Tacrolimus

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.{{cite web | vauthors = McCauley J |date=19 May 2004 | url = http://www.medscape.com/viewarticle/474429 | title=Long-Term Graft Survival In Kidney Transplant Recipients | work=Slide Set Series on Analyses of Immunosuppressive Therapies | publisher=Medscape | access-date=6 June 2006}} Clinical outcome is better with tacrolimus than with ciclosporin during the first year of liver transplantation.{{cite journal | vauthors = Haddad EM, McAlister VC, Renouf E, Malthaner R, Kjaer MS, Gluud LL | title = Cyclosporin versus tacrolimus for liver transplanted patients | journal = The Cochrane Database of Systematic Reviews | volume = 2006 | issue = 4 | pages = CD005161 | date = October 2006 | pmid = 17054241 | pmc = 8865611 | doi = 10.1002/14651858.CD005161.pub2 | veditors = McAlister V }}{{cite journal | vauthors = O'Grady JG, Burroughs A, Hardy P, Elbourne D, Truesdale A | title = Tacrolimus versus microemulsified ciclosporin in liver transplantation: the TMC randomised controlled trial | journal = Lancet | volume = 360 | issue = 9340 | pages = 1119–1125 | date = October 2002 | pmid = 12387959 | doi = 10.1016/S0140-6736(02)11196-2 | s2cid = 10417106 }} 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.{{cite journal | vauthors = Lee MN, Butani L | title = Improved pharmacokinetic monitoring of tacrolimus exposure after pediatric renal transplantation | journal = Pediatric Transplantation | volume = 11 | issue = 4 | pages = 388–393 | date = June 2007 | pmid = 17493218 | doi = 10.1111/j.1399-3046.2006.00618.x | s2cid = 23530214 | doi-access = free }}

{{See also|Eczema#Medications|l1=Medications used in treatment of eczema}}

File:Protopic.JPG

As an ointment, tacrolimus is used in the treatment of dermatitis (eczema), in particular atopic dermatitis, if topical corticosteroids and moisturisers fail in helping.{{cite journal |vauthors = Cury Martins J, Martins C, Aoki V, Gois AF, Ishii HA, da Silva EM |title = Topical tacrolimus for atopic dermatitis |journal = The Cochrane Database of Systematic Reviews |volume = 2015 |issue = 7 |pages = CD009864 |date = July 2015 |pmid = 26132597 |pmc = 6461158 |doi = 10.1002/14651858.CD009864.pub2 }}{{cite journal |vauthors = Devasenapathy N, Chu A, Wong M, Srivastava A, Ceccacci R, Lin C, MacDonald M, Wen A, Steen J, Levine M, Pyne L, Schneider L, Chu DK |title = Cancer risk with topical calcineurin inhibitors, pimecrolimus and tacrolimus, for atopic dermatitis: a systematic review and meta-analysis |journal = The Lancet. Child & Adolescent Health |volume = 7 |issue = 1 |pages = 13–25 |date = January 2023 |pmid = 36370744 |doi = 10.1016/S2352-4642(22)00283-8 |s2cid = 253470127 }} 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.{{Citation needed|date=December 2008}} 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.{{cite journal |vauthors = Silverberg NB, Lin P, Travis L, Farley-Li J, Mancini AJ, Wagner AM, Chamlin SL, Paller AS |title = Tacrolimus ointment promotes repigmentation of vitiligo in children: a review of 57 cases |journal = Journal of the American Academy of Dermatology |volume = 51 |issue = 5 |pages = 760–766 |date = November 2004 |pmid = 15523355 |doi = 10.1016/j.jaad.2004.05.036 }}

Tacrolimus solution, as drops, is sometimes prescribed by veterinarians for keratoconjunctivitis, and other dry eye maladies, in the eyes of domestic cats, dogs, and horses.{{cite web| publisher=Plumbs Veterinary Medication Guides| title=Tacrolimus, Ophthalmic| date=2017| url=https://www.mspca.org/wp-content/uploads/2017/04/Plumbs-Tacrolimus-Ophthalmic.pdf| access-date=5 August 2022| archive-date=18 December 2022| archive-url=https://web.archive.org/web/20221218152242/https://www.mspca.org/wp-content/uploads/2017/04/Plumbs-Tacrolimus-Ophthalmic.pdf| url-status=dead}} It has been studied for use in human eyes.{{cite web| publisher=U.S. National Library of Medicine| title=Treatment of Dry Eye Using 0.03% Tacrolimus Eye Drops| date=10 May 2013| url=https://clinicaltrials.gov/ct2/show/NCT01850979| access-date=5 August 2022| vauthors = Naves FE, Sakassegawa E }}{{cite journal | vauthors = Yazu H, Fukagawa K, Shimizu E, Sato Y, Fujishima H | title = Long-term outcomes of 0.1% tacrolimus eye drops in eyes with severe allergic conjunctival diseases | journal = Allergy, Asthma, and Clinical Immunology | volume = 17 | issue = 1 | pages = 11 | date = February 2021 | pmid = 33522964 | pmc = 7852099 | doi = 10.1186/s13223-021-00513-w | doi-access = free }}

Contraindications and precautions include:

• Hepatic disease
• Immunosuppression
• Infants
• Infection
• Neoplastic disease, such as:
• Skin cancer
• Lung cancer
• Oliguria
• Pregnancy
• QT interval prolongation
• Sunlight (UV) exposure
• Grapefruit juice{{cite journal | vauthors = Fukatsu S, Fukudo M, Masuda S, Yano I, Katsura T, Ogura Y, Oike F, Takada Y, Inui K | title = Delayed effect of grapefruit juice on pharmacokinetics and pharmacodynamics of tacrolimus in a living-donor liver transplant recipient | journal = Drug Metabolism and Pharmacokinetics | volume = 21 | issue = 2 | pages = 122–125 | date = April 2006 | pmid = 16702731 | doi = 10.2133/dmpk.21.122 }}

• Occlusive dressing
• Known or suspected malignant lesions
• Netherton's syndrome or similar skin diseases
• Certain skin infections{{cite book|title=Austria-Codex|editor=Haberfeld, H|at=Protopic|publisher=Österreichischer Apothekerverlag|location=Vienna|year=2015|language=de}}

Side effects can be severe and include infection, cardiac damage, hypertension, blurred vision, liver and kidney problems (tacrolimus nephrotoxicity),{{cite journal | vauthors = Naesens M, Kuypers DR, Sarwal M | title = Calcineurin inhibitor nephrotoxicity | journal = Clinical Journal of the American Society of Nephrology | volume = 4 | issue = 2 | pages = 481–508 | date = February 2009 | pmid = 19218475 | doi = 10.2215/CJN.04800908 | doi-access = free }} hyperkalemia, hypomagnesemia, hyperglycemia, diabetes mellitus, itching, lung damage (sirolimus also causes lung damage),{{cite journal | vauthors = Miwa Y, Isozaki T, Wakabayashi K, Odai T, Matsunawa M, Yajima N, Negishi M, Ide H, Kasama T, Adachi M, Hisayuki T, Takemura T | title = Tacrolimus-induced lung injury in a rheumatoid arthritis patient with interstitial pneumonitis | journal = Modern Rheumatology | volume = 18 | issue = 2 | pages = 208–211 | year = 2008 | pmid = 18306979 | doi = 10.1007/s10165-008-0034-3 | s2cid = 39537409 }} and various neuropsychiatric problems such as loss of appetite, insomnia, posterior reversible encephalopathy syndrome, confusion, weakness, depression, vivid nightmares, cramps, neuropathy, seizures, tremors, and catatonia.{{cite journal | vauthors = O'Donnell MM, Williams JP, Weinrieb R, Denysenko L | title = Catatonic mutism after liver transplant rapidly reversed with lorazepam | journal = General Hospital Psychiatry | volume = 29 | issue = 3 | pages = 280–281 | year = 2007 | pmid = 17484951 | doi = 10.1016/j.genhosppsych.2007.01.004 }}

In addition, it may potentially increase the severity of existing fungal or infectious conditions such as herpes zoster or polyoma viral infections.

