Calcipotriol

Calcipotriol (INN) or calcipotriene (USAN) is a synthetic derivative of calcitriol or Vitamin D. It is used in the treatment of psoriasis, marketed under the trade name Dovonex®.

Mechanism
The efficacy of calcipotriol in the treatment of psoriasis was first noticed by the observation of patients receiving various forms of Vitamin D in an osteoporosis study. Unexpectedly, a patient's psoriasis lesions dramatically disappeared.

The precise mechanism of calcipotriol in remitting psoriasis is not well-understood. However, it has been shown to have comparable affinity with calcitriol (Vit D) 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.

Usage and Efficacy
Available as a cream, ointment or scalp solution (50mcg/mL), Calcipotriol is applied twice daily to plaque psoriasis on the body or scalp, but not the face. Improvement is usually detectable within 2 weeks. Most patients show some improvement, slightly more so than is seen with the use of corticosteroids alone. Tachyphylaxis does not occur, an improvement over glucocorticoid therapy.

Side effects
Calcipotriol has been shown in clinical trials to have an excellent safety profile. Reports of hypercalcemia are rare.

It is also available in combination with the synthetic glucocorticoid betamethasone under the trade name Dovobet®.