Description
6‑MP 50 mg (Mercaptopurine) – Maintenance Chemotherapy for ALL & Immune-Mediated Disorders
6‑Mercaptopurine (6‑MP) 50 mg tablets, also sold as Purinethol, is a purine antimetabolite indicated for maintenance therapy in acute lymphoblastic leukemia (ALL) in both adults and pediatric patients. It also finds off-label use in Crohn’s disease and ulcerative colitis remission management.
💊 Dosing & Administration
- Starting dose: 1.5–2.5 mg/kg orally once daily (typically 50–75 mg/m²). Adult induction may use up to 2.5 mg/kg/day.
- Adjust dose for:
- TPMT or NUDT15 deficiency: reduce initial dose dramatically—often to 10% or less.
- Concomitant allopurinol: reduce mercaptopurine dose by ~75%.
- Renal or hepatic impairment: start at lowest end of dose range.
- Take once daily on an empty stomach to ensure consistent absorption.
⚠️ Side Effects & Safety Monitoring
- **Major risk:** bone marrow suppression leading to neutropenia, anemia, thrombocytopenia—requires regular CBC monitoring.
- Other common side effects include nausea, loss of appetite, liver toxicity, skin rash, fatigue; rare risk of pancreatitis or secondary malignancy.
- Pharmacogenetic variants (TPMT, NUDT15) significantly alter toxicity risk—genetic screening can guide safer dosing.
✅ Benefits & Patient Guidance
- Oral therapy supports outpatient maintenance regimens in ALL, avoiding hospitalization.
- Clear guidance for dose adjustments with genetics or interacting drugs helps personalize safety.
- A liquid suspension (Purixan) is available for pediatric dosing flexibility.
❓ Frequently Asked Questions (FAQs)
1. What if I miss a dose?
Skip it and continue with your next scheduled dose. Do not double dose.
2. Should TPMT testing be done?
Yes—knowing TPMT or NUDT15 status helps prevent severe myelosuppression and guides initial dose selection.
3. Can it be used in Crohn’s disease?
Yes—but only off‑label and usually in combination with other immunomodulators; dose often lower (~1.5 mg/kg).
4. How often should labs be checked?
CBC and liver tests should be done weekly during initiation, then periodically based on stability and clinical protocol.
5. Is it safe during pregnancy?
No—it’s teratogenic. Effective contraception is required during and after therapy.