In people receiving immunosuppressants to reduce transplant graft rejection, an increased risk of malignancy (cancer) is a recognised complication. The most common cancers are non-Hodgkin's lymphoma{{Cite web|url=https://www.cancer.org/cancer/non-hodgkin-lymphoma/about/key-statistics.html|title=Key Statistics for Non-Hodgkin Lymphoma|website=www.cancer.org|access-date=19 February 2020}} and skin cancers. The risk appears to be related to the intensity and duration of treatment.

The most common adverse events associated with the use of topical tacrolimus ointments, especially if used over a wide area, include a burning or itching sensation on the initial applications, with increased sensitivity to sunlight and heat on the affected areas.{{Citation needed|date=January 2022}} Less common are flu-like symptoms, headache, cough, and burning eyes.{{cite journal | vauthors = Hanifin JM, Paller AS, Eichenfield L, Clark RA, Korman N, Weinstein G, Caro I, Jaracz E, Rico MJ | title = Efficacy and safety of tacrolimus ointment treatment for up to 4 years in patients with atopic dermatitis | journal = Journal of the American Academy of Dermatology | volume = 53 | issue = 2 Suppl 2 | pages = S186–S194 | date = August 2005 | pmid = 16021174 | doi = 10.1016/j.jaad.2005.04.062 }}

{{Further|Eczema#Medications}}

Tacrolimus and a related drug for eczema (pimecrolimus) were suspected of carrying a cancer risk, though the matter is still a subject of controversy. The FDA issued a health warning in March 2005 for the drug, based on animal models and a small number of patients. Until further human studies yield more conclusive results, the FDA recommends that users be advised of the potential risks. However, current practice by UK dermatologists is not to consider this a significant real concern and they are increasingly recommending the use of these new drugs.{{cite web | vauthors = Cox NH, Smith CH |date=December 2002 |url=http://www.bad.org.uk/Portals/_Bad/Guidelines/Position%20Statements%20&%20Other%20Documents/Advice%20re%20topical%20tacrolimus.pdf |title=Advice to dermatologists re topical tacrolimus |work=Therapy Guidelines Committee |publisher=British Association of Dermatologists |url-status=dead |archive-url=https://web.archive.org/web/20131213072822/http://www.bad.org.uk/Portals/_Bad/Guidelines/Position%20Statements%20%26%20Other%20Documents/Advice%20re%20topical%20tacrolimus.pdf |archive-date=13 December 2013 }} A 2023 systematic review and meta-analysis published in The Lancet Child & Adolescent Health concluded with moderate-certainty evidence that the two drugs were not associated with any increased risk of cancer.{{cite journal | vauthors = Devasenapathy N, Chu A, Wong M, Srivastava A, Ceccacci R, Lin C, MacDonald M, Wen A, Steen J, Levine M, Pyne L, Schneider L, Chu DK | title = Cancer risk with topical calcineurin inhibitors, pimecrolimus and tacrolimus, for atopic dermatitis: a systematic review and meta-analysis | language = English | journal = The Lancet. Child & Adolescent Health | volume = 7 | issue = 1 | pages = 13–25 | date = January 2023 | pmid = 36370744 | doi = 10.1016/S2352-4642(22)00283-8 | s2cid = 253470127 }}

In November 2024, International Agency for Research on Cancer (IARC) classified hydrochlorothiazide, voriconazole and tacrolimus as group 1 carcinogens.{{cite journal |url=https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(24)00685-5/fulltext |title=Carcinogenicity of hydrochlorothiazide, voriconazole, and tacrolimus |journal=The Lancet Oncology|date=2024-11-29 |volume=26 |issue=1 |pages=15–16 |doi=10.1016/S1470-2045(24)00685-5 |author=Cogliano VJ, Corsini E, Fournier A, Nelson HH, Sergi CM, Antunes AMM|display-authors=etal}}{{cite web |url=https://monographs.iarc.who.int/list-of-classifications |title=List of Classifications|work=IARC|access-date=2025-04-12}}

Also like cyclosporin, it has a wide range of interactions. Tacrolimus is primarily metabolised by the cytochrome P450 system of liver enzymes, and there are many substances that interact with this system and induce or inhibit the system's metabolic activity.{{cite book|title=Austria-Codex|editor=Haberfeld, H|at=Prograf|publisher=Österreichischer Apothekerverlag|location=Vienna|year=2015|language=de}}

Interactions include that with grapefruit which increases tacrolimus plasma concentrations. As infections are a major cause of morbidity and mortality in the post-transplant patient, the most commonly{{citation needed|date=October 2016}} reported interactions include interactions with anti-microbial drugs. Macrolide antibiotics including erythromycin and clarithromycin, as well as several of the newer classes of antifungals, especially of the azole class (fluconazole, voriconazole), increase tacrolimus levels by competing for cytochrome enzymes.

File:PDB 1fkk EBI.jpg, the target protein of tacrolimus]]

Tacrolimus is a macrolide calcineurin inhibitor. In T cells, activation of the T cell receptor normally increases intracellular calcium, which acts via calmodulin to activate calcineurin. Calcineurin then dephosphorylates the transcription factor nuclear factor of activated T cells (NF-AT), which moves to the nucleus of the T cell and increases the activity of genes coding for IL-2 and related cytokines. Tacrolimus prevents the dephosphorylation of NF-AT.{{cite book| vauthors = Ganong WF |title= Review of medical physiology|edition=22nd |publisher=Lange medical books|page=530|isbn=978-0-07-144040-0|date= 8 March 2005}}

In detail, tacrolimus reduces peptidylprolyl isomerase activity by binding to the immunophilin FKBP12 (FK506 binding protein), creating a new complex. This FKBP12–FK506 complex interacts with and inhibits calcineurin, thus inhibiting both T lymphocyte signal transduction and IL-2 transcription.{{cite journal | vauthors = Liu J, Farmer JD, Lane WS, Friedman J, Weissman I, Schreiber SL | title = Calcineurin is a common target of cyclophilin-cyclosporin A and FKBP-FK506 complexes | journal = Cell | volume = 66 | issue = 4 | pages = 807–815 | date = August 1991 | pmid = 1715244 | doi = 10.1016/0092-8674(91)90124-H | s2cid = 22094672 }} Although this activity is similar to that of cyclosporin, the incidence of acute rejection is reduced by tacrolimus use over cyclosporin use. Although short-term immunosuppression concerning patient and graft survival is found to be similar between the two drugs, tacrolimus results in a more favorable lipid profile, and this may have important long-term implications given the prognostic influence of rejection on graft survival.{{cite journal | vauthors = Abou-Jaoude MM, Najm R, Shaheen J, Nawfal N, Abboud S, Alhabash M, Darwish M, Mulhem A, Ojjeh A, Almawi WY | title = Tacrolimus (FK506) versus cyclosporine microemulsion (neoral) as maintenance immunosuppression therapy in kidney transplant recipients | journal = Transplantation Proceedings | volume = 37 | issue = 7 | pages = 3025–3028 | date = September 2005 | pmid = 16213293 | doi = 10.1016/j.transproceed.2005.08.040 }}

Oral tacrolimus is slowly absorbed in the gastrointestinal tract, with a total bioavailability of 20 to 25% (but with variations from 5 to 67%) and highest blood plasma concentrations (C_max) reached after one to three hours. Taking the drug together with a meal, especially one rich in fat, slows down resorption and reduces bioavailability. In the blood, tacrolimus is mainly bound to erythrocytes; only 5% are found in the plasma, of which more than 98.8% are bound to plasma proteins.{{cite book|title=Arzneistoff-Profile|editor1=Dinnendahl, V |editor2=Fricke, U |publisher=Govi Pharmazeutischer Verlag|location=Eschborn, Germany|date=2003|edition=18|volume=9|isbn=978-3-7741-9846-3|language=de}}

The substance is metabolized in the liver, mainly via CYP3A, and in the intestinal wall. All metabolites found in the circulation are inactive. Biological half-life varies widely and seems to be higher for healthy persons (43 hours on average) than for patients with liver transplants (12 hours) or kidney transplants (16 hours), due to differences in clearance. Tacrolimus is predominantly eliminated via the faeces in form of its metabolites.

When applied locally on eczema, tacrolimus has little to no bioavailability.

