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Ergocalciferol

Class: Vitamin D
ATC Class: A11CC01
VA Class: VT504
CAS Number: 50-14-6
Brands: Drisdol

Medically reviewed by Drugs.com on Feb 1, 2021. Written by ASHP.

Introduction

A vitamin D analog.

Uses for Ergocalciferol

Hypoparathyroidism and Pseudohypoparathyroidism

Management of hypocalcemia and its clinical manifestations in patients with postsurgical or idiopathic hypoparathyroidism and pseudohypoparathyroidism.

Familial Hypophosphatemia

Treatment of familial hypophosphatemia (vitamin D-resistant rickets).

Because the large doses of ergocalciferol needed in this disorder often cause toxicity and persistent hypercalcemia, some clinicians prefer dihydrotachysterol (no longer commercially available in US) or calcitriol and phosphate supplements.

Familial Hypophosphatemia associated with Fanconi Syndrome

Has been used with treatment of acidosis, to manage hypophosphatemia associated with Fanconi syndrome.

Nutritional Rickets or Osteomalacia

Has been used in the treatment of nutritional rickets or osteomalacia.

Also has been used in the management of tetany and rickets in vitamin D-deficient infants.

Anticonvulsant-induced Rickets and Osteomalacia

Has been used in the treatment of rickets or osteomalacia secondary to long-term high-dose anticonvulsant therapy.

May be used in the prevention of anticonvulsant-induced rickets and osteomalacia (particularly in those receiving 2 or more anticonvulsants and who have inadequate nutrition and exposure to UV light such as institutional patients). Adequate vitamin D supplementation usually prevents associated osteomalacia.

Vitamin D-dependent Rickets

Has been used in the treatment of vitamin D-dependent rickets.

Osteoporosis

Has been used in conjunction with calcium in the prevention and treatment of osteoporosis.

In addition to lifestyle modifications (e.g., regular weight-bearing exercise, avoidance of excessive alcohol and tobacco use), the National Osteoporosis Foundation recommends a daily intake of 800–1000 units of vitamin D for adults ≥50 years of age; other experts recommend higher amounts.

Glucocorticoid-induced Osteoporosis

Has been used for prevention of glucocorticoid-induced osteoporosis.

The American College of Rheumatology (ACR) recommends optimizing dietary intake of calcium (1–1.2 g daily) and vitamin D (600–800 units daily) in all patients receiving long-term glucocorticoid therapy (defined as a daily dosage equivalent to 2.5 mg of prednisone or higher for ≥3 months).

Because of concerns about potential harms (e.g., cardiovascular risks), ACR states that additional study is needed to determine potential benefits versus risks of calcium and vitamin D supplementation in patients receiving glucocorticoids.

Dietary and Replacement Requirements

Adequate intake (AI) (minimum daily intake) of vitamin D is needed to support calcium metabolism and bone health, particularly in the young and old, and thus prevent rickets in children and osteomalacia in adults.

In addition, AI of vitamin D prevents secondary hyperparathyroidism and associated abnormalities in calcium metabolism that can result in porotic bone changes.

Ergocalciferol Dosage and Administration

General

  • In patients with familial hypophosphatemia (vitamin D-resistant rickets) or hypoparathyroidism, measure serum calcium and phosphorus every 2 weeks or more frequently as needed. In these patients, the manufacturers recommend radiographic examination of the bones every month until the condition stabilizes and is corrected; however, some clinicians believe this is unnecessary.

  • Adequate dietary calcium is necessary for clinical response to vitamin D therapy.

Administration

Usually administered orally once daily.

Has been administered IM in some patients (e.g., those with GI, liver, or biliary disease associated with malabsorption of vitamin D analogs); however, ergocalciferol injection is no longer commercially available in the US.

Oral Administration

To administer the oral solution, use the oral syringe provided by the manufacturer to measure the dose and administer the solution directly into the patient's mouth.

