Methotrexate Teva (Methotrexate)

Methotrexate is used across several disease families, primarily autoimmune disorders and certain cancers, by interfering with folate metabolism.

• Rheumatoid arthritis: reduces joint inflammation and slows disease progression.
• Psoriasis: diminishes skin cell proliferation and improves plaque severity.
• Acute lymphoblastic leukemia: inhibits malignant lymphoblast growth and induces remission.
• Non‑Hodgkin lymphoma: impairs tumor cell replication leading to disease control.
• Breast cancer: used as part of combination regimens to limit tumor expansion.
• Osteosarcoma: contributes to tumor shrinkage when combined with other chemotherapeutics.

• Methotrexate acts as a folate antagonist by competitively inhibiting dihydrofolate reductase, which reduces the conversion of dihydrofolate to tetrahydrofolate. The resulting depletion of tetrahydrofolate limits the synthesis of purine nucleotides and thymidylate, impairing DNA, RNA and protein synthesis in rapidly dividing cells. This antiproliferative effect underlies its activity in both malignant and inflammatory conditions.

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

Common Side Effects

• Nausea or vomiting: gastrointestinal upset commonly reported.
• Fatigue: persistent tiredness or weakness.
• Mouth sores: ulceration of oral mucosa.
• Elevated liver enzymes: mild hepatic enzyme rise detectable in labs.
• Diarrhea: loose stools.
• Hair loss: thinning or alopecia.

Serious or Rare Side Effects

• Bone marrow suppression: can lead to anemia, leukopenia or thrombocytopenia.
• Pulmonary toxicity: interstitial pneumonitis presenting with cough and dyspnea.
• Severe hepatotoxicity: risk of fibrosis or cirrhosis with prolonged use.
• Renal toxicity: impaired kidney function.

When using Methotrexate, several precautions should be observed to minimize risks.

• Baseline testing: obtain complete blood count, liver and renal function before therapy.
• Monitoring: perform regular laboratory assessments to detect hematologic or hepatic changes.
• Pregnancy avoidance: drug is contraindicated in pregnancy; effective contraception required for women of childbearing potential.
• Drug interactions: review concomitant medications for potential additive toxicity, especially NSAIDs and sulfonamides.
• Dose adjustments: modify dosage in patients with renal impairment or hepatic disease.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Methotrexate interacts with several medicines; some combinations must be avoided while others require close monitoring.

Major Interactions (Avoid)

• Non‑steroidal anti‑inflammatory drugs (NSAIDs): increase risk of renal toxicity and elevated methotrexate levels.
• Proton pump inhibitors (e.g., omeprazole): may reduce renal clearance, raising systemic exposure.
• Trimethoprim‑sulfamethoxazole: potentiates bone marrow suppression.
• Live vaccines: heightened risk of infection due to immunosuppression.

Moderate Interactions (Monitor Closely)

• Azathioprine or other immunosuppressants: may enhance myelosuppression, monitor blood counts.
• Penicillins (high‑dose): can reduce renal excretion, check serum levels.
• Vitamin supplements containing folic acid: may diminish therapeutic effect, adjust dosing under supervision.