The predominant enzyme responsible for metabolism of tacrolimus is CYP3A5. Genetic variations within CYP3A5 that result in changes to the activity of the CYP3A5 protein can affect concentrations of tacrolimus within the body. In particular, individuals who are homozygous for the G allele at the single nucleotide polymorphism (SNP) rs776746 (also known as CYP3A5 *3/*3) have a non-functional CYP3A5 protein. The frequency of the G allele varies worldwide, from 4% in some African populations to 80–90% in Caucasian populations.{{cite web| vauthors = Bains RK |title=Molecular diversity and population structure at the CYP3A5 gene in Africa|url=http://discovery.ucl.ac.uk/1356293/7/1356293_R%20Bains%20ELECTRONIC%20VERSION%20thesis%20-%20post%20viva.pdf|publisher=University College London|access-date=13 June 2016}} Across a large number of studies, individuals homozygous for the G allele have been shown to have higher concentrations of tacrolimus and require lower doses of the drug, as compared to individuals who are not homozygous for the G allele. Achieving target concentrations of tacrolimus is important – if levels are too low, then there is a risk of transplant rejection, if levels are too high, there is a risk of drug toxicities. There is evidence to suggest that dosing patients based on rs776746 genotype can result in faster and more frequent achievement of target tacrolimus levels. However, there is a lack of consistent evidence as to whether dosing based on rs776746 genotype results in improved clinical outcomes (such as a decreased risk for transplant rejection or drug toxicities), likely because patients taking tacrolimus are subject to therapeutic drug monitoring.{{cite journal | vauthors = Staatz CE, Tett SE | title = Clinical pharmacokinetics and pharmacodynamics of tacrolimus in solid organ transplantation | journal = Clinical Pharmacokinetics | volume = 43 | issue = 10 | pages = 623–653 | date = 2004 | pmid = 15244495 | doi = 10.2165/00003088-200443100-00001 | s2cid = 33877550 }}{{cite journal | vauthors = Staatz CE, Goodman LK, Tett SE | title = Effect of CYP3A and ABCB1 single nucleotide polymorphisms on the pharmacokinetics and pharmacodynamics of calcineurin inhibitors: Part I | journal = Clinical Pharmacokinetics | volume = 49 | issue = 3 | pages = 141–175 | date = March 2010 | pmid = 20170205 | doi = 10.2165/11317350-000000000-00000 | s2cid = 28346861 }}{{cite journal | vauthors = Staatz CE, Goodman LK, Tett SE | title = Effect of CYP3A and ABCB1 single nucleotide polymorphisms on the pharmacokinetics and pharmacodynamics of calcineurin inhibitors: Part II | journal = Clinical Pharmacokinetics | volume = 49 | issue = 4 | pages = 207–221 | date = April 2010 | pmid = 20214406 | doi = 10.2165/11317550-000000000-00000 | s2cid = 27047235 }}{{cite journal | vauthors = Barbarino JM, Staatz CE, Venkataramanan R, Klein TE, Altman RB | title = PharmGKB summary: cyclosporine and tacrolimus pathways | journal = Pharmacogenetics and Genomics | volume = 23 | issue = 10 | pages = 563–585 | date = October 2013 | pmid = 23922006 | pmc = 4119065 | doi = 10.1097/fpc.0b013e328364db84 }}

Studies have shown that genetic polymorphisms of genes other than CYP3A5, such as NR1I2{{cite journal | vauthors = Benkali K, Prémaud A, Picard N, Rérolle JP, Toupance O, Hoizey G, Turcant A, Villemain F, Le Meur Y, Marquet P, Rousseau A | title = Tacrolimus population pharmacokinetic-pharmacogenetic analysis and Bayesian estimation in renal transplant recipients | journal = Clinical Pharmacokinetics | volume = 48 | issue = 12 | pages = 805–816 | date = 1 January 2009 | pmid = 19902988 | doi = 10.2165/11318080-000000000-00000 | s2cid = 19900291 }}{{cite journal | vauthors = Choi Y, Jiang F, An H, Park HJ, Choi JH, Lee H | title = A pharmacogenomic study on the pharmacokinetics of tacrolimus in healthy subjects using the DMETTM Plus platform | journal = The Pharmacogenomics Journal | volume = 17 | issue = 1 | pages = 105–106 | date = January 2017 | pmid = 27958377 | doi = 10.1038/tpj.2016.85 | doi-access = free }} (encoding PXR), also significantly influence the pharmacokinetics of tacrolimus.

