Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
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. (Metabolism
consists of the production and destruction of important components of the cell
as well as the production of energy for use by the cell.) 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 immunity, which may play a role in causing rheumatoid arthritis.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS: Injectable: 25mg/ml; powder for injection 1 g. Tablet: 2.5, 5,
7.5, 10, and 15 mg
STORAGE: Store at room temperature 15° to 30°C (59° to 86°F), 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 and other rheumatic diseases, including polymyositis and
systemic lupus erythematosus. Methotrexate has been used to induce miscarriage
in patients with ectopic pregnancies.
DOSING: Methotrexate may be taken with or without food.
For rheumatoid
arthritis and psoriasis, the dose of methotrexate is given WEEKLY, by injection
or orally.
For psoriasis, the starting oral dose is a single 7.5 mg dose weekly
or 2.5 mg every 12 hours for three doses, once weekly.
DRUG INTERACTIONS: Using
nonsteroidal anti-inflammatory drugs (NSAIDs) before
or during methotrexate treatment may result in serious adverse events because
NSAIDS may increase the blood concentrations of methotrexate. Combining
methotrexate with drugs that adversely affect the liver or kidneys may result in
additional liver or kidney toxicity.
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.
NURSING MOTHERS: Methotrexate is excreted in
breast milk and should not be
used by nursing mothers.
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, kidneys and bone marrow, which require
regular monitoring with blood tests. 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 rare
lung toxicity.
Reference: FDA Prescribing Information
Last Editorial Review: 1/8/2008
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Rheumatoid Arthritis - Learn more about rheumatoid arthritis, an autoimmune disease that causes chronic joint inflammation, which has symptoms that include stiffness, fever, muscle and joint aches, loss of appetite, and fatigue. Treatment of rheumatoid arthritis incorporates the use of first-line drugs (aspirin and corticosteroids for pain and inflammation) and second-line drugs (methotrexate and hydroxychloroquine to prevent joint destruction and promote remission).
- Drugs: What You Should Know About Your Drugs - Find out what you should know about your drugs such as side effects, warnings and precautions, storage information, and if a generic version is as good as the brand name.
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