Mercaptopurine Systematic (IUPAC) name 3,7-dihydropurine-6-thione Clinical data Trade names Purinethol AHFS/Drugs.com MedlinePlus Pregnancy cat. ?,(Increased Risk of Abortion) Legal status ? Routes Oral Pharmacokinetic data Bioavailability 5 to 37% Metabolism xanthine oxidase Half-life 60 to 120 min., longer for its active metabolites Excretion Renal Identifiers CAS number ATC code L01 PubChem DrugBank ChemSpider UNII KEGG ChEBI ChEMBL Chemical data Formula C5H4N4S Mol. mass 152.177 g/mol SMILES & (what is this?)
Mercaptopurine (also called 6-mercaptopurine, 6-MP or its brand name Purinethol) is an immunosuppressive drug.
It is used to treat leukemia, pediatric non-Hodgkin's lymphoma, polycythemia vera, psoriatic arthritis, and inflammatory bowel disease (such as Crohn's disease and ulcerative colitis).
It has demonstrated some in vitro effectiveness against Mycobacterium paratuberculosis.
Mechanisms of action
6-MP ribonucleotide inhibits purine nucleotide synthesis and metabolism. This alters the synthesis and function of RNA and DNA. Mercaptopurine interferes with nucleotide interconversion and glycoprotein synthesis.
Some of the adverse reactions of taking mercaptopurine might include diarrhea, nausea, vomiting, loss of appetite, fatigue, stomach/abdominal pain, weakness, skin rash, darkening of the skin, or hair loss. Serious adverse reactions include mouth sores, fever, sore throat, easy bruising or bleeding, pinpoint red spots on the skin, yellowing of eyes or skin, dark urine, and painful or difficult urination. Unlikely but serious side-effects include: black or tarry stools (melena), bloody stools, and bloody urine.
Mercaptopurine causes myelosuppression, suppressing the production of white blood cells and red blood cells. It may be toxic to bone marrow. Weekly blood counts are recommended for patients on mercaptopurine. The patient should stop taking the medication at least temporarily if there is an unexplained, abnormally large drop in white blood cell count, or any other blood count.
Patients exhibiting myelosuppression or bone marrow toxicity should be tested for thiopurine methyltransferase (TPMT) enzyme deficiency. Patients with TPMT deficiency are much more likely to develop dangerous myelosuppression. In such patients, it may be possible to continue using mercaptopurine, but at a lower dose.
Allopurinol inhibits xanthine oxidase, the enzyme that breaks down mercaptopurine. Those taking allopurinol (often used to prevent gout) are at risk for mercaptopurine toxicity. The dose should be reduced or allopurinol should be discontinued.
Mercaptopurine can lower the body's ability to fight off infection. Those taking mercaptopurine should get permission from a doctor in order to receive immunizations and vaccinations. It is also recommended that, while on the drug, one should avoid those having recently received oral polio vaccine.
This drug is traditionally not recommended during pregnancy, but this issue has been debated, and current evidence indicates that pregnant women on the drug show no increase in fetal abnormalities. However, women receiving mercaptopurine during the first trimester of pregnancy have an increased incidence of miscarriage. Davis et al. 1999 found that mercaptopurine, compared to methotrexate, was ineffective as a single-agent abortifacient; every woman in the mercaptopurine arm of the study had fetal cardiac activity at follow-up (two weeks later) and was given a suction abortion.
Mercaptopurine causes changes to chromosomes in animals and humans, though a study in 1990 found that, "while the carcinogenic potential of 6-MP cannot be precluded, it can be only very weak or marginal." Another study in 1999 noted an increased risk of developing leukemia when taking large doses of 6-MP together with other cytotoxic drugs.
- ^ Sahasranaman S, Howard D, Roy S (August 2008). "Clinical pharmacology and pharmacogenetics of thiopurines". Eur. J. Clin. Pharmacol. 64 (8): 753–67. doi:10.1007/s00228-008-0478-6. ISBN 0022800804786. PMID 18506437.
- ^ Nielsen OH, Vainer B, Rask-Madsen J (November 2001). "Review article: the treatment of inflammatory bowel disease with 6-mercaptopurine or azathioprine". Aliment. Pharmacol. Ther. 15 (11): 1699–708. doi:10.1046/j.1365-2036.2001.01102.x. PMID 11683683. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0269-2813&date=2001&volume=15&issue=11&spage=1699.
