- Acute Lymphoblastic Leukemia (ALL):
- Maintenance therapy in combination with other chemotherapy agents
- Also used in initial treatment phases
- Off-label:
- Inflammatory Bowel Disease (IBD) — especially Crohn’s disease and ulcerative colitis
Dose:1.5 to 2.5 mg/kg/day orally
Note: TPMT or NUDT15 genetic testing may guide dosing to reduce toxicity risk
- PO:50 mg
- Oral Suspension (available in some regions):20 mg/mL
- Take orally once daily
- Take at the same time every day
- Can be taken with or without food, but stay consistent
- Do not crush or chew the tablet
- Monitor CBCs and liver function regularly
- Class: Purine antimetabolite, antineoplastic
- Mechanism of Action:
- Mercaptopurine interferes with DNA and RNA synthesis by mimicking purine bases
- Inhibits proliferation of rapidly dividing cells, particularly leukemic cells
- Pharmacokinetics:
- Metabolism: Liver (via TPMT and xanthine oxidase)
- Half-life: ~1 hour (but intracellular metabolites persist longer)
- Excretion: Renal (as inactive metabolites)
- Bone marrow suppression (↓ WBC, RBC, platelets)
- Nausea, vomiting
- Anorexia
- Diarrhea
- Fatigue
- Hypersensitivity to mercaptopurine
- Concurrent use with febuxostat (xanthine oxidase inhibitor — ↑ risk of toxicity)
- Severe hepatic impairment (relative contraindication)
- Allopurinol (xanthine oxidase inhibitor):
- ↓ Mercaptopurine dose to 25–33% of usual to avoid toxicity
- Febuxostat: Contraindicated
- Warfarin: May decrease anticoagulant effect
- Live vaccines: Avoid due to immunosuppression
Drug Status
Availability | |
Pregnancy | |
Breastfeeding | |
Schedule |
BRAND NAME | STRENGTH | FORMULATION | PACK SIZE | MANUFACTURER | DISTRIBUTOR |
---|---|---|---|---|---|
Purinethol | 50mg | Tablet | 25’s | Aspen Pharmacare | Beta Healthcare |