Mtx-Ratiopharm Teva (Methotrexate)

Methotrexate is used across several disease categories where inhibition of cell proliferation is therapeutic.

• Rheumatoid arthritis: reduces joint inflammation and slows disease progression.
• Psoriasis: decreases skin cell turnover and improves plaque lesions.
• Acute lymphoblastic leukemia: eradicates rapidly dividing leukemic cells as part of chemotherapy protocols.
• Non‑Hodgkin lymphoma: contributes to tumor regression in combination regimens.
• Ectopic pregnancy: terminates trophoblastic tissue when surgical management is not chosen.

• Methotrexate competitively inhibits dihydrofolate reductase, preventing the conversion of dihydrofolate to tetrahydrofolate. This blocks the synthesis of purine nucleotides and thymidylate, impairing DNA, RNA and protein synthesis in rapidly dividing cells. The resulting antiproliferative effect underlies its immunomodulatory activity in rheumatic diseases and its cytotoxic action in malignant neoplasms.

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

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Fatigue: general tiredness or weakness.
• Oral ulceration: sore mouth or tongue.
• Elevated liver enzymes: mild transaminase increase.
• Low blood counts: mild leukopenia or anemia.

Serious or Rare Side Effects

• Severe hepatotoxicity: significant liver injury or fibrosis.
• Pulmonary toxicity: interstitial pneumonitis or fibrosis.
• Bone marrow suppression: profound pancytopenia.
• Renal impairment: acute kidney injury.
• Severe cutaneous reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.

When prescribing methotrexate, clinicians should observe several safety measures to minimize risks.

• Baseline testing: obtain liver function, renal function, and complete blood count before initiation.
• Monitoring: repeat laboratory tests regularly to detect hepatotoxicity or myelosuppression.
• Contraindications: avoid use in pregnancy, breastfeeding, or in patients with severe hepatic disease.
• Drug interactions: review concomitant medications that may increase toxicity, such as NSAIDs or penicillins.
• Patient education: advise on folic acid supplementation and signs of infection or bleeding.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

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

Major Interactions (Avoid)

• Non‑steroidal anti‑inflammatory drugs (NSAIDs): can increase methotrexate plasma levels and risk renal toxicity.
• Proton pump inhibitors (e.g., omeprazole): may reduce renal clearance, heightening toxicity.
• Trimethoprim‑sulfamethoxazole: potentiates myelosuppression.

Moderate Interactions (Monitor Closely)

• Penicillins (e.g., ampicillin): may decrease renal excretion, requiring dose adjustment.
• Azathioprine: additive immunosuppression may increase infection risk.
• Live vaccines: reduced efficacy and potential for infection; avoid concurrent use.