Interactions

Possible interactions include:

• Aluminum. Taking vitamin D and phosphate binders that have aluminum might cause harmful levels of aluminum in people with kidney failure. Phosphate binders treat high blood levels of phosphate in people with longtime kidney disease.
• Anticonvulsants. The anticonvulsant medicines phenobarbital (Sezaby) and phenytoin (Dilantin, Phenytek) break down more vitamin D. This lessens how well the body can take in calcium.
• Atorvastatin (Lipitor). Taking vitamin D may affect the way the body uses this cholesterol medicine.
• Calcipotriene (Dovonex, Sorilux). Don't take vitamin D with this psoriasis medicine. Mixing the two might raise the risk of having too much calcium in the blood, called hypercalcemia.
• Cholestyramine (Prevalite, Locholest). Taking vitamin D with this cholesterol-lowering medicine can lower how much vitamin D the body takes in.
• Cytochrome P450 3A4 substrates, also called CYP3A4 substrates. Use vitamin D with care if you take a medicine affected by these enzymes. One such medicine is the cholesterol-lowering medicine lovastatin (Altoprev).
• Digoxin (Lanoxin). Don't take high doses of vitamin D with this heart medicine. High doses of vitamin D can cause too much calcium in the blood, called hypercalcemia. Hypercalcemia raises the risk of fatal heart conditions with digoxin.
• Diltiazem (Cardizem, Tiazac, others). Don't take high doses of vitamin D with this blood pressure medicine. High doses of vitamin D can cause too much calcium in the blood, called hypercalcemia. Hypercalcemia may keep the medicine from working as it should.
• Orlistat (Xenical, Alli). Taking this weight-loss medicine can lower how much vitamin D the body takes in.
• Thiazide diuretics. Taking these blood pressure medicines with vitamin D raises the risk of too much calcium in the blood, called hypercalcemia.
• Steroids. Taking steroid medicines such as prednisone can keep the body from taking in calcium and affect how the body uses vitamin D.
• Stimulant laxatives. Long-term use of high doses of stimulant laxatives can lessen how much vitamin D and calcium the body takes in.
• Verapamil (Verelan). Taking high doses of vitamin D with this blood pressure medicine can cause too much calcium in the blood, called hypercalcemia. High doses of vitamin D also might keep verapamil from working as well.