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[3] and
parathyroid hormone levels[4] than
calcitriol; but significant effects on the
immune system, including
regulatory T cells.[5] It is considered to be a more useful form of
vitamin D supplementation, mostly due to much longer half-life and lower kidney load.[6] It is the most commonly prescribed vitamin D metabolite for patients with
end stage renal disease, given that impaired renal function alters the ability to carry out the second
hydroxylation 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
hydroxylation step in the
kidney.[7]
It was patented in 1971 and approved for medical use in 1978.[8]
Trade names
Pharmaceutical trade names include AlphaD and One-Alpha.
^Zold E, Szodoray P, Nakken B, Barath S, Kappelmayer J, Csathy L, et al. (January 2011). "Alfacalcidol treatment restores derailed immune-regulation in patients with undifferentiated connective tissue disease". Autoimmunity Reviews. 10 (3): 155–62.
doi:
10.1016/j.autrev.2010.09.018.
hdl:2437/180066.
PMID20868777.
^Nuti R, Bianchi G, Brandi ML, Caudarella R, D'Erasmo E, Fiore C, et al. (March 2006). "Superiority of alfacalcidol compared to vitamin D plus calcium in lumbar bone mineral density in postmenopausal osteoporosis". Rheumatology International. 26 (5): 445–53.
doi:
10.1007/s00296-005-0073-4.
PMID16283320.
S2CID9931256.
^Ritzerfeld M, Klasser M, Mann H (December 2001). "Alfacalcidol in the therapy of renal bone disease". International Journal of Clinical Pharmacology and Therapeutics. 39 (12): 546–50.
doi:
10.5414/cpp39546.
PMID11770836.