The precise mechanism of calcipotriol in remitting psoriasis is not well-understood. However, it has been shown to have comparable affinity with calcitriol for the Vitamin D receptor, while being less than 1% as active as the calcitriol in regulating calcium metabolism. The Vitamin D receptor (VDR) belongs to the steroid/thyroid receptor superfamily, and is found on the cells of many different tissues including the thyroid, bone, kindney, and T cells of the immune system. T cells are known to play a role in psoriasis, and it is thought that the binding of calcipotriol to the VDR modulates the T cells gene transcription of cell differentiation and proliferation related genes.
Calcipotriene is a synthetic analog of vitamin D. In humans, the natural supply of vitamin D depends mainly on exposure to the ultraviolet rays of the sun for conversion of 7-dehydrocholesterol to vitamin D3 (cholecalciferol) in the skin.
Hepatic. Calcipotriene metabolism following systemic uptake is rapid, and occurs via a similar pathway to the natural hormone. The primary metabolites are much less potent than the parent compound.
Topically applied calcipotriene can be absorbed in sufficient amounts to produce systemic effects. Elevated serum calcium has been observed with excessive use of calcipotriene.