Class/mechanism: Purine analog of adenine and hypoxanthine, antimetabolite that interferes with DNA synthesis. Mercaptopurine competes with hypoxanthine and guanine for the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) and is converted to thioinosinic acid (TIMP). TIMP inhibits reactions that typically involve inosinic acid (IMP), such as its conversion to xanthylic acid (XMP) and adenylic acid (AMP) via adenylosuccinate (SAMP). TIMP is also converted to 6-methylthioinosinate (MTIMP); TIMP and MTIMP have been observed to inhibit glutamine-5-phosphoribosylpyrophosphate amidotransferase, which is an early enzyme in the de novo pathway of purine ribonucleotide synthesis. Mercaptopurine is structurally and functionally similar to Thioguanine (Tabloid).
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Diseases for which it is used
Patient drug information
History of changes in FDA indication
- 9/11/1953: Initial FDA approval
- 4/28/2014: Purixan (mercaptopurine oral suspension formulation) FDA approved
- As of most recent package insert: indicated for maintenance therapy of acute lymphatic (lymphocytic, lymphoblastic) leukemia as part of a combination regimen. The response to this agent depends upon the particular subclassification of acute lymphatic leukemia and the age of the patient (pediatric or adult).
Also known as
- Generic names: 6-MP, 6-Mercaptopurine
- Brand names: Purinethol, Purixan (oral suspension formulation)
- Mercaptopurine (Purinethol) package insert
- Mercaptopurine (Purinethol) package insert (locally hosted backup)
- Mercaptopurine (Purixan) package insert
- Mercaptopurine (Purixan) package insert (locally hosted backup)
- Mercaptopurine (Purinethol) patient drug information (Chemocare)
- Mercaptopurine (Purinethol) patient drug information (UpToDate)