Methotrexate

Indications

Rheumatoid Arthritis Psoriasis Cancer Inflammation

Neoplastic Diseases Methotrexate is used in the treatment of gestational choriocarcinoma, chorioadenoma destruens and hydatidiform mole. In acute lymphoblastic leukemia, it is used too. It is also given in combination with other chemotherapeutic agents in the treatment of advanced stage non-Hodgkin's lymphomas. Methotrexate is used in the treatment of breast cancer, epidermoid cancers of the head and neck, advanced mycosis fungoides (cutaneous T-cell lymphoma) and lung cancer, particularly the squamous cell and small cell types. Rheumatoid Arthritis including Polyarticular-Course Juvenile Rheumatoid Arthritis Methotrexate is indicated in the management of selected adults with severe, active rheumatoid arthritis, or children with active polyarticular-course juvenile rheumatoid arthritis. These are patients who have not responded well enough to, or can't tolerate, an adequate trial of first-line therapy, including full dose non-steroidal anti-inflammatory agents (NSAIDs). Psoriasis Methotrexate is indicated for the symptomatic control of severe, recalcitrant, disabling psoriasis that does not respond adequately to other forms of therapy.

⚠️ Always consult a registered physician before taking any medicine.

Pharmacology

Methotrexate works by inhibiting dihydrofolic acid reductase. Normally, this enzyme reduces dihydrofolates to tetrahydrofolates, which the body needs as carriers of one carbon groups when building purine nucleotides and thymidylate. By blocking this step, methotrexate interferes with DNA synthesis, repair, and cell replication. Tissues that proliferate rapidly, such as malignant cells, bone marrow, fetal cells, the lining of the mouth and intestines, and cells of the urinary bladder, tend to be more sensitive to this effect. Because malignant tissue often proliferates faster than most normal tissue, methotrexate can suppress malignant growth without causing irreversible damage to normal tissues. In psoriasis, skin cells are produced at a much faster rate than in normal skin, and it is this heightened rate of proliferation that methotrexate acts on to help control the psoriatic process.

Pregnancy & Breastfeeding

In the United States, the FDA places methotrexate in Pregnancy Category X. This means it should be used for cancer treatment only when the possible benefit clearly outweighs the risk to the unborn baby. Methotrexate is also not to be given to mothers who are breastfeeding.

⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.

Dosage Reference

⚠️ Reference ranges from official sources only. Consult your doctor for personalized dosing.

Adults: Neoplastic diseases. Choriocarcinoma and similar trophoblastic diseases: given orally or intramuscularly in doses of 15 to 30 mg daily for a five-day course. The courses are usually repeated 3 to 5 times as required, with rest periods of one or more weeks interposed between courses, until any manifesting toxic symptoms subside. Since hydatidiform mole may precede choriocarcinoma, prophylactic chemotherapy with methotrexate has been recommended. Chorioadenoma destruens is considered to be an invasive form of hydatidiform mole. Methotrexate is administered in these disease states in doses similar to those recommended for choriocarcinoma. Acute lymphoblastic leukemia. Induction dose: 3.3 mg/m2 in combination with prednisone 60 mg/m2 daily for 4 to 6 weeks. Maintenance dose: given orally or intramuscularly 2 times a week in total weekly doses of 30 mg/m2. Alternate maintenance dose: 2.5 mg/kg intravenously every 14 days. If and when relapse does occur, reinduction of remission can again usually be obtained by repeating the initial induction regimen. Lymphoma. Burkitt's tumor, stages I to II: 10 to 25 mg once a day for 4 to 8 days. Burkitt's tumor, stage III: methotrexate is commonly given concomitantly with other antitumor agents. Duration of therapy: all stages usually require several courses of therapy interposed with 7 to 10 day rest periods. Lymphosarcoma, stage III: 0.625 to 2.5 mg/kg daily as part of combination chemotherapy. Mycosis fungoides. Early stage dosing: 5 to 50 mg once a week; alternatively, 15 to 37.5 mg 2 times a week may be used in patients who have responded poorly to weekly therapy. Breast cancer: 40 mg/m2 intravenously on the 1st and 8th day every 4 weeks in combination with cyclophosphamide and fluoracil for 6 to 12 cycles. Head and neck cancer: 40 mg/m2 intravenously weekly until disease progression or unacceptable toxicity (3 weeks equals one cycle; the goal is to complete at least six cycles). Adult rheumatoid arthritis: single doses of 7.5 mg once per week. Maximum dose: 20 mg/week in adults. Polyarticular-course juvenile rheumatoid arthritis: 10 mg/m2 once weekly. Psoriasis: single dose of 10 to 25 mg once per week. Maximum dose: 30 mg/week.

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Indications

Pharmacology

Pregnancy & Breastfeeding

Dosage Reference

Side Effects & Interactions

Side Effects

Key Interactions