Ergocalciferol

Ergocalciferol
Clinical data
Trade names	Drisdol, Calcidol, others
Other names	vitamin D2
AHFS/Drugs.com	Monograph
MedlinePlus	a616042
License data	US DailyMed: Ergocalciferol;
Routes of; administration	By mouth, intramuscular
ATC code	A11CC01 (WHO) ;
Legal status
Legal status	CA: ℞-only; UK: POM (Prescription only); US: OTC / Rx-only;
Identifiers
	IUPAC name (3S,5Z,7E,22E)-9,10-secoergosta-5,7,10(19),22-tetraen-3-ol;
CAS Number	50-14-6;
PubChem CID	5280793;
DrugBank	DB00153;
ChemSpider	4444351;
UNII	VS041H42XC;
KEGG	C05441;
ChEBI	CHEBI:28934;
ChEMBL	ChEMBL1536;
CompTox Dashboard (EPA)	DTXSID5020233 ;
ECHA InfoCard	100.000.014
Chemical and physical data
Formula	C28H44O
Molar mass	396.659 g·mol−1
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 ; Key:MECHNRXZTMCUDQ-RKHKHRCZSA-N;

Ergocalciferol, also known as vitamin D₂ and nonspecifically calciferol, is a type of vitamin D found in food. It is used as a dietary supplement to prevent and treat 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 taken by mouth or via injection into a muscle.

Excessive doses can result in vitamin D toxicity causing increased urine production, high blood pressure, kidney stones, kidney failure, muscle weakness, and constipation. If high doses are taken for a long period of time, tissue calcification may occur. Normal doses are safe in pregnancy. It works by increasing the amount of calcium absorbed by the intestines and reabsorbed by the kidneys. Food in which it is found include some mushrooms.

Ergocalciferol was first described in 1936. Ergocalciferol is available as a generic medication and over the counter. In 2022, it was the 38th most commonly prescribed medication in the United States, with more than 15 million prescriptions. Certain foods such as breakfast cereal and margarine have ergocalciferol added to them in some countries. It is on the World Health Organization's List of Essential Medicines.