• Acute lymphoblastic leukemia (ALL) (with other agents)

Unlabeled Use:

• Treatment of:
  • Some lymphomas,
  • Polycythemia vera,
  • Crohn's disease,
  • Psoriatic arthritis.

Contraindicated in:

• Hypersensitivity
• Severe hepatic impairment
• OB: Pregnancy (may cause fetal harm)
• Lactation: Lactation.

Use Cautiously in:

• Infections
• ↓bone marrow reserve
• Patients with homozygous TPMT enzyme deficiency or nucleotide diphosphatase (NUDT15) deficiency (substantial dose ↓ are required to avoid hematologic adverse events)
• Rep: Women of reproductive potential
• Geri: ↑risk of adverse reactions.

CNS: weakness.

Derm: alopecia, hyperpigmentation.

Endo: gonadal suppression, oligospermia.

GI: HEPATOTOXICITY, anorexia, diarrhea, nausea, vomiting.

Hemat: MACROPHAGE ACTIVATION SYNDROME, anemia, leukopenia, thrombocytopenia.

Metab: hyperuricemia.

Misc: HEPATOSPLENIC T-CELL LYMPHOMA, SECONDARY MALIGNANCY, fever.

Drug-Drug:

• Allopurinol↓ metabolism and ↑ risk of toxicity from mercaptopurine (↓ dose of mercaptopurine to 25–33% of the usual dose).
• A similar effect may occur with olsalazine sulfasalazine andmesalamine.
• May ↑ risk of bleeding with warfarin.
• ↑risk of hepatotoxicity with other hepatotoxic agents.
• ↑bone marrow depression with trimethoprim/sulfamethoxazole, other antineoplastics, or radiation therapy.
• May alter the effect of warfarin.
• ↓antibody response to live-virus vaccines and ↑ risk of adverse reactions.

Drug-Natural Products:

• Concomitant use with echinacea and melatonin may interfere with immunosuppression.

(Generic available)

• Tablets: 50 mg;
• Oral suspension (raspberry flavor): 20 mg/mL;

• PO (Adults): 1.5–2.5 mg/kg/day as a single dose.
• PO (Children): 2.5 mg/kg/day (75 mg/m²) single dose or divided doses (dose should be rounded to the nearest 25 mg).

Purinethol, Purixan

• Disrupts DNA and RNA synthesis (cell-cycle S phase–specific).

• Death of rapidly proliferating cells, especially malignant ones.
• Also has immunosuppressant properties.

Therapeutic Classification: antineoplastics

Pharmacologic Classification: antimetabolites

Absorption: Variably and incompletely (5–50%) absorbed after oral administration.

Distribution: Widely distributed throughout total body water.

Metabolism/Excretion: Metabolized by liver. Converted to inactive metabolite by thiopurine methyltransferase (TPMT); nucleotide diphosphatase [NUDT15] is also involved in inactivation process. Nearly 50% is excreted unchanged by the kidneys.

Half-life: Three phases — 45 min, 2.5 hr, 10 hr.

(effects on blood counts)

• Instruct patient to take medication as directed. If a dose is missed, omit and take next dose as scheduled; do not double dose.
• Instruct patient to notify health care professional promptly if fever; chills; cough; hoarseness; sore throat; signs of infection; lower back or side pain; painful or difficult urination; bleeding gums; bruising; petechiae; blood in stools, urine, or emesis; increased fatigue; dyspnea; or orthostatic hypotension occurs. Caution patient to avoid crowds and persons with known infections. Instruct patient to use soft toothbrush and electric razor and to avoid falls. Caution patient not to drink alcoholic beverages or take medication containing aspirin or NSAIDs; may precipitate gastric bleeding.
• Instruct patient to report yellowing of anorexia, diarrhea, jaundice, ascites, skin or eyes, dark-colored urine, clay-colored stools, abdominal pain, flank or joint pain, or swelling of feet or legs to health care professional promptly.
• Instruct patient not to receive any vaccinations without advice of health care professional.
• Rep: May cause fetal harm. Advise females of reproductive potential to use effective contraception during therapy and for at least 6 mo after last dose and to avoid breastfeeding during and for 1 wk after last dose of therapy. Advise males with female partners of reproductive potential to use effective contraception during and for 3 mo after last dose. May impair male and female fertility.
• Emphasize the need for periodic lab tests to monitor for side effects.

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NDC Code^*

• 0054- West-Ward Pharmaceuticals Corp.
  • 0054-4581- Mercaptopurine
    • 0054-4581-11- 25 TABLET in 1 BOTTLE, PLASTIC (0054-4581-11)

• 0054- West-Ward Pharmaceuticals Corp.
  • 0054-4581- Mercaptopurine
    • 0054-4581-27- 250 TABLET in 1 BOTTLE, PLASTIC (0054-4581-27)

• 0378- Mylan Pharmaceuticals Inc.
  • 0378-3547- Mercaptopurine
    • 0378-3547-25- 250 TABLET in 1 BOTTLE, PLASTIC (0378-3547-25)

• 0378- Mylan Pharmaceuticals Inc.
  • 0378-3547- Mercaptopurine
    • 0378-3547-52- 25 TABLET in 1 BOTTLE, PLASTIC (0378-3547-52)

• 69076- Quinn Pharmaceuticals, LLC
  • 69076-913- Mercaptopurine
    • 69076-913-02- 25 TABLET in 1 BOTTLE, PLASTIC (69076-913-02)

• 69076- Quinn Pharmaceuticals, LLC
  • 69076-913- Mercaptopurine
    • 69076-913-25- 250 TABLET in 1 BOTTLE, PLASTIC (69076-913-25)