Tacrolimus

Tacrolimus, also known as fujimycin or FK506, is an immunosuppressive drug used mainly after allogeneic organ transplant to lower the risk of organ rejection. It achieves this by inhibiting the production of interleukin-2, a molecule that promotes the development and proliferation of T cells, which are vital to the body's learned (or adaptive) immune response. Tacrolimus is also used in the treatment of other T cell-mediated diseases such as eczema and psoriasis. (for which it is applied to the skin in a medicated ointment), severe refractory uveitis after bone marrow transplants, exacerbations of minimal change disease, Kimura's disease, and the skin condition vitiligo. Tacrolimus, also known as fujimycin or FK506, is an immunosuppressive drug used mainly after allogeneic organ transplant to lower the risk of organ rejection. It achieves this by inhibiting the production of interleukin-2, a molecule that promotes the development and proliferation of T cells, which are vital to the body's learned (or adaptive) immune response. Tacrolimus is also used in the treatment of other T cell-mediated diseases such as eczema and psoriasis. (for which it is applied to the skin in a medicated ointment), severe refractory uveitis after bone marrow transplants, exacerbations of minimal change disease, Kimura's disease, and the skin condition vitiligo. Chemically it is a 23-membered macrolide lactone that was first discovered in 1987 from the fermentation broth of a Japanese soil sample that contained the bacterium Streptomyces tsukubaensis. Tacrolimus is also used to treat dry eye syndrome in cats and dogs. It has similar immunosuppressive properties to ciclosporin, but is much more potent. Immunosuppression with tacrolimus was associated with a significantly lower rate of acute rejection compared with ciclosporin-based immunosuppression (30.7% vs 46.4%) in one study. Clinical outcome is better with tacrolimus than with ciclosporin during the first year of liver transplantation. Long-term outcome has not been improved to the same extent. Tacrolimus is normally prescribed as part of a post-transplant cocktail including steroids, mycophenolate, and IL-2 receptor inhibitors such as basiliximab. Dosages are titrated to target blood levels. In recent years, tacrolimus has been used to suppress the inflammation associated with ulcerative colitis (UC), a form of inflammatory bowel disease. Although almost exclusively used in trial cases only, tacrolimus has shown to be significantly effective in the suppression of flares of UC. As an ointment, tacrolimus is used in the treatment of eczema, in particular atopic dermatitis. It suppresses inflammation in a similar way to steroids, and is equally as effective as a mid-potency steroid. An important advantage of tacrolimus is that, unlike steroids, it does not cause skin thinning (atrophy), or other steroid related side effects. It is applied on the active lesions until they heal off, but may also be used continuously in low doses (twice a week), and applied to the thinner skin over the face and eyelids. Clinical trials of up to one year have been conducted. Recently it has also been used to treat segmental vitiligo in children, especially in areas on the face. Tacrolimus has been shown to reduce the risk of serious infection in lupus nephritis, when compared to other agents.