simvastatin, Zocor (cont.)

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Medical and Pharmacy Editor:

Large quantities of grape fruit juice (>1 quart daily) also will increase blood levels of simvastatin and should be avoided.

Amiodarone (Cordarone), verapamil (Calan Verelan, Isoptin), diltiazem, amlodipine (Norvasc), danazol (Danocrine), ranolazine (Ranexa), niacin (Niacor, Niaspan, Slo-Niacin), gemfibrozil (Lopid) and fenofibrate (Tricor) also may increase the risk of muscle toxicity when combined with simvastatin. Patients taking amiodarone, amlodipine, or ranolazine should not exceed 20 mg, and patients taking verapamil or diltiazem should not exceed 10 mg of of simvastatin daily. Patients taking gemfibrozil or danazol should not take simvastatin.

Simvastatin increases the effect of warfarin (Coumadin) and the blood concentration of digoxin (Lanoxin). Patients taking simvastatin and warfarin or digoxin should be monitored carefully.

Cholestyramine (Questran) decreases the absorption of ezetimibe (Zetia); Therefore, simvastatin should be taken 2 hours before or at least 4 hours after cholestyramine.

Chinese patients taking ≥1 g/day of niacin in combination with simvastatin 40 mg have an increased risk of muscle-related side effects. Therefore, these patients should not receive simvastatin 80 mg combined with niacin in doses ≥1 g/day. Simvastatin doses greater than 20 mg daily should be administered cautiously when combined with niacin ≥1 g/day.

PREGNANCY: Pregnant women should not use simvastatin because the developing fetus requires cholesterol for development, and simvastatin reduces the production of cholesterol. Simvastatin should only be administered to women of child bearing age if they are not likely to become pregnant.

NURSING MOTHERS: Because of the risk of adverse effects to the developing infant, simvastatin should not be administered to nursing mothers.

SIDE EFFECTS: The most common side effects of simvastatin are headache, nausea, vomiting, diarrhea, abdominal pain, muscle pain, and abnormal liver tests. Hypersensitivity reactions have also been reported.

The most serious potential side effects are liver damage and muscle inflammation or breakdown. Simvastatin shares side effects, such as liver and muscle damage associated with all statins. Serious liver damage caused by statins is rare. More often, statins cause abnormalities of liver tests. Abnormal tests usually return to normal even if a statin is continued, but if the abnormal test value is greater than three times the upper limit of normal, the statin usually is stopped. Liver tests should be measured before simvastatin is started and if there is a medical concern about liver damage thereafter.

Inflammation of the muscles caused by statins can lead to a serious breakdown of muscle cells called rhabdomyolysis. Rhabdomyolysis causes the release of muscle protein (myoglobin) into the blood. Myoglobin can cause kidney failure and even death. When used alone, statins cause rhabdomyolysis in less than one percent of patients. To prevent the development of rhabdomyolysis, patients taking simvastatin should contact their health care professional immediately if they develop unexplained muscle pain, weakness, or muscle tenderness.

Statins have been associated with increases in HbA1c and fasting serum glucose levels as are seen in diabetes.

There are also post-marketing reports of memory loss, forgetfulness, amnesia, confusion, and memory impairment. Symptoms may start one day to years after starting treatment and resolve within a median of three weeks after stopping the statin.

Reference: FDA Prescribing Information


Last Editorial Review: 5/22/2012



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