tacrolimus tacrolimus tacrolimus, sold under the brand name prograf among others, is an immunosuppressive drug. after allogenic organ transplant, the risk of organ rejection is moderate. to lower the risk of organ rejection, tacrolimus is given. the drug can also be sold as a topical medication in the treatment of t-cell-mediated diseases such as eczema and psoriasis. for example, it is prescribed for severe refractory uveitis after a bone marrow transplant, exacerbations of minimal change disease, kimura's disease, and vitiligo. it can be used to treat dry eye syndrome in cats and dogs. tacrolimusclinical datatrade namesprograf, advagraf, protopic, othersother namesfk-506, fujimycinahfs/drugs.commonographmedlineplusa601117license data eu ema: by inn us dailymed: tacrolimus pregnancycategory au: c routes ofadministrationtopical, by mouth, intravenousatc coded11ah01 (who) l04ad02 (who)legal statuslegal status us: ℞-only eu: rx-only in general: ℞ (prescription only) pharmacokinetic databioavailability24% (5–67%), less after eating food rich in fatprotein binding≥98.8%metabolismliver cyp3a4, cyp3a5elimination half-life11.3 h for transplant patients (range 3.5–40.6 h)excretionmostly fecalidentifiers iupac name (−)-(3s,4r,5s,8r,9e,12s,14s,15r,16s,18r,26as)-8-allyl-5,6,8,11,12,13,14,15,16,17,18,19,24,25,26,26a-hexadecahydro-5,19-dihydroxy-3--14,16-dimethoxy-4,10,12,18-tetramethyl-15,19-epoxy-3h-pyridooxaazacyclotricosane-1,7,20,21(4h,23h)-tetrone cas number104987-11-3 ypubchem cid445643drugbankdb00864 ychemspider393220 yuniiy5l2157c4jkeggd08556 yd00107 ychebichebi:61049chemblchembl269732 ypdb ligandfk5 (pdbe, rcsb pdb)comptox dashboard (epa)dtxsid5046354 echa infocard100.155.367 chemical and physical dataformulac44h69no12molar mass804.031 g·mol−13d model (jsmol)interactive image smiles o=c3c(=o)n1cccc1c(=o)o(c(=c/2cc(o)(oc)c2)/c)(c)(o)cc(=o)(/c=c(/c(c(oc)4o3(o)(c)c4oc)c)c)c\c=c inchi inchi=1s/c44h69no12/c1-10-13-31-19-25(2)18-26(3)20-37(54-8)40-38(55-9)22-28(5)44(52,57-40)41(49)42(50)45-17-12-11-14-32(45)43(51)56-39(29(6)34(47)24-35(31)48)27(4)21-30-15-16-33(46)36(23-30)53-7/h10,19,21,26,28-34,36-40,46-47,52h,1,11-18,20,22-24h2,2-9h3/b25-19+,27-21+/t26-,28+,29+,30-,31+,32-,33+,34-,36+,37-,38-,39+,40+,44+/m0/s1 ykey:qjjxyppxxyfbgm-lfznuxcksa-n y ny (what is this?) (verify) tacrolimus inhibits calcineurin, which is involved in the production of interleukin-2, a molecule that promotes the development and proliferation of t cells, as part of the body's learned (or adaptive) immune response. chemically, it is a macrolide lactone that was first discovered in 1987, from the fermentation broth of a japanese soil sample that contained the bacterium streptomyces tsukubensis. it is on the world health organization's list of essential medicines. medical uses organ transplantation 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 at specific times after medication administration. skin