Methotrexate Afortas (Methotrexate)

Methotrexate acts on the folate pathway and is indicated for several immune‑mediated and oncologic conditions.

• Rheumatoid arthritis: reduces joint inflammation and slows disease progression.
• Psoriasis: diminishes skin plaque formation and severity.
• Acute lymphoblastic leukemia: interferes with malignant cell proliferation.
• Non‑Hodgkin lymphoma: contributes to tumor control as part of combination therapy.
• Breast cancer: used in certain protocols to inhibit tumor growth.

• Methotrexate inhibits the enzyme dihydrofolate reductase, preventing the conversion of dihydrofolate to tetrahydrofolate. This blocks the synthesis of purine nucleotides and thymidylate, impairing DNA, RNA and protein production, which limits the proliferation of rapidly dividing cells, including immune cells and cancer cells.

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

Common Side Effects

• Nausea or vomiting.
• Fatigue or malaise.
• Oral mucosal ulceration (mouth sores).
• Mild elevation of liver enzymes.
• Transient low white blood cell count.
• Hair thinning or loss.

Serious or Rare Side Effects

• Severe liver toxicity or fibrosis.
• Pulmonary fibrosis or interstitial pneumonitis.
• Significant bone marrow suppression leading to anemia, neutropenia or thrombocytopenia.
• Acute renal failure.
• Life‑threatening infections due to immunosuppression.
• Rare cutaneous reactions such as Stevens‑Johnson syndrome.

Before initiating therapy, careful monitoring and patient education are essential.

• Liver function monitoring: perform baseline and periodic liver enzyme tests.
• Hematologic monitoring: check complete blood counts regularly.
• Avoid alcohol: concurrent use can increase hepatotoxic risk.
• Contraception requirement: use effective contraception during treatment and for at least three months after cessation.
• Pregnancy contraindication: methotrexate is teratogenic (Category X) and must not be used in pregnant women.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Methotrexate has several drug interactions that may alter its safety or efficacy.

Major Interactions (Avoid)

• NSAIDs (e.g., ibuprofen, naproxen): increase methotrexate toxicity by reducing renal clearance.
• Trimethoprim‑sulfamethoxazole: potentiates myelosuppression.
• Live vaccines: risk of severe infection due to immunosuppression.
• Proton pump inhibitors (high dose): may raise methotrexate plasma levels.

Moderate Interactions (Monitor Closely)

• Phenytoin: may reduce methotrexate effectiveness.
• Azathioprine or other immunosuppressants: additive bone‑marrow suppression.
• Vitamin supplements containing folic acid: can diminish therapeutic effect, requiring dose adjustment.