Mercaptopurine
Mercaptopurine is a purine analog antimetabolite primarily used in the treatment of acute lymphoblastic leukemia, particularly during the maintenance phase. It works by converting to active metabolites called thioguanine nucleotides (TGNs) that incorporate into DNA and RNA, disrupting cell division and causing cell death in rapidly dividing cells.
A chemotherapy agent that inhibits DNA/RNA synthesis by converting to toxic metabolites, primarily used to treat certain leukemias.
Key facts at a glance
- ATC
- L01BB02
- RxNorm
- 103
- Generic
- Mercaptopurine
- Class
- atc-l01
- Brands
- Purixan
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- suspension, tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
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Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Primarily used for acute lymphoblastic leukemia (ALL), especially in maintenance therapy. May also be used for other hematologic malignancies and occasionally for autoimmune conditions such as inflammatory bowel disease when used off-label.
As a purine analog, mercaptopurine undergoes intracellular activation to form thioguanine nucleotides (TGNs) and other metabolites. These metabolites incorporate into DNA and RNA during cell replication, causing strand breaks, disrupting normal nucleic acid synthesis, and ultimately leading to cell-cycle arrest and apoptosis in rapidly dividing cells.
Requires regular blood count monitoring due to risk of bone marrow suppression. Has significant drug interactions with allopurinol (requires dose reduction). Contraindicated in pregnancy due to teratogenic potential. May increase risk of infections and secondary malignancies. Patients should avoid live vaccines during treatment.
Official drug label
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This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy