vitamin D (Rx, OTC)

Frequency Not Defined

Arrhythmias

Confusion

Constipation

Dry mouth

Headache

Hypercalcemia

Lethargy

Metallic taste

Muscle or bone pain

Nausea

Sluggishness

Vomiting

Contraindications

Hypercalcemia

Hypervitaminosis D

Ergocalciferol (oral): Gastrointestinal (GI), liver, or biliary disease associated with malabsorption of vitamin D analogues

Documented hypersensitivity with drugs that could have allergenic crossreactivity with ergocalceferol

Cautions

Ergocalciferol: Use with caution in renal impairment (strong caution), heart disease, kidney stones, arteriosclerosis

Obtain serum calcium twice weekly during titration

Discontinue if patient becomes hypercalcemic

Presence of tartrazine in some products may cause allergic reactions

Vitamin D toxicity may last ≥2 months after therapy is discontinued

Restrict intake in infants with idiopathic hypercalcemia

Concurrent use of cardiac glycosides

Adequate clinical response to vitamin D therapy is dependent on adequate dietary calcium

Maintain normal serum phosphorous concentrations in patients treated for hyperphosphatemia to prevent metastatic calcification

When treating hypoparathyroidism, concomitant treatment with intravenous calcium, parathyroid hormone, and/or dihydrotachysterol may also be required

Adults with a body mass index (BMI) greater than 30 kg/m² are at high risk for vitamin D deficiency due to storage of vitamin D in adipose tissue; doses higher than recommended daily allowance may be required, but must be carefully monitored to avoid toxicity

Metabolism of vitamin D may be altered in patients with chronic kidney disease

In renal impairment, supplementation with ergocalciferol may be necessary; monitor closely

In patients with rickets, the range between therapeutic and toxic doses is narrow in vitamin D–resistant patients; adjust dose based on clinical response to avoid toxicity

Pregnancy category: C (ergocalciferol)

Lactation: Drug is distributed into breast milk; use with caution

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Stimulates calcium and phosphate absorption from small intestine; stimulates phosphate resorption at renal tubule; stimulates secretion of calcium into blood from bone

Absorption

Peak effect: 1 month with daily dosing

Metabolism

Metabolized in liver

Elimination

Excretion: Urine