts of alcohol can cause liver problems. Zocor may also cause liver problems as a side effect. Drinking while taking Zocor could further increase this risk.
If you have questions about consuming alcohol while taking Zocor, talk with your doctor or pharmacist. To learn more about Zocor’s side effects, see this article.
Before you start taking Zocor, tell your doctor and pharmacist about any prescription or over-the-counter drugs you take. Sharing this information with them may help prevent possible interactions. (To learn whether Zocor interacts with supplements, herbs, and vitamins, see the “Are there other interactions with Zocor?” section below.)
If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.
The table below lists drugs that may interact with Zocor. Keep in mind that this table does not include all drugs that may interact with Zocor. For more information about some of these interactions, see the “Drug interactions explained” section below.
| Drug group or drug name | Drug examples | What can happen |
| certain antibiotics | • erythromycin (Eryc, Ery-Tab, others)* • clarithromycin* • ciprofloxacin (Cipro) • daptomycin | can increase the risk of side effects from Zocor† |
| certain antifungals | • fluconazole (Diflucan) • ketoconazole* • itraconazole (Sporanox)* | can increase the risk of side effects from Zocor |
| certain protease inhibitors* | • ritonavir (Norvir) • nelfinavir (Viracept) • darunavir (Prezista) | can increase the risk of side effects from Zocor |
| certain antiarrhythmics | • dronedarone (Multaq) • amiodarone (Nexterone, Pacerone) | can increase the risk of side effects from Zocor |
| calcium channel blockers | • verapamil (Verelan, Verelan PM) • diltiazem (Cardizem, Tiazac, others) • amlodipine (Katerzia, Norliqva, Norvasc) | can increase the risk of side effects from Zocor |
| fibrates | • gemfibrozil (Lopid)* • fenofibrate (Antara, Tricor, Triglide) • fenofibric acid (Trilipix) | can increase the risk of side effects from Zocor and fibrates |
| niacin (Niacor) | — | can increase the risk of side effects from Zocor and niacin |
| colchicine (Colcrys, Gloperba, Mitigare) | — | can increase the risk of side effects from Zocor and colchicine |
| cyclosporine (Gengraf, Neoral, Sandimmune)* | — | can increase the risk of side effects from Zocor |
| nefazodone* | — | can increase the risk of side effects from Zocor |
| danazol* | — | can increase the risk of side effects from Zocor |
| cobicistat (Tybost)* | — | can increase the risk of side effects from Zocor |
| warfarin (Jantoven) | — | can increase the risk of side effects from warfarin |
| ranolazine (Aspruzyo Sprinkle) | — | can increase the risk of side effects from Zocor |
| digoxin (Lanoxin) | — | can increase the risk of side effects from digoxin |
| lomitapide (Juxtapid) | — | can increase the risk of side effects from Zocor |
* To learn more about this interaction, see the “When should I avoid Zocor?” section above.
† To learn more about Zocor’s side effects, see this article.
Learn more about certain drug interactions that can occur with Zocor.
Interaction with fibrates
Zocor may interact with fibrates, which are a kind of cholesterol-lowering drug.
Examples of fibrate medications include:
- gemfibrozil (Lopid)
- fenofibrate (Antara, Tricor, Triglide)
- fenofibric acid (Trilipix)
What could happen
Taking Zocor with a fibrate can increase the risk of muscle problems as a side effect of Zocor and fibrates. This is because both Zocor and fibrates can cause muscle problems when taken individually. Taking these medications together can increase this risk even more.
What you can do
Before starting Zocor treatment, tell your doctor if you take a fibrate. They can determine whether it’s safe to take these medications together.
In some cases, such as when taking gemfibrozil, your doctor may recommend a treatment other than Zocor for you. In other cases, your doctor may give you a lower dosage of Zocor than usual. Doing so can help reduce the risk of muscle problems when Zocor is taken with a fibrate.
Interaction with niacin
Zocor may interact with niacin, which is a cholesterol-lowering drug.
