Doctors prescribe Vytorin to treat high cholesterol. Vytorin contains two active ingredients – simvastatin and ezetimibe. Simvastatin lowers cholesterol by decreasing the production of cholesterol in the liver. Ezetimibe works differently. It acts inside the intestines to block the cholesterol in food from being absorbed.

A relatively common side effect of simvastatin and other statin drugs is muscle pain and sometimes muscle damage. Coenzyme Q10, also called CoQ10, has been promoted as a supplement that might help prevent this side effect.

Our bodies produce coenzyme Q10 naturally. It exists in every active human cell and is essential for cells to work. It also acts as an antioxidant.

Some people have lower blood levels of CoQ10, but scientists aren't sure what this means or if something needs to be done to correct it.

Here’s the biological rationale for why this chemical could potentially help prevent statin-induced muscle pain and damage. Studies show that taking a statin can sometimes decrease the amount of CoQ10 in muscle. In addition, people with high cholesterol levels tend to have lower than usual CoQ10 blood levels.

However, it's not clear that the lower CoQ10 is the cause of statin-induced muscle pain or weakness. Even if lower CoQ10 is the cause, extra CoQ10 taken orally might be broken down in the intestine before reaching the blood stream. Then it still needs to get from the blood into muscle cells.

Also, the "correct" dose of CoQ10 is unknown. Studies have used doses ranging from 50 milligrams per day to 1,200 milligrams per day. The more usual doses are 100 to 600 milligrams per day, in divided doses.

Coenzyme Q10 seems to be well-tolerated and have minimal side effects. Some people experience stomach discomfort, nausea or vomiting. Rare side effects include rash or itching. Other side effects may include dizziness, difficulty sleeping, irritability, headache, sensitivity to light, fatigue or flulike symptoms.

In theory, coenzyme Q10 may increase the risk of blood clots or increase the risk of bleeding. (In some people, based on one report, coenzyme Q10 affected components of the blood involved with forming clots.) If you have a blood clotting disorder or a history of blood clots, or if you use anticoagulants (blood thinners) or antiplatelet drugs such as warfarin (Coumadin), heparin or clopidogrel (Plavix), speak with your doctor before using coenzyme Q10.