Zocor - Safety precautions | Dosage

This article was medically reviewed by M.Pharm, Marko Tanaskovic on August 12, 2018. To read more about an author, click here.

Zocor is a drug containing simvastatin - a drug from the group of lipid lowering medications. It is classified in the group of inhibitors of HMG-CoA reductase - an enzyme responsible for the synthesis of cholesterol. Therefore, Zocor is used in patients with high blood cholesterol.

Safety precautions

Zocor is a drug from the group of statins and these drugs are known to sometimes cause muscle damage / muscle breakdown and the release of myoglobin in the blood. Increased levels of myoglobin in the blood leads to kidney damage and, consequently, its impaired function. Therefore, it is important to contact your doctor if you notice any changes in the muscles (e.g. you have sore muscles even if you didn't exercise).

Zocor can cause liver damage, which can be mild to moderate. At the beginning of therapy, the doctor will probably recommend that you do some laboratory tests to determine whether the Zocor has impaired your liver or not. If you feel pain in the upper right abdomen, you've lost appetite, or you have jaundice, you should immediately contact your doctor. If you already have liver damage or have in the past had problems with this organ, tell your doctor about it.

Caution is also required in the following situations:

  • In pregnant women or nursing mothers.
  • In patients who take danazol (a drug used to treat ovarian cysts and endometriosis). A case of fatal rhabdomyolysis in a patient who took these two drugs simultaneously has been reported.1
  • Patients who are taking some of the antifungal drugs, such as: flukonazol2, itrakonazol3 and ketoconazole4. Numerous cases of Zocor interactions with these medicines have been reported. These interactions significantly increase the risk of severe muscle damage.
  • In patients who are taking clarithromycin, azithromycin or erythromycin (antibiotics). Rhabdomyolysis has been reported during concomitant administration of Zocor with clarithromycin and azithromycin.5,6
  • In patients taking cyclosporine (immunosuppressant). Cases of rhabdomyolysis have been reported after co-administration of these two drugs.7
  • In patients treated with HIV drugs, such as: ritonavir, saquinavir, cobicistat, atazanavir and indinavir. Co-administration of these medicines with Zocor can cause serious side effects.
  • In patients with hypothyroidism.

Never combine alcohol and Zocor, as alcohol can increase its concentration in the blood which increases the risk of serious side effects.

Zocor, pregnancy and breastfeeding

Due to its potential teratogenic effects, Zocor should not be used during pregnancy. The FDA has classified this drug to the group X, which means that this drug almost certainly causes embriotoxic effects. Zocor is absolutely contraindicated during pregnancy!

Bearing in mind that Zocor may appear in breast milk and affect the lipid metabolism in infants, it is recommended to avoid breastfeeding while using this medication.


The dosage ranges from 5 to 80 mg per day, administered as an oral dose, once a day, at bedtime. It should be noted that the higher dose, the greater the risk of side effects, so the doctor should find the lowest effective dose (lowest dose that lowers cholesterol in the normal range). A dose of 80 mg should be used only in patients who have severe hypercholesterolemia.

The dose is adjusted according to the effect, so it is necessary to regularly control the level of cholesterol in the blood.


Given that the drug is metabolised by the enzyme called CYP3A4, as well as numerous other drugs, there are a number of possible interactions of Zocor with other drugs.

Significant (major) interactions (other than those listed in section Precautions) include:

  • Amlodipine, diltiazem and verapamil (the so-called calcium antagonists). Concurrent application increases the risk of liver damage and rhabdomyolysis.
  • Other drugs which are used to treat elevated levels of cholesterol and triglycerides, such as: other statins, niacin, fenofibrate, and others.
  • Amiodarone (antiarrhythmic). Co-administration leads to a large increase in the concentration of Zocor in the blood which can cause serious side effects.
  • Colchicine (medicine for gout treatment). Concomitant use leads to muscle and kidney damage.

Adverse effects

Zocor may cause the following adverse effects:

  • Muscle pain
  • Increased muscle sensitivity
  • Muscle weakness
  • Muscle cramps
  • Rhabdomyolysis
  • Inflammation of the liver
  • Inflammation of the pancreas
  • Memory impairment
  • Nightmares
  • Problems during sexual intercourse
  • Confusion
  • Allergy


  1. NCBI link 1
  2. NCBI link 2
  3. NCBI link 3
  4. NCBI link 4
  5. NCBI link 5
  6. NCBI link 6
  7. NCBI link 7

Information on this website are provided for educational purposes only and are not intended for medical advice, diagnosis or treatment.

If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.

We and our partners use technology such as cookies on our site to personalise content and ads, provide social media features, and analyse our traffic. Click below to consent to the use of this technology across the web. You can change your mind and change your consent choices at anytime by returning to this site.