Nordimet (Methotrexate)

Methotrexate is indicated for several autoimmune and oncologic conditions, where it modulates immune activity and inhibits malignant cell growth, providing therapeutic benefit across multiple disease states.

• Rheumatoid arthritis: reduces joint inflammation, pain, and slows structural damage progression, improving functional capacity.
• Psoriasis: decreases plaque formation and severity of skin lesions, reducing itching and improving quality of life.
• Acute lymphoblastic leukemia: interferes with malignant lymphoblast replication, contributing to remission when used in chemotherapy protocols.
• Non‑Hodgkin lymphoma: suppresses lymphoma cell proliferation as part of combination regimens, aiding disease control.

• Methotrexate exerts its pharmacologic effect by competitively inhibiting the enzyme dihydrofolate reductase, which is required for the conversion of dihydrofolate to tetrahydrofolate. This blockade reduces the availability of tetrahydrofolate for purine and pyrimidine synthesis, leading to decreased DNA, RNA and protein production. The resulting inhibition of cell proliferation particularly affects rapidly dividing immune cells and malignant cells, providing immunosuppressive and antineoplastic activity.

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

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset, often transient.
• Fatigue: persistent feeling of tiredness or reduced energy.
• Mouth ulcers: painful sores in the oral mucosa that may affect eating.
• Elevated liver enzymes: mild increases in hepatic transaminases detectable on labs.

Serious or Rare Side Effects

• Bone marrow suppression: can lead to anemia, leukopenia, or thrombocytopenia, increasing infection and bleeding risk.
• Pulmonary toxicity: interstitial pneumonitis presenting with cough, dyspnea, and fever, requiring prompt evaluation.
• Severe hepatotoxicity: risk of liver fibrosis or cirrhosis with long‑term therapy, necessitating regular monitoring.

Before initiating therapy with Methotrexate, several precautions should be observed to minimize risk.

• Baseline testing: obtain complete blood count, liver and renal function tests prior to treatment.
• Pregnancy contraindication: avoid use in pregnancy due to known teratogenic effects (Category X).
• Contraception requirement: ensure effective contraception for both men and women of reproductive potential during therapy.
• Renal impairment: assess kidney function and adjust or avoid use in patients with significant renal dysfunction.
• Regular monitoring: schedule periodic laboratory evaluations to detect hematologic or hepatic changes.
• Store at ambient temperature: keep in original packaging, protect from moisture and light.

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

Major Interactions (Avoid)

• Non‑steroidal anti‑inflammatory drugs (NSAIDs): may reduce renal clearance and raise methotrexate levels, increasing toxicity.
• Proton pump inhibitors (e.g., omeprazole): can elevate plasma concentrations of methotrexate.
• Trimethoprim‑sulfamethoxazole: enhances risk of bone marrow suppression when combined with methotrexate.

Moderate Interactions (Monitor Closely)

• Live vaccines: reduced efficacy and heightened infection risk; avoid during treatment.
• Other immunosuppressants (e.g., azathioprine): additive immunosuppression may increase infection susceptibility.
• Folate supplements: may diminish therapeutic effect while alleviating toxicity; dose adjustments should be guided by a clinician.