- FDA Approved (in combination regimens)
- Off-Label Use
- Inflammatory Bowel Disease (Crohns Disease, Ulcerative Colitis)
- Cancer
- Acute promyelocytic Leukemia
- Autoimmune Hepatitis
- Lymphoblastic Lymphoma
- Mercaptopurine is a thiopurine derivative with antineoplastic and Immunosuppressant activity
- Mercaptopurine is a prodrug metabolized to active components by hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
- Metabolites inhibit interconversion between Nucleotides, inhibiting Purine and DNA synthesis
- Metabolites
- 6-thioGMP (6-thioguanosine-5'-phosphate)
- T-IMP (6-thioinosine monophosphate)
- Mercaptopurine is also a metabolized to deoxythioguanosine
- Deoxythioguanosine is a purine Nucleoside antimetabolite analog
- Incorporated into DNA in place of the Nucleoside Guanosine
- Interrupts DNA Replication
- Mercaptopurine is also metabolized to 6-methylmercaptopurine ribonucleoside (MMPR) by 6-thiopurine methyltransferase
- MMPR inhibits Purine synthesis
- Mercaptopurine tablets: 50 mg
- Mercaptopurine oral solution: 20 mg/ml
- See other references for disease specific dosing protocols
- Consider concurrent Folic Acid supplementation
-
Inflammatory Bowel Disease (Crohns Disease, Ulcerative Colitis)
- Start (adult): 50 mg orally daily, then titrate to effect
- Adult and Child Dosing Range: 0.5 to 1.5 mg/kg orally daily
- Dose reduction indications (by >50%)
- Thiopurine methyltransferase (TPMT) Deficiency
- NUDT15 Gene Anomaly (Nudix Hydrolase 15 deficiency)
- Alopecia
- Carcinogenic
- Case reports of T-Cell Lymphoma development after Mercaptopurine
- Myelosuppression
- Hepatotoxicity
- Hyperuricemia
- Hypoglycemia
- Lymphoproliferative Disorder
- Pancreatitis
- Photosensitivity
- Portal Hypertension
- Avoid in Pregnancy (any trimester)
- Use reliable Contraception
- Avoid in Lactation
- Monitoring
- Drugs that increase Mercaptopurine toxicity
- Mercaptopurine (DailyMed)