Tacrolimus was discovered in 1987 by a Japanese team led by pharmacologist Tohru Kino; it was among the first macrolide immunosuppressants discovered, preceded by the discovery of rapamycin (sirolimus) on Rapa Nui (Easter Island) in 1975.{{cite journal | vauthors = Kino T, Hatanaka H, Hashimoto M, Nishiyama M, Goto T, Okuhara M, Kohsaka M, Aoki H, Imanaka H | title = FK-506, a novel immunosuppressant isolated from a Streptomyces. I. Fermentation, isolation, and physico-chemical and biological characteristics | journal = The Journal of Antibiotics | volume = 40 | issue = 9 | pages = 1249–1255 | date = September 1987 | pmid = 2445721 | doi = 10.7164/antibiotics.40.1249 | doi-access = free }} It is produced by a soil bacterium, Streptomyces tsukubensis.{{cite journal | vauthors = Pritchard DI | title = Sourcing a chemical succession for cyclosporin from parasites and human pathogens | journal = Drug Discovery Today | volume = 10 | issue = 10 | pages = 688–691 | date = May 2005 | pmid = 15896681 | doi = 10.1016/S1359-6446(05)03395-7 }} Supports source organism, but not team information The name tacrolimus is derived from "Tsukuba macrolide immunosuppressant".Ponner, B, Cvach, B (Fujisawa Pharmaceutical Co.): Protopic Update 2005

The early development (investigational new drug phase) of tacrolimus, called at the time by the development code FK-506, happened in the next several years. A firsthand account of that process is given in Thomas Starzl's 1992 memoir.{{cite book |last=Starzl |first=Thomas E. |date=1992 |chapter=Chapter 25: The drug with no name |pages=288–308 |title=The Puzzle People: Memoirs Of A Transplant Surgeon |publisher=University of Pittsburgh Press |doi=10.2307/j.ctt9qh63b |isbn=978-0-8229-3714-2 |url=https://doi.org/10.2307/j.ctt9qh63b}}

Tacrolimus was first approved by the US Food and Drug Administration (FDA) in 1994,{{cite web | title=Prograf: FDA-Approved Drugs | website=U.S. Food and Drug Administration (FDA) | url=https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=050708 | access-date=29 April 2020}}{{cite web | title=Prograf: FDA-Approved Drugs | website=U.S. Food and Drug Administration (FDA) | url=https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=050709 | access-date=29 April 2020}} for use in liver transplantation; the indications were extended to include kidney transplants.Tacrolimus (Systemic) {{drugs.com|monograph|tacrolimus}}. Accessed 16 December 2021. Generic versions of tacrolimus were approved in the US in 2017.{{cite web | title=Tacrolimus: FDA-Approved Drugs | website=U.S. Food and Drug Administration (FDA) | url=https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=203900 | access-date=29 April 2020}}

Tacrolimus was approved for medical use in the European Union in 2002, for the treatment of moderate to severe atopic dermatitis.{{cite web | title=Protopic EPAR | website=European Medicines Agency (EMA) | date=17 September 2018 | url=https://www.ema.europa.eu/en/medicines/human/EPAR/protopic | access-date=29 April 2020}} {{PD-notice}} In 2007, the indications were expanded to include the prophylaxis of transplant rejection in adult kidney or liver allograft recipients and the treatment of allograft rejection resistant to treatment with other immunosuppressive medicinal products in adults.{{cite web | title=Advagraf EPAR | website=European Medicines Agency (EMA) | date=17 September 2018 | url=https://www.ema.europa.eu/en/medicines/human/EPAR/advagraf | access-date=29 April 2020}} {{PD-notice}} In 2009, the indications were expanded to include the prophylaxis of transplant rejection in adult and paediatric, kidney, liver or heart allograft recipients and the treatment of allograft rejection resistant to treatment with other immunosuppressive medicinal products in adults and children.{{cite web | title=Modigraf EPAR | website=European Medicines Agency (EMA) | date=17 September 2018 | url=https://www.ema.europa.eu/en/medicines/human/EPAR/modigraf | access-date=29 April 2020}}

