Products
Ergocalciferol (vitamin D2, calciferol) is commercially available in many countries, including as a dietary supplement in the form of capsules. Vitamin D2 is much less commonly used than cholecalciferol (vitamin D3) in many countries. In the United States, on the other hand, ergocalciferol is more traditionally used.
Structure and properties
Ergocalciferol (C28H44O, Mr = 396.6 g/mol) exists as a white to pale yellow powder or as white crystals and is practically insoluble in water. It dissolves in ethanol or fatty oils. The substance is sensitive to air, heat and light. Ergocalciferol is derived from ergosterol, a component of fungal cell membrane and can be extracted from it by UV radiation. This occurs naturally and can be further enhanced by artificial UV radiation. Vitamin D2 is mainly found in fungi and some plants and is therefore suitable for vegans. Cholecalciferol, on the other hand, is usually derived from lanolin and has an animal origin. Vitamin D3 is bioidentical because it is also produced in the human skin. It should be noted that vitamin D3 can also be produced from plant sources (lichens).
Effects
Ergocalciferol (ATC A11CC01), like cholecalciferol, is a prohormone (a precursor) and must be metabolically activated in the body. It is first hydroxylated in the liver and then in the kidney. Due to these conversion steps, the effect occurs with a time delay. Vitamin D plays a central role in the regulation of calcium and phosphate balance. Vitamin D deficiency leads to rickets and bone decalcification. Vitamin D2 is less potent than vitamin D3 (cholecalciferol) and therefore must be dosed higher. In the literature, cholecalciferol is usually recommended because it appears to be more effective (e.g., Tripkovic et al., 2012; Houghton, Vieth, 2006). However, vitamin D2 may be an alternative for individuals who wish to avoid products of animal origin.
Indications
For the prevention and treatment of vitamin D deficiency.
Dosage
According to the SmPC. Ergocalciferol is administered in the form of suitable preparations perorally and, less frequently, intramuscularly.
Contraindications
Contraindications include:
- Hypersensitivity
- Hypercalcemia
- Hypervitaminosis D
Full precautions can be found in the drug label.
Adverse effects
As a dietary supplement, vitamin D2 is usually well tolerated. Hypercalcemia may develop at high doses.