What could happen
Taking Zocor with high doses of niacin can increase the risk of muscle problems as a side effect of Zocor. This risk applies to niacin daily doses of at least 1,000 milligrams (mg). The risk is further increased in people who are of Chinese descent.
What you can do
Before taking Zocor, tell your doctor if you take niacin. They can determine whether it’s safe to take these medications together.
Interaction with warfarin
Zocor may interact with warfarin (Jantoven), which is a blood thinner.
What could happen
Taking Zocor with warfarin may increase the blood thinning effect of warfarin. As a result, your risk of bleeding as a side effect of warfarin may be higher when these drugs are taken together.
What you can do
Before starting Zocor treatment, tell your doctor if you take warfarin. They can recommend whether it’s safe to take these medications together. If you’re prescribed both medications, your doctor may recommend more frequent blood tests to closely monitor how well your blood is clotting while taking Zocor with warfarin.
Zocor may have other interactions. They could occur with supplements, foods, vaccines, or even lab tests. See below for details. Note that the information below does not include all other possible interactions with Zocor.
Does Zocor interact with supplements?
Before you start taking Zocor, talk with your doctor and pharmacist about any supplements, herbs, and vitamins you take. Sharing this information with them may help you avoid possible interactions.
Zocor interactions with supplements
While you’re taking Zocor, your doctor may recommend that you avoid taking red yeast rice supplements. Zocor and red yeast rice supplements work in a similar way to lower cholesterol. Taking Zocor with these supplements may increase your risk of muscle problems as a side effect.
To learn more about Zocor’s side effects, see this article.
If you have questions about interactions that may affect you, talk with your doctor or pharmacist.
Zocor interactions with herbs
Taking Zocor with an herb called St. John’s wort could make Zocor less effective than usual. (This herb is sometimes used to ease symptoms of depression and other conditions.)
St. John’s wort can cause your body to break down Zocor too quickly. As a result, taking Zocor with this supplement could lower the level of Zocor in your body. And this could make Zocor less effective.
If you take St. John’s wort, talk with your doctor before starting Zocor treatment. They can recommend whether it’s safe to continue taking this herb with Zocor.
Zocor and vitamins
There are currently no reports of Zocor interacting with vitamins. But this doesn’t mean that vitamin interactions won’t be recognized in the future.
For this reason, it’s still important to check with your doctor or pharmacist before taking any of these products while taking Zocor.
Does Zocor interact with food?
Zocor may interact with grapefruit or grapefruit juice. Consuming grapefruit products while taking Zocor may cause Zocor to build up in your body. And this could increase your risk of muscle problems as a side effect.
If you consume grapefruit products, talk with your doctor before taking Zocor. They’ll likely suggest that you limit the amount of grapefruit you consume during Zocor treatment. Doing so can help lower your risk of side effects from Zocor.
Does Zocor interact with vaccines?
There are currently no reports of Zocor interacting with vaccines. If you have questions about getting certain vaccines during your Zocor treatment, talk with your doctor.
Does Zocor interact with lab tests?
There are currently no reports of Zocor interacting with lab tests. If you have questions about getting certain lab tests while taking Zocor, talk with your doctor.
Does Zocor interact with cannabis or CBD?Cannabis (commonly called marijuana) and cannabis products, such as cannabidiol (CBD), have been specifically reported to interact with Zocor. Cannabis products could increase your risk of side effects from Zocor.
Before you start treatment with Zocor, tell your doctor and pharmacist if you use cannabis. By sharing this information with them, you may help prevent possible interactions.
Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.
Certain medical conditions or other health factors may raise the risk of interactions with Zocor. Before taking Zocor, talk with your doctor about your health history. They’ll determine whether Zocor is right for you.
Health conditions or other factors that might interact with Zocor include:
Liver problems. If you have a liver problem, talk with your doctor before taking Zocor. Zocor could cause liver damage, which may worsen your liver problem. Your doctor can tell you whether Zocor is a safe treatment option.
