Vitamin D2 Uses

Vitamin D2 is used to treat vitamin D deficiency and medical conditions such as hypoparathyroidism (low levels of parathyroid hormone), familial hypophosphatemia (a genetic condition in which there is an inability to breakdown vitamin D in the body, resulting in low phosphate levels, rickets and osteomalacia, i.e., soft bones in children and adults, respectively), and refractory rickets (soft and weak bones in children due to prolonged and severe vitamin D deficiency that does not respond to other treatments). 

There may be other uses of vitamin D2—your pharmacist or doctor can give you further drug information.

Vitamin D2 Mechanism of Action

Ergocalciferol (vitamin D2) is a dietary supplement. It is absorbed by the intestines and converted into 1,25-dihydroxyvitamin D or calcitriol in the body. Vitamin D helps the body absorb calcium. Calcium and vitamin supplements may be necessary to maintain bone health if dietary intake is inadequate.

Vitamin D2 Doses

There is only a small difference between the therapeutic and toxic doses of ergocalciferol (vitamin D2). Increased vitamin D levels above the therapeutic range can be harmful. Therefore, the dose of a vitamin D supplement (vitamin D2) is carefully individualized and given under medical supervision. In addition, you need adequate calcium intake along with taking vitamin D. 

Depending on the condition being treated, blood calcium and phosphorus levels are measured at least every 2 weeks and bone x-rays are obtained every month until the condition is stabilized or treated. 

The typical ergocalciferol dose is as follows:

• Hypoparathyroidism: 50,000 to 200,000 USP units daily
• Hypophosphatemia: Individual dose
• Refractory rickets: 12,000 to 500,000 USP units daily

A child’s dose (for example, a child taking ergocalciferol for refractory rickets) needs to be monitored very carefully, as there is only a small difference between a safe and dangerous dose.

Note: Vitamin D is present in many supplements, including multivitamins. Check the labels of all your vitamins and make sure you are not getting vitamin D from multiple sources.