Alfacalcidol (or 1-hydroxycholecalciferol) is an analogue of vitamin D used for supplementation in humans and as a poultry feed additive. Alfacalcidol has a weaker impact on calcium metabolism and parathyroid hormone levels than calcitriol, however alfacalcidol has significant effects on the immune system, including regulatory T cells. It is considered to be a more useful form of vitamin D supplementation, mostly due to much longer half-life and lower kidney load. It is the most commonly prescribed vitamin D metabolite for patients with

end stage renal disease Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

, given that impaired renal function alters the ability to carry out the second

hydroxylation In chemistry, hydroxylation can refer to: *(i) most commonly, hydroxylation describes a chemical process that introduces a hydroxyl group () into an organic compound. *(ii) the ''degree of hydroxylation'' refers to the number of OH groups in a ...

step required for the formation of the physiologically active form of vitamin D, 1,25-dihydroxyvitamin D3. Alfacalcidol is an active vitamin D3 metabolite, and therefore does not require the second

step in the kidney. It was patented in 1971 and approved for medical use in 1978.

Trade names

Pharmaceutical trade names include AlphaD and One-Alpha.

Other animals

Used as a poultry feed additive, it prevents

tibial dyschondroplasia Tibial dyschondroplasia (TD) is a metabolic disease of young poultry that affects the growth of bone and cartilage. Often occurs in broilers (chickens raised for meat) and other poultry which have been bred for fast growth rates. The tibial cart ...

and increases phytate bioavailability.VDI Product Data
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References

{{Vitamin D receptor modulators Secosteroids Vitamin D Vinylidene compounds