Methotrexate (MTX)

General information

Class/mechanism: Folate analog, antimetabolite, interferes with DNA synthesis. Methotrexate inhibits dihydrofolic acid reductase, which catalyzes reactions that produce tetrahydrofolates, which are used in purine nucleotide and thymidylate synthesis.
Route: IV, PO, IM, IT, SC, intraarterial
Extravasation: inflammitant

For conciseness and simplicity, HemOnc.org currently will focus on treatment regimens and not list information such as: renal/hepatic dose adjustments, metabolism (including CYP450), excretion, monitoring parameters (although this will be considered for checklists), or manufacturer. Instead, for the most current information, please refer to your preferred pharmacopeias such as Micromedex, Lexicomp, UpToDate (courtesy of Lexicomp), or the prescribing information.

Toxicity

Monitoring of plasma levels

1. Stoller RG, Hande KR, Jacobs SA, Rosenberg SA, Chabner BA. Use of plasma pharmacokinetics to predict and prevent methotrexate toxicity. N Engl J Med. 1977 Sep 22;297(12):630-4. link to original article PubMed

Reversal agents

• Glucarpidase (Voraxaze) can be used to treat toxic plasma methotrexate concentrations (greater than 1 micromole per liter) in patients with delayed methotrexate clearance due to impaired renal function

Diseases for which it is used

• Acute promyelocytic leukemia
• Adult T-cell leukemia-lymphoma
• B-cell acute lymphoblastic leukemia
• Bladder cancer
• Breast cancer
• Burkitt lymphoma
• CNS leukemia
• CNS lymphoma
• Cutaneous T-cell lymphoma
• Diffuse large B-cell lymphoma
• Extranodal NK- and T-cell lymphoma, nasal type
• Gestational trophoblastic neoplasia
• Head and neck cancer
• Hemophagocytic lymphohistiocytosis
• HIV-associated lymphoma
• Langerhans cell histiocytosis
• Large granular lymphocytic leukemia
• Mantle cell lymphoma
• Medulloblastoma
• NK/T-cell lymphoma
• Osteosarcoma
• Penile cancer
• Peripheral T-cell lymphoma
• Prostate cancer
• Small cell lung cancer
• T-cell acute lymphoblastic leukemia

Patient drug information

• Methotrexate (Otrexup) subcutaneous injection package insert
• Methotrexate (MTX) patient drug information (Chemocare)
• Methotrexate (MTX) patient drug information (UpToDate)

History of changes in FDA indication

• 12/7/1953: Initial FDA approval

Also known as

• Generic names: amethopterin, MTX
• Brand names:

Synonyms
Abitrexate	Alltrex	Antifolan	Artrait	Biometrox	Biotrexate	Caditrex	Cytotrexate
Ebetrexat	Emthexat	Emthexate	Ervemin	Farmitrexat	Fauldmetro	Folex PFS	Folitrax
Hextrate	Ifamet	Imutrex	Ledertrexate	Ledertrexato	Lumexon	Matrex	Maxtrex
Medsatrexate	Merex	Metex	Methobax	Methoblastin	Methorex	Methotrexaat	Methotrexat
Methotrexato	Methotrexatum	Meticil	Metolate	Metotressato	Metotrexate	Metotrexato	Metotrexol
Metrex	Metrexan	Metrexato	Metrotex	Mexate	Miantrex CS	Neometho	Neotrexate
Novatrex	Oncotrex	O Trexat	Pharmatrexate	Remtrex	Reumatrex	Rextop	Rheumatrex
Tecnomet	Texate	Texorate	Tratoben	Tremetex	Trexall	Trexan	Trexeron
Trixilem	Unitrexate	Zexate