Purinethol

An antimetabolite antineoplastic agent with immunosuppressant properties. It interferes with nucleic acid synthesis by inhibiting purine metabolism and is used, usually in combination with other drugs, in the treatment of or in remission maintenance programs for leukemia. .
[PubChem].

Medicinal name:
  • Mercaptopurine 50 MG Oral Tablet [Purinethol]

Purinethol - Pharmacology:

Purinethol competes with hypoxanthine and guanine for the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) and is itself converted to thioinosinic acid (TIMP). This intracellular nucleotide inhibits several reactions involving inosinic acid (IMP), including the conversion of IMP to xanthylic acid (XMP) and the conversion of IMP to adenylic acid (AMP) via adenylosuccinate (SAMP). In addition, 6-methylthioinosinate (MTIMP) is formed by the methylation of TIMP. Both TIMP and MTIMP have been reported to inhibit glutamine-5-phosphoribosylpyrophosphate amidotransferase, the first enzyme unique to the de novo pathway for purine ribonucleotide synthesis. Experiments indicate that radiolabeled mercaptopurine may be recovered from the DNA in the form of deoxythioguanosine. Some mercaptopurine is converted to nucleotide derivatives of 6-thioguanine (6-TG) by the sequential actions of inosinate (IMP) dehydrogenase and xanthylate (XMP) aminase, converting TIMP to thioguanylic acid (TGMP).

Purinethol for patients

Patients should be informed that the major toxicities of PURINETHOL are related to myelosuppression, hepatotoxicity, and gastrointestinal toxicity. Patients should never be allowed to take the drug without medical supervision and should be advised to consult their physician if they experience fever, sore throat, jaundice, nausea, vomiting, signs of local infection, bleeding from any site, or symptoms suggestive of anemia. Women of childbearing potential should be advised to avoid becoming pregnant.

Purinethol Interactions

When allopurinol and mercaptopurine are administered concomitantly, it is imperative that the dose of mercaptopurine be reduced to one third to one quarter of the usual dose. Failure to observe this dosage reduction will result in a delayed catabolism of mercaptopurine and the strong likelihood of inducing severe toxicity.

There is usually complete cross-resistance between mercaptopurine and thioguanine.

The dosage of mercaptopurine may need to be reduced when this agent is combined with other drugs whose primary or secondary toxicity is myelosuppression. Enhanced marrow suppression has been noted in some patients also receiving trimethoprim-sulfamethoxazole.

Inhibition of the anticoagulant effect of warfarin, when given with mercaptopurine, has been reported.

As there is in vitro evidence that aminosalicylate derivatives (e.g., olsalazine, mesalazine, or sulphasalazine) inhibit the TPMT enzyme, they should be administered with caution to patients receiving concurrent mercaptopurine therapy.

 

 

Purinethol Contraindications

PURINETHOL should not be used unless a diagnosis of acute lymphatic leukemia has been adequately established and the responsible physician is knowledgeable in assessing response to chemotherapy.

PURINETHOL should not be used in patients whose disease has demonstrated prior resistance to this drug. In animals and humans, there is usually complete cross-resistance between mercaptopurine and thioguanine.

PURINETHOL should not be used in patients who have a hypersensitivity to mercaptopurine or any component of the formulation.

Manufacturers name:

  • Gate Pharmaceuticals

Generic name, Overdose, Half Life Purinethol, Food Interactions, Chemical, etc..

Purinethol see also FDA report

Brand Names containing Mercaptopurine

Chemical structure:
N S N H N H N H H C5H4N4S 2D chemical structure C5H4N4S SVG | 2D structure Mercaptopurine chemical names, chemical properties, classification C5H4N4S