Generic
Mercaptopurine
3 brands available in the market
At a glance
Mercaptopurine is an anti-cancer medication used for maintenance therapy of acute lymphoblastic leukemia (ALL). It interferes with DNA and RNA formation in cancer cells to stop their growth and division.
Description
Mercaptopurine is a purine antagonist that is converted intracellularly into its active nucleotides, including thioinosinic acid. These nucleotides inhibit several reactions that ultimately interfere with nucleic acid synthesis and prevent the formation of RNA and DNA.
Indications
- Acute lymphoblastic leukemia (ALL) - maintenance therapy (as part of a combination regimen)
- Crohn's disease (off-label)
Therapeutic class
Cytotoxic Chemotherapy
Pharmacological class
Purine Antagonist
Pharmacology
Mercaptopurine is converted intracellularly to active nucleotides that interfere with nucleic acid synthesis and prevent RNA and DNA formation.
Mechanism of action
Interferes with DNA and RNA formation in cancer cells to stop their growth and division.
Dosage
ALL (Adults):
- Induction: 2.5 mg/kg/day (usually 100-200 mg/day)
- Maintenance: 1.5-2.5 mg/kg/day
- Reduce dose by 75% with allopurinol
ALL (Children): 1.25-2.5 mg/kg/day (50-75 mg/m²); Maintenance: 1.5-2.5 mg/kg/day
Crohn's Disease (Adults): Initial 1-1.5 mg/kg/day; max 125 mg/day
Administration
- Swallow tablet whole; do not chew, crush or break
- Take on an empty stomach (1 hour before or 2 hours after food)
- Ensure adequate fluid intake
Missed dose
If you miss a dose, take it as soon as you remember; skip if it's almost time for next dose; do not double the dose.
Side effects
Common Side Effects:
- Nausea, vomiting
- Skin rash
- Decreased white blood cell count (neutrophils)
- Intestinal ulcer
- Anemia
- Increased bilirubin
- Low blood platelets
- Increased transaminases
- Diarrhea, loss of appetite
Precautions & warnings
- Caution in hepatic and renal dysfunction; monitor hepatic function periodically
- Myelosuppression - monitor blood counts regularly
- TPMT deficiency may cause severe myelotoxicity
- Do not use during pregnancy and lactation
- Caution when driving or doing activities requiring concentration (may cause dizziness)
Contraindications
- Pregnancy and lactation
- Prior resistance to mercaptopurine or thioguanine
- Severe liver disease
- Severe bone marrow suppression
Drug interactions
- May inhibit anticoagulant action of warfarin
- Enhanced toxicity with myelosuppressive drugs
- Allopurinol enhances effects (reduce dose)
- Other hepatotoxic drugs (doxorubicin) potentiate toxicity
Food interactions
Safety with alcohol is not known; consult your doctor.
Use in pregnancy
Use in Pregnancy: Mercaptopurine is unsafe during pregnancy (Category D); definite evidence of risk to the fetus. Use only in life-threatening situations with doctor's advice.
Pregnancy Category: D — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Mercaptopurine is probably unsafe during breastfeeding; may pass into breast milk.
Pediatric use
Pediatric doses established (weight and age-based).
Geriatric use
Elderly may require dose adjustment (based on renal and hepatic function).
Renal / hepatic impairment
Renal Impairment: Caution in kidney disease; dose adjustment may be needed.
Hepatic Impairment: Caution in liver disease; dose adjustment may be needed; inform doctor if signs of jaundice occur.
Overdose effects
Overdose may cause myelosuppression, nausea, diarrhea; symptomatic treatment.
Storage conditions
Store at 20-25°C.
Chemical structure
Mercaptopurine