Methotrexate (MTX)

•  Mechanism of Action: Folic acid antagonist: acts at catalytic side of dihydrofolate reductase

  • Polyglutamate: important in methotrexate action

  • Tumor resistance to methotrexate: several mechanisms

•  Adverse effects:

  • Bone marrow suppression

  • Dermatologic

  • GI mucosa

  • Adverse effects reversed by leucovorin (citrovorum factor)

    • Leucovorin "rescue" may be used in cases of over dosage or in high-those methotrexate protocols

• Other uses:

  • Treatment of rheumatoid arthritis

  • In combination with a prostaglandin: induces abortion