Your doctor likely won’t prescribe Zocor if you have decompensated cirrhosis or acute (sudden) liver failure. For details, see “When should I avoid Zocor?” above.
Being age 65 years or older. If you’re age 65 years or older, talk with your doctor before taking Zocor. Your age may increase your risk of muscle problems as a side effect of the drug. Your doctor can recommend whether Zocor is a safe treatment option for you. To learn more about Zocor’s side effects, see this article.
Kidney problems. If you have a kidney problem, such as chronic kidney disease, talk with your doctor before taking Zocor. You may have a higher risk of muscle problems as a side effect of the drug. To help lower this risk, your doctor may give you a lower dosage of Zocor than usual.
Underactive thyroid. Having an underactive thyroid that isn’t treated may increase your risk of muscle problems as a side effect of Zocor. If you have this condition, talk with your doctor before taking Zocor. They’ll likely make sure it’s treated before they prescribe Zocor for you.
Chinese ancestry. If you’re of Chinese ancestry, talk with your doctor before taking Zocor. You may have a higher risk of muscle problems as a side effect of Zocor. Your doctor can tell you whether Zocor is a safe treatment option.
Pregnancy. It may not be safe to take Zocor while pregnant. The drug may cause harm to a fetus if taken during pregnancy. If you’re pregnant or planning a pregnancy, talk with your doctor before starting Zocor treatment.
Breastfeeding. It’s recommended that you not breastfeed while taking Zocor. Statin drugs, such as Zocor, may pass into breast milk. Taking the drug while breastfeeding could cause side effects in a child who’s breastfed. If you’re breastfeeding or planning to do so, talk with your doctor before taking Zocor.
Allergic reaction. If you’ve had an allergic reaction to Zocor or any of its ingredients, your doctor will likely not prescribe Zocor. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better choices for you.
Find answers to some frequently asked questions about Zocor and possible interactions.
How do the interactions of Zocor compare with those of Lipitor?
Zocor and Lipitor are statin drugs used to treat high cholesterol and lower certain heart-related risks. These medications have similar interactions.
For example, both Zocor and Lipitor can interact with:
- certain antibiotics, such as erythromycin (Eryc, Ery-Tab, others) and clarithromycin
- certain antifungals, such as fluconazole (Diflucan) and ketoconazole
- certain other cholesterol-lowering drugs, such as fibrates and niacin (Niacor)*
But Zocor and Lipitor have some different interactions as well. For example, Zocor isn’t known to interact with birth control pills, while Lipitor might.
If you have other questions about the interactions of Zocor vs. Lipitor, talk with your doctor or pharmacist. To learn more about Lipitor’s interactions, see this article.
Is it safe to take Zocor with other cholesterol-lowering medications?
Possibly, if your doctor recommends it.
Zocor may interact with certain cholesterol-lowering drugs, such as fibrates and niacin (Niacor). (For details, see the “Drug interactions explained” section above.) But Zocor isn’t known to interact with other cholesterol-lowering drugs, such as ezetimibe (Zetia) and evolocumab (Repatha).
Zocor treats high cholesterol. Depending on your condition, your doctor may prescribe Zocor with other cholesterol-lowering drugs.
Taking certain steps can help you avoid interactions with Zocor. Before starting treatment, talk with your doctor and pharmacist. Things to discuss with them include:
- Whether you drink alcohol or use cannabis.
- Other medications you take, as well as any vitamins, supplements, and herbs. Your doctor or pharmacist can help you fill out a
medication list . - What to do if you start taking a new drug during your Zocor treatment.
It’s also important to understand Zocor’s
If you have trouble reading or understanding this information, your doctor or pharmacist can help.
Taking Zocor exactly as prescribed can also help prevent interactions.
If you still have questions about Zocor and its possible interactions, talk with your doctor.
Questions you may want to ask your doctor include:
- Does my Zocor dosage affect my risk of interactions?
- Do I have any health conditions that increase my risk of interactions with Zocor?
- What should I do if I suspect a possible drug interaction with Zocor?
To learn more about Zocor, see these articles:
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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.