Activated Ergosterol, Drisdol, D-ViSol, Ostoforte , Radiostol , Radiostol Forte , Vitamin D2
Classifications: vitamin d analog;
Therapeutic:vitamin d analog

Prototype: Calcitriol
Pregnancy Category: C


8000 IU/mL oral liquid; 50,000 units capsules, tablets; 500,000 IU/mL injection


The name vitamin D encompasses two related fat-soluble substances (sterols) that occur in nature or are synthetically prepared. Vitamin D acts like a hormone in that it is distributed through the circulation and plays a major regulatory role. Reponsible for regulation of serum calcium level.

Therapeutic Effect

Maintains normal blood calcium and phosphate ion levels by enhancing their intestinal absorption and by promoting mobilization of calcium from bone and renal tubular resorption of phosphate.


Familial hypophosphatemia (vitamin D–resistant rickets), osteomalacia (adult rickets), anticonvulsant-induced rickets and osteomalacia, osteoporosis, renal osteodystrophy, hypocalcemia associated with hypoparathyroidism; prophylaxis and treatment of nutritional rickets. Also hypophosphatemia in Fanconi's syndrome.

Unlabeled Uses

With varying clinical results in lupus vulgaris, psoriasis, and rheumatoid arthritis.


Hypersensitivity to vitamin D, hypervitaminosis D, hypercalcemia, hyperphosphatemia, renal osteodystrophy with hyperphosphatemia, malabsorption syndrome, decreased kidney function. Safe use of amounts in excess of 400 IU (10 mcg) daily during pregnancy (category C) is not established.

Cautious Use

Coronary disease; arteriosclerosis (especially in older adults); history of kidney stones; biliary tract disease; lactation.

Route & Dosage

Nutritional Rickets, Osteomalacia
Adult: PO/IM 25–125 mcg/d for 6–12 wk, may need up to 7.5 mg/d in patients with malabsorption
Child: PO/IM 50–125 mcg/d, may need up to 250–625 mcg/d in patients with malabsorption

Vitamin D–Dependent Rickets
Adult: PO/IM 250 mcg–1.5 mg/d, may need up to 12.5 mg/d (prolonged therapy with >2.5 mg/d increases risk of toxicity)
Child: PO/IM 75–125 mcg/d, may need up to 1.5 mg/d

Hypoparathyroidism, Pseudohypoparathyroidism
Adult: PO/IM 625 mcg–5 mg/d, may need up to 10 mg/d (prolonged therapy with >2.5 mg/d increases risk of toxicity)
Child: PO/IM 1.25–5 mg/d, (prolonged therapy with >2.5 mg/d increases risk of toxicity)


  • Note: 40 U = 1 mcg. Reduce dosage, once symptoms of vitamin D deficiency are relieved, to prevent hypercalcemia.
  • Give injection deeply, preferably into gluteus maximus and inject slowly. Aspirate carefully. Rotate injection sites.
  • Preserve in tightly covered, light-resistant containers. Drug decomposes when exposed to light and air.

Adverse Effects (≥1%)

Body as a Whole: Fatigue, weakness, vertigo, tinnitus, ataxia, muscle and joint pain, hypotonia (infants), exanthema, rhinorrhea; pruritus; mild acidosis. CNS: Headache, drowsiness, convulsions. GI: Metallic taste, dry mouth, anorexia, nausea, vomiting, diarrhea, constipation, abdominal cramps. Hematologic: Anemia. Musculoskeletal: Calcification of soft tissues (kidneys, blood vessels, myocardium, lungs, skin). Urogenital: Nephrotoxicity (polyuria, hyposthenuria, polydipsia, nocturia, casts, albuminuria, hematuria), kidney failure. CV: Hypertension, cardiac arrhythmias. Special Senses: Conjunctivitis (calcific); photophobia. Metabolic: Osteoporosis (adults); weight loss, chronic hypervitaminosis D in children (mental and physical retardation, suppression of linear growth).

Diagnostic Test Interference

Vitamin D may cause false increase in serum cholesterol measurements (Zlatkis-Zak reaction).


Drug: Cholestyramine, colestipol, mineral oil may decrease absorption of vitamin D.


Absorption: Readily from GI tract. Peak: After 4 wk. Duration: 2 mo or more. Distribution: Most of drug first appears in lymph, stored chiefly in liver and in skin, brain, spleen, and bones. Metabolism: In liver and kidney to active metabolites. Elimination: About 50% of PO dose in bile; may be stored in tissues for months. Half-Life: 12–24 h.

Nursing Implications

Assessment & Drug Effects

  • Monitor closely patients receiving therapeutic doses of vitamin D; must remain under close medical supervision.
  • Lab tests: When high therapeutic doses are used, progress is followed by frequent determinations (q2wk or more often) of serum calcium, phosphorus, magnesium, alkaline phosphatase, BUN, and determinations of urine calcium, casts, albumin, and RBC. Blood calcium concentration is generally kept between 9 and 10 mg/dL.
  • Monitor for hypercalcemia; in patients with osteomalacia a decrease in serum alkaline phosphatase may signal the onset of hypercalcemia.

Patient & Family Education

  • Avoid magnesium-containing antacids and laxatives with chronic kidney failure when receiving vitamin D preparations since vitamin D increases the risk of magnesium intoxication than other patients.
  • Do not use OTC medications unless approved by physician.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2023 Last Updated On: 02/01/2023 (0)
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