Methotrexate Health Article

Definition

Methotrexate is a folic acid derivative that interferes with folic acid metabolism (folate antagonist). It is a cytotoxic agent (a chemical that is directly toxic to cells) with multiple characteristics and may be described as an antimetabolite, antineoplastic, and immunosuppressant. In the United States, methotrexate is also recognized by the trade names Folex and Mexate, or the generic name amethopterin.

Purpose

Methotrexate is administered to cancer patients diagnosed with various malignancies. These conditions may include breast cancer, lung cancer, non-metastatic bone cancer, cancers associated with the head and neck, acute lymphocytic leukemia, meningeal leukemia, advanced non-Hodgkin's lymphomas, and uterine tumors. Certain other cancers may be treated with methotrexate as prescribed by the oncologist.

Description

Methotrexate was granted FDA approval in 1986. Methotrexate is a highly effective chemical compound that targets a specific enzyme required by cells for normal function. When this enzyme activity is blocked by methotrexate, certain processes within the cell are shut down and cell death results. The growth of some normal cells may be affected by methotrexate. However, because this is a process associated with actively dividing cells, the accelerated rate at which cancer cells grow and divide make them more susceptible to the effects of methotrexate. Methotrexate may be given as a single agent, often followed by leucovorin rescue. Methotrexate may also be administered in a combination regimen with steroids to produce and maintain rapid remission of certain cancers or as part of an adjuvant therapy regimen with doxorubicin, cisplatin, or the BCD combination of bleomycin, cyclophosphamide, and dactinomycin.

Recommended dosage

Methotrexate is available is both injectable and tablet form. The injectable form may be given intravenously (IV), intramuscularly (IM), or intrathecal (directly into the spinal fluid). The dose amount varies over a wide range for patients receiving methotrexate. The final dose and treatment cycle will be determined by the oncologist based on what the medication is being used for, what cancer type is being treated, whether methotrexate is being used as a single agent or in concert with other anticancer drugs, and the method by which the medication is being administered. It is extremely important to take methotrexate in the correct timetable prescribed by the oncologist. If a dose is missed, the patient should not take the missed dose at a later time, or double the next prescribed dose. Rather, the patient should maintain the schedule prescribed and notify the oncologist about the missed dose.