Dosage

Activity of ergocalciferol may be expressed in terms of USP or International Units (IU, units) which are equivalent; 1 unit of vitamin D equals the biologic activity of 25 ng.

Each mg of ergocalciferol is equivalent to 40,000 USP units; each mcg of the drug is equivalent to 40 USP units.

Dosage expressed by weight (mg, mcg) or units.

Dosage depends on nature and severity of hypocalcemia. Individualize dosage to maintain serum calcium concentrations of 9–10 mg/dL.

Pediatric Patients

Hypoparathyroidism and Pseudohypoparathyroidism†
Oral

1.25–5 mg daily with calcium supplements.

Prolonged administration of dosages >2.5 mg daily may increase risk of toxicity; gradually decrease dosage as serum calcium concentrations approach normal.

Familial Hypophosphatemia (Vitamin D-Resistant Rickets)
Oral

Initially, 1–2 mg daily with phosphate supplements.

May increase daily dosage in 250- to 500-mcg increments at 3- to 4-month intervals until an adequate response is obtained.

After growth is complete, may reduce dosage.

Familial Hypophosphatemia Associated with Fanconi Syndrome†
Oral

625 mcg to 1.25 mg daily have been used.

Nutritional Rickets† and Osteomalacia†
Normal GI Absorption
Oral

25 mcg daily has been used and resulted in normal serum calcium and phosphate concentrations in about 10 days, radiographic evidence of bone healing within 2–4 weeks, and complete healing within 6 months.

50–125 mcg daily has been used for 6–12 weeks for more prompt healing.

May discontinue drug if healing has occurred with therapy and correction of diet.

Malabsorption
Oral

Children: 250–625 mcg daily.

A single 7.5- to 15-mg dose (in oil solution) has been given when compliance was not predictable.

Infants with tetany and rickets: Initially administer calcium to control tetany then 50–125 mcg daily (until bones have healed) or 250 mcg daily for about 3 weeks.

Vitamin D-Dependent Rickets†
Oral

75–125 mcg daily; some may require up to 1.5 mg daily.

Dietary and Replacement Requirements

AAP recommends a minimum intake of 400 units daily in all infants, children, and adolescents.

Breast-fed or partially breast-fed infants: AAP recommended supplemental dosage is 400 units daily; start in the first few days of life. Continue until the child is weaned and consumes ≥1 L or quart of vitamin D-fortified formula or milk daily.

Infants and older children who consume <1 L of vitamin D-fortified formula or milk daily: AAP recommends supplemental dosage of 400 units daily.

Adolescents who do not consume 400 units of vitamin D daily from vitamin D-fortified milk or foods: AAP recommends supplemental dosage of 400 units daily.

Children at increased risk for vitamin D deficiency (e.g., those with fat malabsorption, those receiving anticonvulsant therapy): Higher dosages may be needed.

Dietary reference intake values for vitamin D currently recommended by the National Academy of Sciences (NAS) are as follows:

Infants <1 year of age: AI of 400 units (10 mcg) daily. (Because of insufficient data to establish recommended dietary allowances [RDAs] in infants <1 year of age, adequate intake [AI] is used in this age group. )

Children and adolescents 1–18 years of age: RDA of 600 units (15 mcg) daily assuming minimal sun exposure.

Adults

Hypoparathyroidism and Pseudohypoparathyroidism†
Oral

625 mcg to 5 mg (up to 10 mg) daily with calcium supplements and/or IM or IV PTH.

Prolonged administration of dosages >2.5 mg daily may increase risk of toxicity; gradually decrease dosage as serum calcium concentrations approach normal.

Familial Hypophosphatemia (Vitamin D-Resistant Rickets)
Oral

250 mcg to 1.5 mg (up to 12.5 mg) daily with phosphate supplements (usually 1–2 g of elemental phosphorus daily) to maintain serum phosphorus concentrations of at least 3 mg/dL.

Familial Hypophosphatemia Associated with Fanconi Syndrome†
Oral

1.25–5 mg (up to 10 mg) daily have been used along with treatment for acidosis.

