Vitamin D, Ergocalciferol
Brand Name: Drisdol
Generic Available
Common Dosage Forms:
Capsules: Each softgel contains Ergocalciferol, USP 1.25 mg (equivalent to 50,000 IU of vitamin D), in vegetable oil.
Drops: 200 IU of ergocalciferol/drop (8,000 IU/mL)
*Also available in lower strength OTC forms
FDA Indications/Dosages:
For the treatment of refractory rickets, also known as vitamin D resistant rickets: 12,000-500,000 IU/day
For the treatment of hypoparathyroidism: 50,000-200,000 IU/day concomitantly with calcium lactate 4 grams, six times a day.
Non-FDA Indications/Dosages:
For the treatment of vitamin D deficiency in adults (25-hydroxyvitamin D3 <20 ng/mL): 50,000 IU weekly for 8 weeks given with supplemental calcium followed by 1,000 IU daily with supplemental calcium.
Pharmacology/Pharmacokinetics: Ultraviolet light converts 7-dehydrocholesterol in the skin to cholecalciferol (vitamin D3). Both cholecalciferol and ergocalciferol (vitamin D2) are converted in the liver to 25-hydroxyvitamin D forms and then in the kidney to 1,25-dihydroxyvitamin D forms. Vitamin D (D2 or D3) is essential for the proper regulation of calcium in plasma and the activity of parathyroid hormone. Vitamin D is involved in the absorption of calcium and phosphorous from the small intestine thereby providing the necessary levels of calcium and phosphate in the plasma to promote bone mineralization. Ergocalciferol is effective in treating the hypocalcemia and hyperphosphatemia seen in hypoparathyroidism.
Drug Interactions: Mineral oil interferes with the absorption of fat-soluble vitamins, including vitamin D. Addition of thiazide diuretics to hypoparathyroid patients concurrently taking ergocalciferol may cause hypercalcemia.
Contraindications/Precautions: Contraindicated in patients with hypercalcemia, malabsorption syndrome, and hypervitaminosis D. Idiopathic hypercalcemia may be caused by hypersensitivity to vitamin D. In these cases, vitamin D must be strictly restricted. The range between therapeutic and toxic doses is narrow. Dosage levels must be individualized to prevent toxic effects. Frequent blood calcium levels should be taken. Adequate dietary calcium is necessary for clinical response to vitamin D therapy.
Adverse Effects: The range between therapeutic and toxic doses is narrow. Toxicity may result in impairment of renal function, mental retardation, bone demineralization, calcification of the soft tissues, nausea, anorexia, constipation, anemia, and weight loss.
Patient Consultation: May be taken without regard to meals. Closely follow prescribed calcium supplementation. Do not exceed prescribed dosage. Contact a physician if the above side effects are severe or persistent. Store in a cool, dry place away from light and children. If a dose is missed, skip it and return to dosing schedule.
