methotrexate GENERIC NAME: methotrexate BRAND NAMES: Rheumatrex, Trexall DRUG CLASS AND MECHANISM: Methotrexate is classified as an antimetabolite drug, which means it is capable of blocking the metabolism of cells. As a result of this effect, it has been found helpful in treating certain diseases associated with abnormally rapid cell growth, such as cancer of the breast and psoriasis. Recently, methotrexate has been shown to be effective in inducing miscarriage, for example in patients with ectopic pregnancy. This effect of methotrexate is attributed to its action of killing the rapidly growing cells of the placenta. It has also been found very helpful in treating rheumatoid arthritis, although its mechanism of action in this illness is not known. It seems to work, in part by altering aspects of immune function which may play a role in causing rheumatoid arthritis. PRESCRIPTION: yes GENERIC AVAILABLE: yes PREPARATIONS: Injectable: 25mg/ml; Tablet: 2.5mg (Rheumatrex), and 5, 7.5, 10 and 15 mg (Trexall). STORAGE: Store between 59 and 77degrees F in a sealed container, avoid light. PRESCRIBED FOR: Methotrexate is used for cancer treatment generally in higher doses than for other uses, and is often administered intravenously or intramuscularly. Methotrexate is used to treat psoriasis, an inflammatory skin disease, as well as the arthritis that occurs in 10 percent of these patients (psoriatic arthritis). It is also used to treat active rheumatoid arthritis in adults and children. It is also used to treat other rheumatic diseases, including polymyositis and systemic lupus erythematosus. Methotrexate has been used to induce miscarriage in patients with ectopic pregnancy. DOSING: May be taken with or without food. For rheumatoid arthritis and psoriasis, the dose of methotrexate is given WEEKLY, whether by injection or orally. For psoriasis, the weekly dose is often divided into three doses given at 12 hour intervals each week. This has been shown to be more effective, as it relates to the natural growth cycling of the skin. DRUG INTERACTIONS: Because methotrexate can cause serious liver disease, patients with alcoholism or liver disease should not receive it. Patients should curtail alcohol consumption while taking methotrexate. Methotrexate can suppress the body's immunity. Therefore, any symptoms of infection should be reported to the doctor. Patients with underlying immune deficiency diseases should not receive methotrexate. A dry, non-productive cough can be a result of a rare lung toxicity. Methotrexate can impair fertility, decrease sperm count and cause menstrual dysfunction. Safety and effectiveness has not been established in children. PREGNANCY: Methotrexate should not be used in pregnancy, as it can be toxic to the embryo and can cause fetal defects and spontaneous abortion (miscarriage). It should be discontinued prior to conception if used in either partner. Male patients should stop taking methotrexate at least 3 months prior to a planned conception and females should discontinue use for at least one ovulatory cycle before conception. SIDE EFFECTS: Methotrexate can be well tolerated, but also can cause severe toxicity which is usually related to the dose taken. The most frequent reactions include mouth sores, stomach upset, and low white blood counts. Methotrexate can cause severe toxicity of the liver and bone marrow, which require regular monitoring with blood testing. It can cause headache and drowsiness, which may resolve if the dose is lowered. Methotrexate can cause itching, skin rash, dizziness, and hair loss. A dry, non-productive cough can be a result of a rare lung toxicity.