Vitamin D2

Ergocalciferol

Clinical data
Trade names	Drisdol, Calcidol, others
Synonyms	viosterol
AHFS/Drugs.com	Monograph
Pregnancy category	US: A (No risk in human studies) and C
ATC code	A11CC01 (WHO)
Legal status
Legal status	US: OTC
Identifiers
IUPAC name (3β,5Z,7E,22E)-9,10-secoergosta-5,7,10(19),22-tetraen-3-ol
CAS Number	50-14-6  Y
PubChem CID	5280793
DrugBank	DB00153
ChemSpider	4444351
UNII	VS041H42XC
KEGG	C05441
ChEBI	CHEBI:28934
ChEMBL	CHEMBL1536
ECHA InfoCard	100.000.014
Chemical and physical data
Formula	C28H44O
Molar mass	396.65 g/mol
3D model (JSmol)	Interactive image
Melting point	114 to 118 °C (237 to 244 °F)
SMILES O[C@@H]1CC(\C(=C)CC1)=C\C=C2/CCC[C@]3([C@H]2CC[C@@H]3[C@@H](/C=C/[C@H](C)C(C)C)C)C
InChI InChI=1S/C28H44O/c1-19(2)20(3)9-10-22(5)26-15-16-27-23(8-7-17-28(26,27)6)12-13-24-18-25(29)14-11-21(24)4/h9-10,12-13,19-20,22,25-27,29H,4,7-8,11,14-18H2,1-3,5-6H3/b10-9+,23-12+,24-13-/t20-,22+,25-,26+,27-,28+/m0/s1  Y Key:MECHNRXZTMCUDQ-RKHKHRCZSA-N

Ergocalciferol, also known as vitamin D₂ and calciferol, is a type of vitamin D found in food and used as a dietary supplement. As a supplement it is used to prevent and treat vitamin D deficiency. This includes vitamin D deficiency due to poor absorption by the intestines or liver disease. It may also be used for low blood calcium due to hypoparathyroidism. It is used by mouth or injection into a muscle.

Excessive doses can result in increased urine production, high blood pressure, kidney stones, kidney failure, weakness, and constipation. If high doses are taken for a long period of time, tissue calcification may occur. It is recommended that people on high doses have their blood calcium levels regularly checked. Normal doses are safe in pregnancy. It works by increasing the amount of calcium absorbed by the intestines and kidneys. Food in which it is found include some mushrooms.

Ergocalciferol was first described in 1936. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Ergocalciferol is available as a generic medication and over the counter. In the United Kingdom a typical dose costs the NHS less than 10 pounds a month. Certain foods such as breakfast cereal and margarine have ergocalciferol added to them in some countries.