Before Using This Dietary Supplement

If you are taking this dietary supplement without a prescription, carefully read and follow any precautions on the label. For vitamin D and related compounds, the following should be considered:

Allergies—Tell your health care professional if you have ever had any unusual or allergic reaction to alfacalcidol, calcifediol, calcitriol, dihydrotachysterol, doxercalciferol, ergocalciferol, or paricalcitol. Also, tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—It is especially important that you are receiving enough vitamin D when you become pregnant and that you continue to receive the right amounts of vitamins throughout your pregnancy. The healthy growth and development of the fetus depend on a steady supply of nutrients from the mother.

You may need vitamin D supplements if you are a strict vegetarian (vegan-vegetarian) and/or have little exposure to sunlight and do not drink vitamin D-fortified milk.

Taking too much alfacalcidol, calcifediol, calcitriol, dihydrotachysterol, or ergocalciferol can also be harmful to the fetus. Taking more than your health care professional has recommended can cause your baby to be more sensitive than usual to its effects, can cause problems with a gland called the parathyroid, and can cause a defect in the baby's heart.

Doxercalciferol or paricalcitol have not been studied in pregnant women. However, studies in animals have shown that paricalcitol causes problems in newborns. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is especially important that you receive the right amounts of vitamins so that your baby will also get the vitamins needed to grow properly. Infants who are totally breast-fed and have little exposure to the sun may require vitamin D supplementation. However, taking large amounts of a dietary supplement while breast-feeding may be harmful to the mother and/or baby and should be avoided.

Only small amounts of alfacalcidol, calcifediol, calcitriol, or dihydrotachysterol pass into breast milk and these amounts have not been reported to cause problems in nursing babies.

It is not known whether doxercalciferol or paricalcitol passes into breast milk. Be sure you have discussed the risks and benefits of the supplement with your doctor.

Children—Problems in children have not been reported with intake of normal daily recommended amounts. Some studies have shown that infants who are totally breast-fed, especially with dark-skinned mothers, and have little exposure to sunlight may be at risk of vitamin D deficiency. Your health care professional may prescribe a vitamin/mineral supplement that contains vitamin D. Some infants may be sensitive to even small amounts of alfacalcidol, calcifediol, calcitriol, dihydrotachysterol, or ergocalciferol. Also, children may show slowed growth when receiving large doses of alfacalcidol, calcifediol, calcitriol, dihydrotachysterol, or ergocalciferol for a long time.

Studies on doxercalciferol or paricalcitol have been done only in adult patients, and there is no specific information comparing the use of doxercalciferol or paricalcitol in children with use in other age groups.

Older adults—Problems in older adults have not been reported with intake of normal daily recommended amounts. Studies have shown that older adults may have lower blood levels of vitamin D than younger adults, especially those who have little exposure to sunlight. Your health care professional may recommend that you take a vitamin supplement that contains vitamin D.

Medicines or other dietary supplements—Although certain medicines or dietary supplements should not be used together at all, in other cases they may be used together even if an interaction might occur. In these cases, your health care professional may want to change the dose, or other precautions may be necessary. When you are taking vitamin D and related compounds, it is especially important that your health care professional know if you are taking any of the following:

• Antacids containing magnesium—Use of these products with any vitamin D-related compound may result in high blood levels of magnesium, especially in patients with kidney disease

• Calcium-containing preparations or
• Thiazide diuretics (water pills)—Use of these preparations with vitamin D may cause high blood levels of calcium and increase the chance of side effects

• Vitamin D and related compounds, other—Use of vitamin D with a related compound may cause high blood levels of vitamin D and increase the chance of side effects.

Other medical problems—The presence of other medical problems may affect the use of vitamin D and related compounds. Make sure you tell your health care professional if you have any other medical problems, especially:

• Heart or blood vessel disease—Alfacalcidol, calcifediol, calcitriol, or dihydrotachysterol may cause hypercalcemia (high blood levels of calcium), which may make these conditions worse

• Kidney disease—High blood levels of alfacalcidol, calcifediol, calcitriol, dihydrotachysterol, or ergocalciferol may result, which may increase the chance of side effects

• Sarcoidosis—May increase sensitivity to alfacalcidol, calcifediol, calcitriol, dihydrotachysterol, or ergocalciferol and increase the chance of side effects