A branded version of the drug is owned by Astellas Pharma, and is sold under the brand name Prograf, given twice daily. A number of other manufacturers hold marketing authorisation for alternative brands of the twice-daily formulation.{{cite web|last1=Joint Formulary Committee|title=British National Formulary (online)|url=http://www.medicinescomplete.com/|publisher=London: BMJ Group and Pharmaceutical Press|access-date=24 September 2015}}

Once-daily formulations with marketing authorisation include Advagraf (Astellas Pharma) and Envarsus (marketed as Envarsus XR in US by Veloxis Pharmaceuticals and marketed in Europe by Chiesi). These formulations are intended to reduce pharmacokinetic variation in blood levels and facilitate compliance with dosing.{{citation needed|date=April 2020}}

The topical formulation is marketed by LEO Pharma under the name Protopic.

File:Tacrolimus biosynthesis part 1.tif

File:Tacrolimus biosynthesis part 2.tif

File:Tacrolimus biosynthesis part 3..tif

The biosynthesis of tacrolimus is hybrid synthesis of both type 1 polyketide synthases (PKS 1) and nonribosomal peptide syntheses (NRPS). The research shows the hybrid synthesis consists of ten modules of type 1 polyketide synthase and one module of nonribosomal peptide synthase. The synthetic enzymes for tacrolimus are found in 19 gene clusters named fkb. The 19 genes are fkbQ, fkbN, fkbM, fkbD, fkbA, fkbP, fkbO, fkbB, fkbC, fkbL, fkbK, fkbJ, fkbI, fkbH, fkbG, allD, allR, allK and allA.{{cite journal | vauthors = Ordóñez-Robles M, Santos-Beneit F, Martín JF | title = Unraveling Nutritional Regulation of Tacrolimus Biosynthesis in Streptomyces tsukubaensis through omic Approaches | journal = Antibiotics | volume = 7 | issue = 2 | pages = 39 | date = May 2018 | pmid = 29724001 | pmc = 6022917 | doi = 10.3390/antibiotics7020039 | doi-access = free }}

There are several possible ways of biosynthesis of tacrolimus. The fundamental units for biosynthesis are following: one molecule of 4,5-dihydroxycyclohex-1-enecarboxylic acid (DHCHC) as a starter unit, four molecules of malonyl-CoA, five molecules of methylmalonyl-CoA, one molecule of allylmalonyl-CoA as elongation units. However, two molecules of malonyl-CoA are able to be replaced by two molecules of methoxymalonyl CoA. Once two malonyl-CoA molecules are replaced, post-synthase tailoring steps are no longer required where two methoxymalonyl CoA molecules are substituted. The biosynthesis of methoxymalonyl CoA to Acyl Carrier protein is proceeded by five enzymes (fkbG, fkbH, fkbI, fkbJ, and fkbK). Allylmalonyl-CoA is also able to be replaced by propionylmalonyl-CoA.

The starter unit, DHCHC from the chorismic acid is formed by fkbO enzyme and loaded onto CoA-ligase domain (CoL). Then, it proceeds to NADPH dependent reduction(ER). Three enzymes, fkbA,B,C enforce processes from the loading module to the module 10, the last step of PKS 1. fkbB enzyme is responsible of allylmalonyl-CoA synthesis or possibly propionylmalonyl-CoA at C21, which it is an unusual step of general PKS 1. As mentioned, if two methoxymalonyl CoA molecules are substituted for two malonyl-CoA molecules, they will take place in module 7 and 8 (C13 and C15), and fkbA enzyme will enforce this process. After the last step (module 10) of PKS 1, one molecule of L-pipecolic acid formed from L-lysine and catalyzed through fkbL enzyme synthesizes with the molecule from the module 10. The process of L-pipecolic acid synthesis is NRPS enforced by fkbP enzyme. After synthesizing the entire subunits, the molecule is cyclized. After the cyclization, the pre-tacrolimus molecule goes through the post-synthase tailoring steps such as oxidation and S-adenosyl methionine. Particularly fkbM enzyme is responsible of alcohol methylation targeting the alcohol of DHCHC starter unit (Carbon number 31 depicted in brown), and fkbD enzyme is responsible of C9 (depicted in green). After these tailoring steps, the tacrolimus molecule becomes biologically active.{{cite journal | vauthors = Chen D, Zhang L, Pang B, Chen J, Xu Z, Abe I, Liu W | title = FK506 maturation involves a cytochrome p450 protein-catalyzed four-electron C-9 oxidation in parallel with a C-31 O-methylation | journal = Journal of Bacteriology | volume = 195 | issue = 9 | pages = 1931–1939 | date = May 2013 | pmid = 23435975 | pmc = 3624582 | doi = 10.1128/JB.00033-13 }}{{cite journal | vauthors = Mo S, Ban YH, Park JW, Yoo YJ, Yoon YJ | title = Enhanced FK506 production in Streptomyces clavuligerus CKD1119 by engineering the supply of methylmalonyl-CoA precursor | journal = Journal of Industrial Microbiology & Biotechnology | volume = 36 | issue = 12 | pages = 1473–1482 | date = December 2009 | pmid = 19756799 | doi = 10.1007/s10295-009-0635-7 | s2cid = 32967249 | doi-access = free }}

