Methotrexate Remedica (Methotrexate)

Methotrexate is an antimetabolite used across several disease families, primarily autoimmune conditions and hematologic cancers.

• Rheumatoid arthritis: reduces joint inflammation and slows disease progression.
• Psoriasis: diminishes skin plaque formation and severity.
• Acute lymphoblastic leukemia: interferes with leukemic cell proliferation.
• Non‑Hodgkin lymphoma: impedes malignant lymphocyte growth.

• Methotrexate inhibits dihydrofolate reductase, blocking the conversion of dihydrofolate to tetrahydrofolate. This limits the synthesis of purine nucleotides and thymidylate, leading to reduced DNA, RNA and protein production, which suppresses rapidly dividing immune cells and malignant cells.

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

Common Side Effects

• Nausea and vomiting: gastrointestinal upset occurring shortly after dosing.
• Fatigue: persistent tiredness not relieved by rest.
• Oral mucositis: painful sores in the mouth.
• Cytopenias: lowered white blood cells, red blood cells or platelets.
• Elevated liver enzymes: mild hepatic enzyme rise on laboratory testing.
• Alopecia: temporary hair thinning or loss.

Serious or Rare Side Effects

• Severe hepatotoxicity: significant liver injury requiring monitoring.
• Pulmonary fibrosis: progressive lung scarring causing breathlessness.
• Life‑threatening bone marrow suppression: profound pancytopenia.
• Renal failure: impaired kidney function affecting drug clearance.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis: severe skin reactions.
• Opportunistic infections: increased susceptibility due to immunosuppression.

Before initiating therapy, clinicians should assess baseline health status and monitor regularly.

• Baseline laboratory testing: obtain complete blood count, liver and renal function tests.
• Folic acid supplementation: consider to reduce mucosal and hematologic toxicity.
• Pregnancy and lactation: avoid use; methotrexate is contraindicated in pregnancy.
• Concomitant nephrotoxic agents: use with caution and monitor renal function.
• Alcohol consumption: limit intake to reduce hepatic risk.
• Store at ambient temperature: keep below 25 °C, in the original container, protected from moisture and direct sunlight.

Methotrexate interacts with several drug classes that can alter its efficacy or safety.

Major Interactions (Avoid)

• Non‑steroidal anti‑inflammatory drugs (NSAIDs): increase methotrexate toxicity.
• Penicillins and sulfonamides: may potentiate bone marrow suppression.
• Live vaccines: heightened risk of infection due to immunosuppression.
• Alcohol: synergistic hepatotoxic effect.
• High‑dose folic acid: may reduce therapeutic effect.

Moderate Interactions (Monitor Closely)

• Proton pump inhibitors: can raise methotrexate plasma levels.
• Diuretics: affect renal clearance, requiring dose adjustment.
• Warfarin: may enhance anticoagulant effect, monitor INR.
• Azathioprine: additive immunosuppression, watch for infections.
• Vitamin B12: may interfere with folate pathways, monitor blood counts.