Nutritional Rickets† and Osteomalacia†
Normal GI absorption
Oral

25 mcg daily has been used resulting in normal serum calcium and phosphorus concentrations in about 10 days, radiographic evidence of bone healing within 2–4 weeks, and complete healing within 6 months.

50–125 mcg daily has been used for 6–12 weeks for more prompt healing.

May discontinue drug if healing has occurred with therapy and correction of diet.

Severe Malabsorption
Oral

250 mcg to 7.5 mg. (See Contraindications under Cautions.)

Anticonvulsant-Induced Rickets and Osteomalacia†
Oral

50 mcg to 1.25 mg daily.

25 mcg daily or 250 mcg weekly has been used for prevention in those receiving long-term anticonvulsant therapy.

Vitamin D-Dependent Rickets†
Oral

250 mcg to 1.5 mg daily; some may require up to 12.5 mg daily.

Prolonged administration of dosages >2.5 mg daily may result in toxicity.

Osteoporosis†
Oral

25–250 mcg daily or 1.25 mg 2 times weekly has been used with calcium and fluoride supplements.

Dietary and Replacement Requirements

Dietary reference intake values for vitamin D currently recommended by NAS are as follows:

Adults 19–50 years of age: RDA of 600 units (15 mcg) daily assuming minimal sun exposure.

Adults 51–70 years of age: RDA of 600 units (15 mcg) daily assuming minimal sun exposure.

Adults >70 years of age: RDA of 800 units (20 mcg) daily assuming minimal sun exposure.

Prescribing Limits

Pediatric Patients

Infants and children
Oral

Chronic daily ingestion of 25 mcg daily may result in hypervitaminosis D.

Adults

Oral

Chronic daily ingestion of 1.25–2.5 mg daily may result in hypervitaminosis D.

Cautions for Ergocalciferol

Contraindications

  • Hypercalcemia.

  • Known abnormal sensitivity to toxic effects of vitamin D and hypervitaminosis D.

  • Hypervitaminosis D.

  • Manufacturers state oral ergocalciferol is contraindicated in patients with malabsorption syndrome.

Warnings/Precautions

Warnings

Concomitant Diseases

Administer with extreme caution, if at all, to patients with impaired renal function and with extreme caution in patients with heart disease, renal stones, or arteriosclerosis.

Hypercalcemia

Acute or chronic administration of excessive doses of vitamin D analogs or enhanced responsiveness to physiologic amounts of ergocalciferol or cholecalciferol may lead to hypervitaminosis D manifested by hypercalcemia.

Hypersensitivity to vitamin D may be one etiologic factor in infants with idiopathic hypercalcemia. Restrict use of vitamin D in these cases.

Acute hypercalcemia may increase risk of cardiac arrhythmias and seizures, and result in cardiac arrhythmias in presence of cardiac glycosides.

Sensitivity Reactions

Tartrazine Sensitivity

Drisdol capsules contain tartrazine (FD&C yellow No. 5), which may cause allergic-type reactions including bronchial asthma in susceptible individuals. Incidence of tartrazine sensitivity is low, but it frequently occurs in patients who are sensitive to aspirin.

General Precautions

Hyperphosphatemia

In patients with hyperphosphatemia (e.g., those with renal osteodystrophy), use a phosphate binder and a low-phosphate diet to control serum phosphorus concentrations to prevent metastatic calcification.

Specific Populations

Pregnancy

Category C.

Lactation

Distributed into milk. Caution if used in nursing women. Do not administer large doses of vitamin D analogs.

Pediatric Use

Individualize pediatric doses.

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults; however, other experience indicates no substantial differences in safety and efficacy relative to younger adults.

Select dosage with caution because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.

Renal Impairment

Administer with caution, if at all, to patients with impaired renal function.

