Tacalcitol (TC)

Tacalcitol (1,24-dihydroxyvitamin D3) is a synthetic vitamin D3 analog. Tacalcitol reduces excessive cell turnover in the epidermis by interacting with vitamin D receptors on keratinocytes. It is usually prescribed by a general practitioner or dermatologist for the treatment of psoriasis, chronic chapped lips and other severe dry skin conditions because of its ability to reduce excessive skin cell turnover. It is available as an ointment or lotion. It has also been used for vitiligo and Hailey-Hailey disease. Tacalcitol is a vitamin D3 analogue which is available in Japan as a 2 micrograms/g ointment for twice daily application and in Western markets as a 4 micrograms/g ointment for once daily application. Tacalcitol inhibits proliferation, and induces the differentiation, of keratinocytes. In addition, it appears to modulate inflammatory and immunological mediators in the skin which may be involved in the aetiology of psoriasis.