Mercaptopurina Accord (Mercaptopurine Monohydrate)

Mercaptopurine is used in hematologic malignancies and inflammatory bowel disorders, acting as a purine synthesis inhibitor.

• Acute lymphoblastic leukemia (ALL): helps achieve remission by inhibiting proliferation of lymphoblasts.
• Crohn's disease: reduces intestinal inflammation and supports maintenance of remission.
• Ulcerative colitis: controls disease activity and promotes mucosal healing.

• Mercaptopurine is converted intracellularly to thio‑inosine monophosphate, which blocks de novo purine synthesis and incorporates into DNA and RNA. This interferes with nucleic acid formation, leading to cytotoxicity in rapidly dividing cells such as malignant lymphoblasts and activated immune cells, thereby exerting antineoplastic and immunosuppressive effects.

Mercaptopurine may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Vomiting: occasional episodes after dosing.
• Loss of appetite: reduced desire to eat.
• Mild leukopenia: slight decrease in white blood cells.
• Rash: skin irritation or mild eruption.
• Fatigue: general tiredness.

Serious or Rare Side Effects

• Severe bone marrow suppression: profound pancytopenia.
• Hepatotoxicity: elevated liver enzymes or liver injury.
• Pancreatitis: inflammation of the pancreas.
• Severe infections: opportunistic bacterial or fungal infections.
• Hypersensitivity reactions: anaphylaxis or severe skin reactions.
• Secondary malignancies: rare development of other cancers.

When prescribing Mercaptopurine, clinicians should observe several precautionary measures to minimize risk.

• Monitor blood counts: perform regular CBC to detect myelosuppression.
• Assess liver function: check hepatic enzymes before and during therapy.
• Adjust dose in renal/hepatic impairment: reduce dosage based on organ function.
• Avoid use in pregnancy unless benefits outweigh risks: discuss with obstetric specialist.
• Counsel patients on infection signs: advise immediate medical attention for fever or sore throat.
• Store at room temperature: keep in the original pack, protect from moisture.

Mercaptopurine interacts with several medicines that can alter its efficacy or toxicity.

Major Interactions (Avoid)

• Allopurinol: markedly increases mercaptopurine toxicity.
• Azathioprine: additive myelosuppressive effect.
• Warfarin: enhanced anticoagulant activity.

Moderate Interactions (Monitor Closely)

• NSAIDs: may increase gastrointestinal irritation.
• ACE inhibitors: potential renal function impact.
• Live vaccines: risk of infection due to immunosuppression.