Common Adverse Effects

Possible hypervitaminosis D effects: polyuria, nocturia, polydipsia, hypercalciuria, reversible azotemia, hypertension, nephrocalcinosis, generalized vascular calcification, irreversible renal insufficiency (may be fatal), mental retardation, widespread soft tissue calcification, osteoporosis, dwarfism, vague aches, stiffness, weakness, nausea, anorexia, constipation, mild acidosis, anemia, weight loss.

Interactions for Ergocalciferol

Specific Drugs

Drug

Interaction

Comments

Cardiac glycosides

Concurrent use of vitamin D analogs and cardiac glycosides may result in cardiac arrhythmias

Use concomitantly with caution

Cholestyramine

Intestinal absorption of the vitamin D analog may be decreased

Allow as long a time interval as possible between ingestion of ergocalciferol and cholestyramine

Colestipol

Intestinal absorption of the vitamin D analog may be decreased

Allow as long a time interval as possible between ingestion of the vitamin D analog and colestipol

Corticosteroids

Corticosteroids may counteract effects of vitamin D analogs

Mineral oil

Interferes with absorption of vitamin D preparations

Thiazide diuretics

Risk of hypercalcemia (may be transient and self-limited)

May require discontinuance of the vitamin D analog

Phenobarbital

Plasma concentrations of 25-hydroxylated ergocalciferol may be decreased

Phenytoin

Plasma concentrations of 25-hydroxylated ergocalciferol may be decreased

Orlistat

Potential interaction with drugs affecting lipid absorption (e.g., orlistat), resulting in decreased absorption of the oral vitamin D analog

Allow at least 2 hours between ingestion of the vitamin D analog and orlistat

Ergocalciferol Pharmacokinetics

Absorption

Bioavailability

Readily absorbed (about 80%) from GI tract (mainly in the small intestine); presence of bile required.

Onset

Hypercalcemic action: 10–24 hours.

Maximal hypercalcemic effects occur about 4 weeks after daily administration of a fixed dose.

Duration

Hypercalcemic action: ≥2 months.

Special Populations

Extent of GI absorption may be decreased in patients with hepatic, biliary, or GI disease (e.g., Crohn’s disease, Whipple’s disease, sprue).

Not known whether aging alters GI absorption of physiologic amounts of vitamin D; however, limited data indicate that absorption may be decreased in geriatric patients.

Distribution

Extent

Enters blood via chylomicrons of lymph and then associates mainly with a specific α-globulin (vitamin D-binding protein).

25-Hydroxyergocalciferol (metabolite) may be distributed into milk after administration of large doses.

Elimination

Metabolism

In the liver, metabolized to 25-hydroxy derivatives by vitamin D 25-hydroxylase enzyme; hepatic microsomal enzymes may be involved in degrading ergocalciferol metabolites. Further metabolized in kidneys to 1,25-dihydroxyvitamin D.

Stability

Storage

Oral

Capsules and Solution

Tight, light resistant containers at 20–25°C (may be exposed to 15–30°C).

Actions

  • A vitamin D analog.

  • Ergocalciferol increases intestinal absorption of calcium and phosphate and elevates serum calcium and phosphate concentrations sufficiently to permit bone mineralization.

  • Also promotes calcium reabsorption by the kidneys; importance of this effect is not known.

  • Activated form of ergocalciferol may have a negative feedback effect on PTH production.

Advice to Patients

  • Importance of diet and calcium supplementation regimen adherence to achieve a clinical response to vitamin D therapy.

  • Importance of immediate reporting of potential manifestations of hypercalcemia.

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

  • Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Ergocalciferol

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Bulk

Powder*

Oral

Capsules, liquid-filled

1.25 mg (50,000 units)*

Drisdol

Validus

Ergocalciferol Capsules

Solution

200 mcg (8000 units) per mL*

Ergocalciferol Oral Solution

Ergocalciferol is also commercially available in combination with other vitamins and minerals, analgesic-antipyretics, amino acids, infant formulas, laxatives, and protein supplements.

AHFS DI Essentials™. © Copyright 2022, Selected Revisions February 11, 2019. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.

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