• Other cholesterol-reducing drugs. Taking more than one cholesterol reducer at a time may worsen side effects, unless physicians have prescribed a specially dosed combination of medications. One fibrate called gemfibrozil is of particular concern to patients taking statins. Gemfibrozil combined with a statin may increase the patient’s risk of developing a rare, but potentially fatal side effect of rhabdomyolysis. For more information on rhabdomyolysis see Potential side effects.

  • Inotropes (e.g., digoxin). Medications that strengthen the heart’s contractions so that it can pump more blood per minute. Use with atorvastatin, fluvastatin or simvastatin may increase blood levels of inotropes, increasing the potential for side effects. 

  • Birth control pills. Use with atorvastatin may increase the blood levels of the hormones used in birth control pills, increasing the risk of side effects.

  • Calcium channel blockers. Medications that block the movement of calcium ions into heart cells and blood vessels. This increases the supply of oxygen-rich blood to the heart, lowers blood pressure and reduces the heart's workload. Use with simvastatin may increase the risk of muscle problems.

  • Protease inhibitors. Medications used in the treatment of human immunodeficiency virus (HIV). Use with simvastatin may increase the risk of developing kidney failure or muscle problems.

  • Azole antifungals (systemic antifungals). Medications used to treat serious fungal infections in the body. They may be taken orally in pill form or may be injected. Using some statins and azole antifungals in combination may increase an individual’s risk of developing muscle problems (rhabdomyolysis) that can lead to kidney failure.

  • Immunosuppressants. Medications used to reduce the body’s immune system, which are often prescribed following an organ transplant (e.g. kidney or heart transplant) to prevent the body from rejecting the donor organ. Taking statins with immunosuppressants may increase an individual’s risk of developing rhabdomyolysis.

  • Erythromycins. A type of antibiotic used in the treatment of infections. Using some statins in combination with erythromycins may increase an individual’s risk of developing rhabdomyolysis.

  • Grapefruit juice. Grapefruit juice interferes with the liver’s ability to break down (metabolize) some statins. Consequently, the medication cannot reach its intended “target.” This, in turn, can cause a toxic build-up of the statins (especially atorvastatin and simvastatin in the blood. While the buildup is less likely if the juice is ingested four or more hours prior to the medicine, patients taking statins are advised to refrain from drinking grapefruit juice. Patients may also be instructed to avoid eating grapefruit.