Такролимус

Tacrolimus, isolated from the microorganism Streptomyces tsukubaensis, is a macrolide immunosuppressant developed by Fujisawa for organ transplantation. It displays similar but more potent immunosuppressive activity than cyclosporin. It inhibits both cell mediated and humoral immune responses. In animal models of organ transplantation, tacrolimus has been shown to prolong survival of hepatic, renal, cardiac, small intestine, pancreatic and skin allografts and to reverse cardiac and renal allograft rejection. It has been used effectively in humans as rescue or primary immunosuppressant therapy in liver or kidney transplantation. Compared to cyclosporin, tacrolimus causes reduced incidence of infectious complications and of hypertension and hypercholesterolemia for the allograft recipients. In common with cyclosporin, tacrolimus binds with high affinity to a family of cytoplasmic immunosuppressant binding proteins, the immunophilins. This tight complex is proposed as the biologically active moiety that interacts with intracellular molecules involved in signal transduction.It inhibits phosphatase activity of calcineurin, an action that may impair the generation and/or activation of nuclear transcription factors required for lymphokine (particularly interleukin-2) gene expression. Tacrolimus has also been reported to have potential in multiple sclerosis, psoriasis, rheumatoid arthritis and uveitis associated with Behcet‘s disease.

White Crystalline Solid

FK-506 (Tacrolimus) is a macrolide immunosuppressive drug that is mainly used after allogeneic organ transplant to reduce the activity of the patient's immune system

ChEBI: Tacrolimus is a macrolide containing a 23-membered lactone ring, originally isolated from the fermentation broth of a Japanese soil sample that contained the bacteria Streptomyces tsukubaensis.

Tacrolimus is a macrolide lactone originally derived from Streptomyces tsukubaensis. Although structurally unrelated to cyclosporine, tacrolimus has a very similar mechanism of action; that is, it blocks the production of proinflammatory cytokines by T lymphocytes by inhibiting calcineurin.Tacrolimus, however, appears to be 10 to 100 times as potent as an immunosuppressive. Oral tacrolimus (FK506) is used for prevention of organ rejection in recipients of renal and hepatic transplants.

Immunosuppressant that blocks T-cell proliferation in vitro by inhibiting the generation of several lymphokines, especially IL-2. Shown to inhibit the activity of FK-506 Binding Protein, thereby reversing its effects on sarcoplamic reticulum Ca²⁺ release. Shown to inhibit the Ca²⁺-dependent phosphatase, Calcineurin (Cat. No. 539565), as well as Na⁺-K⁺-ATPase in nephron segments. Also shown to inhibit aldosterone-induced synthesis of Giα-3 protein.

A topical formulation (Protopic) has recently been approved for treatment of moderate to severe atopic dermatitis in children and adults who have not responded to other therapies. Levels of systemic absorption are low even when applied to a relatively large body surface area.

Local irritant reactions (burning, stinging, erythema) are a common side effect, but these usually resolve within the first few days of treatment. The major benefit of topical tacrolimus over topical corticosteroids is that tacrolimus does not cause atrophy, striae, or telangiectasia, even with chronic use.