Tacrolimus has been shown to reduce the risk of serious infections while also increasing remission of kidney function in lupus nephritis.{{cite journal | vauthors = Singh JA, Hossain A, Kotb A, Wells G | title = Risk of serious infections with immunosuppressive drugs and glucocorticoids for lupus nephritis: a systematic review and network meta-analysis | journal = BMC Medicine | volume = 14 | issue = 1 | pages = 137 | date = September 2016 | pmid = 27623861 | pmc = 5022202 | doi = 10.1186/s12916-016-0673-8 | doi-access = free }}{{cite journal | vauthors = Singh JA, Hossain A, Kotb A, Wells GA | title = Comparative effectiveness of immunosuppressive drugs and corticosteroids for lupus nephritis: a systematic review and network meta-analysis | journal = Systematic Reviews | volume = 5 | issue = 1 | pages = 155 | date = September 2016 | pmid = 27619512 | pmc = 5020478 | doi = 10.1186/s13643-016-0328-z | doi-access = free }}

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.{{cite journal | vauthors = Baumgart DC, Pintoffl JP, Sturm A, Wiedenmann B, Dignass AU | title = Tacrolimus is safe and effective in patients with severe steroid-refractory or steroid-dependent inflammatory bowel disease--a long-term follow-up | journal = The American Journal of Gastroenterology | volume = 101 | issue = 5 | pages = 1048–1056 | date = May 2006 | pmid = 16573777 | doi = 10.1111/j.1572-0241.2006.00524.x | s2cid = 10233231 }} A 2022 updated Cochrane systematic review found that tacrolimus may be superior to placebo in achieving remission and improvement in UC.{{cite journal | vauthors = Gordon M, Sinopoulou V, Akobeng AK, Pana M, Gasiea R, Moran GW | title = Tacrolimus (FK506) for induction of remission in corticosteroid-refractory ulcerative colitis | journal = The Cochrane Database of Systematic Reviews | volume = 2022 | issue = 4 | pages = CD007216 | date = April 2022 | pmid = 35388476 | pmc = 8987360 | doi = 10.1002/14651858.CD007216.pub2 }}

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• {{cite journal | vauthors = Lv X, Qi J, Zhou M, Shi B, Cai C, Tang Y, Pan T, Han Y | title = Comparative efficacy of 20 graft-versus-host disease prophylaxis therapies for patients after hematopoietic stem-cell transplantation: A multiple-treatments network meta-analysis | journal = Critical Reviews in Oncology/Hematology | volume = 150 | pages = 102944 | date = June 2020 | pmid = 32247246 | doi = 10.1016/j.critrevonc.2020.102944 | s2cid = 214794350 }}

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• {{cite web | title=Tacrolimus Injection | website=MedlinePlus | url=https://medlineplus.gov/druginfo/meds/a608037.html }}
• {{cite web | title=Tacrolimus Topical | website=MedlinePlus | url=https://medlineplus.gov/druginfo/meds/a602020.html }}
• {{MeSH name|Tacrolimus}}
• {{cite web | title=FDA Approves New Use of Transplant Drug Based on Real-World Evidence | website=U.S. Food and Drug Administration (FDA) | date=30 September 2021 | url=https://www.fda.gov/drugs/drug-safety-and-availability/fda-approves-new-use-transplant-drug-based-real-world-evidence }}

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