What is the drug Drisdol used for?

October 7, 2025 •

3 min read

Drisdol is a high-potency, prescription-only form of vitamin D2, which is also known by its generic name, ergocalciferol. It functions as a synthetic calcium regulator for oral administration and helps the body absorb calcium and phosphorus effectively. This medication is not for general vitamin D supplementation and is typically reserved for treating specific, diagnosed medical conditions.

Quick Summary

Drisdol is a high-potency vitamin D2 medication (ergocalciferol) prescribed for specific conditions involving poor calcium and phosphate regulation. Its key uses include treating hypoparathyroidism, refractory rickets, and familial hypophosphatemia.

Key Points

Prescription Vitamin D2: Drisdol is the brand name for ergocalciferol, a prescription-strength form of vitamin D2, used for treating severe deficiencies and metabolic disorders.
Treats Specific Conditions: It is prescribed for hypoparathyroidism, refractory rickets, and familial hypophosphatemia, not for routine supplementation.
Promotes Calcium and Phosphate Absorption: By promoting mineral absorption from the gut, Drisdol helps maintain proper calcium and phosphorus levels necessary for bone health.
Risk of Overdose: A major concern is hypervitaminosis D, or vitamin D overdose, which can cause hypercalcemia and damage vital organs like the kidneys.
Requires Close Medical Monitoring: Due to the nature of the drug, administration must be individualized under strict medical supervision with frequent blood tests.
Considered Less Potent than D3: For general vitamin D level maintenance, vitamin D3 (cholecalciferol) is often preferred as it is more effective at raising and sustaining blood levels.
Interacts with Other Medications: Drisdol's absorption can be affected by other medications and supplements, necessitating careful scheduling and consultation.

What is Drisdol (Ergocalciferol)?

Drisdol is the brand name for ergocalciferol, a prescription drug that is a synthetic form of vitamin D2. This fat-soluble vitamin is essential for maintaining proper calcium and phosphorus levels by promoting their absorption from the intestines, which is vital for strong bones and teeth. Unlike over-the-counter supplements, Drisdol is a potent, high-dose medication used under medical supervision for specific disorders not responsive to standard supplementation.

Primary Medical Uses of Drisdol

Drisdol is primarily prescribed for medical conditions caused by or resulting in severe vitamin D deficiency and impaired mineral metabolism.

Treating Hypoparathyroidism

Hypoparathyroidism is a condition where low levels of parathyroid hormone lead to decreased blood calcium. Drisdol helps increase and regulate serum calcium and phosphate by promoting intestinal absorption, often used alongside calcium supplements. The administration of Drisdol requires careful medical supervision to prevent potential adverse effects.

Managing Rickets and Osteomalacia

Rickets in children and osteomalacia in adults involve weakened bones due to severe vitamin D deficiency. Drisdol is used for refractory rickets, which doesn't improve with standard vitamin D treatment. It can also be used for nutritional rickets requiring increased amounts, with treatment potentially lasting months.

Addressing Familial Hypophosphatemia

This inherited condition causes low blood phosphate, leading to rickets or osteomalacia. Drisdol is part of the treatment plan as vitamin D metabolites increase phosphate reabsorption in the kidneys. Therapy requires careful monitoring with regular blood tests.

Treatment for other deficiency-related issues

Less commonly, Drisdol may be used for malabsorption disorders or in patients with chronic kidney disease to address vitamin D deficiency and related bone issues.

Drisdol vs. Vitamin D3 (Cholecalciferol)

Drisdol (ergocalciferol, vitamin D2) differs from cholecalciferol (vitamin D3), the form the body produces from sunlight. While both are vitamin D forms, D3 is generally considered more effective at raising and maintaining blood vitamin D levels due to a longer half-life. High-dose Drisdol is prescription-only for specific conditions, while D3 is widely available over-the-counter for general supplementation.


Feature	Drisdol (Ergocalciferol, Vitamin D2)	Cholecalciferol (Vitamin D3)
Source	Produced by plants and yeast (synthetic).	Produced by the body from sunlight; also from animal products and supplements.
Potency	Considered less effective at raising and maintaining active vitamin D levels in the body.	Considered more effective at raising and sustaining blood vitamin D levels.
Duration	Has a shorter half-life in the body compared to D3.	Has a longer half-life, making it stay in the body longer.
Prescription Status	High-dose formulations are available by prescription only.	Available over-the-counter and in prescription formulations.
Common Use	Prescribed for specific and severe deficiencies or metabolic disorders.	More commonly used for general nutritional supplementation.

Administration

Drisdol administration is highly individualized and determined by a healthcare provider based on the patient's condition and mineral levels. Following prescription instructions is critical. It is best absorbed with a fat-containing meal. Regular blood tests are needed to monitor calcium and phosphate levels due to potential risks. Calcium supplements and specific dietary instructions may also be necessary.

Potential Side Effects and Precautions

The main risk with Drisdol is hypervitaminosis D, leading to hypercalcemia (high blood calcium).

Symptoms of hypervitaminosis D and hypercalcemia include:

Nausea, vomiting, appetite loss, constipation.
Increased thirst and urination.
Muscle weakness, aches, stiffness.
Fatigue, confusion.
Severe cases can cause kidney impairment and irregular heartbeats.

Precautions:

Drisdol should not be used by patients with existing high calcium levels or malabsorption issues.
It can interact with medications like mineral oil and certain diuretics.
Increased amounts are risky during pregnancy and breastfeeding; use only under medical guidance.
Some capsules contain tartrazine, which may cause allergic reactions.

Conclusion

Drisdol is a potent, prescription medication for severe vitamin D-related deficiencies and metabolic disorders. It is not for general use and requires careful diagnosis, individualized administration, and strict medical monitoring to avoid serious side effects like hypervitaminosis D. Patients must follow their doctor's instructions precisely for administration, diet, and other medications to ensure safe and effective treatment. While Drisdol is effective for targeted conditions, D3 is often preferred for general supplementation. Consult a healthcare provider for appropriate treatment.

MedlinePlus: Ergocalciferol Information

Frequently Asked Questions

Drisdol is a high-potency, prescription-only formulation of vitamin D2 (ergocalciferol) used to treat specific medical disorders. Standard over-the-counter supplements, which may contain D2 or D3, have much lower amounts and are intended for general nutritional support.

In hypoparathyroidism, the body doesn't produce enough parathyroid hormone to regulate calcium. Drisdol helps by increasing the absorption of calcium from the diet, thereby raising blood calcium levels.

While Drisdol contains vitamin D, it is generally reserved for treating severe deficiencies and specific metabolic disorders. For most cases of deficiency, a lower-amount, over-the-counter supplement, often vitamin D3, is more appropriate.

Signs of a Drisdol overdose (hypervitaminosis D) and high calcium levels (hypercalcemia) include nausea, vomiting, loss of appetite, constipation, increased thirst and urination, and muscle weakness.

Increased amounts of vitamin D during pregnancy can potentially harm an unborn baby. Drisdol should only be used during pregnancy if the potential benefits outweigh the risks and only under a doctor’s supervision.

As a fat-soluble vitamin, Drisdol is best absorbed when taken with a meal that contains some fat. Taking it consistently with food can improve its effectiveness.

Due to potential risks, a doctor will order frequent blood tests to check your calcium and phosphorus levels. X-rays of bones may also be conducted periodically.

Yes, Drisdol can be prescribed for children with refractory rickets that does not respond to standard treatment. The amount is individualized based on age, weight, and the severity of the condition, and must be closely supervised by a doctor.