Simvastatin

Brand names

• Zocor

Usage

To treat high cholesterol. Also used to reduce the risk of stroke or transient ischemic attack ("mini-stroke") in patients with high cholesterol and coronary artery disease. Usually prescribed after first lines of treatment-including diet, weight loss, and exercise-fail to reduce total and low-density lipoprotein (LDL) cholesterol to acceptable levels.

How it works

Simvastatin blocks the action of an enzyme required for the manufacture of cholesterol. thereby interfering with its formation. By lowering the amount of cholesterol in the liver cells, simvastatin increases the formation of receptors for LDL, and thereby reduces blood levels of total and LDL cholesterol. In addition to lowering LDL cholesterol, simvastatin also modestly reduces triglyceride levels and raises HDL (the so-called good) cholesterol.

Side effects

Serious

Fever, unusual or unexplained muscle aches and tenderness. Get medical help right away.

Common

Side effects occur in only 1 % to 2% of patients. They may include constipation or diarrhea, dizziness or lightheadedness, bloating or gas, heartburn, nausea, skin rash, stomach pain, rise in liver enzymes.

Less common

Insomnia.

Possible interactions

Other medicaments:

Simvastatin may increase the effects of:

• digoxin (Lanoxin).
• warfarin (Coumadin); more frequent testing of INR (prothrombin time or protime) will be needed.

Simvastatin taken concurrently with:



• amprenavir (Agenerase) and ritonavir (Norvir) and perhaps other protease inhibitors may increase simvastatin levels and the risk of muscle damage (myopathy).
• clarithromycin (Biaxin) may increase risk of muscle damage.
• clofibrate (Atromid-S) or other fibrates may result in increased risk of serious muscle toxicity.
• cyclosporine (Sandimmune) can result in kidney failure and myopathy.
• erythromycin (various) may increase risk of muscle damage.
• gemfibrozil (Lopid) may alter absorption and excretion of simvastatin and may also increase risk of muscle damage (rhabdomyolysis).
• itraconazole (Sporanox) or ketoconazole (Nizoral) may increase risk of muscle damage.
• nefazodone (Serzone) may increase risk of muscle damage.
• niacin may cause an increased frequency of muscle problems (myopathy) when combined with a related medicine (lovastatin)-caution is advised. Niacin may also increase homocysteine levels-a known risk factor for heart disease.
• quinupristin/dalfopristin (Synercid) may increase the risk for myopathy by increasing simvastatin blood levels.
• verapamil (Verelan) may increase risk of muscle damage.

The following medicament may decrease the effects of simvastatin:



• cholestyramine (Questran) may reduce absorption of simvastatin; take simvastatin 1 hour before or 4 hours after cholestyramine.
• fosphenytoin (Cerebyx) or phenytoin (Dilantin) may increase the body chemicals (enzymes) that remove simvastatin and blunt simvastatin benefits. Careful patient monitoring and dose increases may be needed.

Herbal medicines or minerals:

Garlic may inhibit blood-clotting (platelet) aggregation-something to consider if you are already taking a platelet inhibitor. The FDA has allowed one dietary supplement called Cholestin to continue to be sold. This preparation actually contains lovastatin. Since use of two HMG-CoA inhibitors may increase risk of rhabdomyolysis or myopathy, the combination is not advised. Because St. John's wort and this medicine can increase sun sensitivity, the combination is not advised.
Using plant stanol ester products (Benecol) with this medicine can help further lower total and LDL cholesterol. Soy products (milk, tofu, etc.) contain phytoestrogens that have led to an FDA-approved health claim for reducing risk of heart disease (if they have at least 6.25 grams of soy protein per serving). Substituting soy for some of the meat in your diet can also help further lower cholesterol. Because this medicine can deplete co-enzyme Q10, supplementation may be needed.

Beverages:

Do not take this medicine with grapefruit juice. Blood levels will be markedly increased, increasing risk of muscle damage. May be taken with milk or water.

Discontinuation:

Do not stop this medicament without your physician's knowledge and guidance. There may be a significant increase in blood cholesterol levels following discontinuation of this medicament.