- ^ Shin SJ, Collins MT (February 2008). "Thiopurine drugs azathioprine and 6-mercaptopurine inhibit Mycobacterium paratuberculosis growth in vitro". Antimicrob. Agents Chemother. 52 (2): 418–26. doi:10.1128/AAC.00678-07. PMC 2224720. PMID 18070971. http://aac.asm.org/cgi/pmidlookup?view=long&pmid=18070971.
- ^ Nørgård, B.; L. Pedersen, K. Fonager, S. Rasmussen, H. Sørensen (March 2003). "Azathioprine, mercaptopurine and birth outcome: a population-based cohort study". Alimentary pharmacology and therapeutics 17 (6): 827–834. doi:10.1046/j.1365-2036.2003.01537.x. PMID 12641505.
- ^ Davis, Anne R.; Leslie Miller, Hisham Tamimi, and Allen Gown (June 1999). "Methotrexate Compared With Mercaptopurine for Early Induced Abortion". Obstetrics & Gynecology 93 (6): 904–9. doi:10.1016/S0029-7844(98)00569-9. PMID 10362152. http://www.greenjournal.org/cgi/content/full/93/6/904.
- ^ Maekawa, A.; T. Nagaoka, H. Onodera, Y. Matsushima, A. Todate, M. Shibutani, H. Ogasawara, Y. Kodama and Y. Hayashi (May 1990). "Two-year carcinogenicity study of 6-mercaptopurine in F344 rats". Journal of Cancer Research and Clinical Oncology 116 (3): 245–250. doi:10.1007/BF01612898. PMID 2370249. http://www.springerlink.com/content/k28hxj615p761764/.
- ^ Bo J, Schrøder H, Kristinsson J, Madsen B, Szumlanski C, Weinshilboum R, Andersen JB, Schmiegelow K (September 1999). "Possible carcinogenic effect of 6-mercaptopurine on bone marrow stem cells: relation to thiopurine metabolism". Cancer 86 (6): 1080–6. doi:10.1002/(SICI)1097-0142(19990915)86:6<1080::AID-CNCR26>3.0.CO;2-5. PMID 10491537.
Intracellular chemotherapeutic agents/antineoplastic agents (L01) SPs/MIs
(M phase)Block microtubule assemblyBlock microtubule disassembly
inhibitorIIICrosslinking of DNA
(CCNS)Aziridines: Carboquone • ThioTEPA • Triaziquone • Triethylenemelamine
Photosensitizers/PDT OtherOther/ungroupedAmsacrine • Trabectedin • retinoids (Alitretinoin, Tretinoin) • Arsenic trioxide • asparagine depleters (Asparaginase/Pegaspargase) • Celecoxib • Demecolcine • Elesclomol • Elsamitrucin • Etoglucid • Lonidamine • HAMLET (human alpha-lactalbumin made lethal to tumor cells) • Lucanthone • Mitoguazone • Mitotane • Oblimersen • Omacetaxine mepesuccinate • mTOR inhibitors (Everolimus, Temsirolimus)
tumr, epon, para
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mercaptopurine — mer·cap·to·pu·rine (.)mər .kap tə pyu̇(ə)r .ēn n an antimetabolite C5H4N4S that interferes esp. with the metabolism of purine bases and the biosynthesis of nucleic acids and that is sometimes useful in the treatment of acute leukemia * * * n. a… … Medical dictionary
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mercaptopurine — noun Etymology: mercaptan + o + purine Date: circa 1952 an antimetabolite C5H4N4S that interferes especially with the metabolism of purine bases and the biosynthesis of nucleic acids and that is sometimes used in the treatment of acute leukemia … New Collegiate Dictionary
mercaptopurine — /meuhr kap toh pyoor een/, n. Pharm. a yellow, crystalline, water insoluble powder, C5H4N4S, used in the treatment of leukemia. [1950 55; MERCAPTO + PURINE] * * * … Universalium
mercaptopurine — noun A particular oral drug used in the treatment of cancer … Wiktionary
mercaptopurine — n. chemical substance which is used to treat leukemia (Pharmacology) … English contemporary dictionary
mercaptopurine — mer·cap·to·purine … English syllables
mercaptopurine — n. a drug that prevents the growth of cancer cells and is administered by mouth, chiefly in the treatment of some types of leukaemia (see antimetabolite). It commonly reduces the numbers of white blood cells; mouth ulcers and digestive upsets may … The new mediacal dictionary