Brand name:
ONOTREX (Methotrexate)
Pronounced: meth-oh-TREX-ate
Brand names: Rheumatrex, Trexall
Why is ONOTREX (Methotrexate) prescribed?

ONOTREX (Methotrexate) is an anticancer drug used in the treatment of lymphoma (cancer of the lymph nodes) and certain forms of leukemia. It is also given to treat some forms of cancers of the uterus, breast, lung, head, neck, and ovary. ONOTREX (Methotrexate) is also given to treat rheumatoid arthritis when other treatments have proved ineffective, and is sometimes used to treat very severe and disabling psoriasis (a skin disease characterized by thickened patches of red, inflamed skin often covered by silver scales).
Most important fact about ONOTREX (Methotrexate)

Be certain to remember that in the treatment of psoriasis and rheumatoid arthritis, ONOTREX (Methotrexate) is taken once a week, not once a day. Accidentally taking the recommended weekly dosage on a daily basis can lead to fatal overdosage. Be sure to read the patient instructions that come with the package.
How should you take ONOTREX (Methotrexate)?

Take ONOTREX (Methotrexate) exactly as prescribed, and promptly report to your doctor any new symptoms that may develop.

ONOTREX (Methotrexate) is given at a higher dosage for cancer than for psoriasis or rheumatoid arthritis. After high-dose ONOTREX (Methotrexate) treatment, a drug called leucovorin may be given to limit the toxic effects.

If you miss a dose...

Skip it and go back to your regular schedule. Do not take 2 doses at once.

Storage instructions...

Store at room temperature, away from light.
ONOTREX (Methotrexate) side effects

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine whether it is safe for you to continue taking ONOTREX (Methotrexate).

* Side effects may include:
Abdominal pain and upset, chills and fever, decreased resistance to infection, dizziness, fatigue, general feeling of illness, mouth ulcers, nausea

If you are taking ONOTREX (Methotrexate) for psoriasis, you may also experience hair loss and/or sun sensitivity, and your patches of psoriasis may give a burning sensation.

ONOTREX (Methotrexate) can sometimes cause serious lung damage that makes it necessary to limit the treatment. If you experience a dry cough, fever, or breathing difficulties while taking ONOTREX (Methotrexate), be sure to tell your doctor right away.

During and immediately after treatment with ONOTREX (Methotrexate), fertility may be impaired. Men may have an abnormally low sperm count; women may have menstrual irregularities.

People on high doses of ONOTREX (Methotrexate) may develop a brain condition signaled by confusion, partial paralysis, seizures, or coma.
Why should ONOTREX (Methotrexate) not be prescribed?

Do not take ONOTREX (Methotrexate) if you are sensitive to it or it has given you an allergic reaction.

Do not take ONOTREX (Methotrexate) if you are pregnant.

ONOTREX (Methotrexate) treatment is not suitable for you if you suffer from psoriasis or rheumatoid arthritis and also have one of the following conditions:

Abnormal blood cell count
Alcoholic liver disease or other chronic liver disease
Alcoholism
Anemia
Immune-system deficiency
Special warnings about ONOTREX (Methotrexate)

Before you start taking ONOTREX (Methotrexate), your doctor will do a chest X-ray plus blood tests to determine your blood cell counts, liver enzyme levels, and the efficiency of your kidney function. While you are taking ONOTREX (Methotrexate), the blood tests will be repeated at regular intervals; if you develop a cough or chest pain, the chest X-ray will be repeated.

If you are being treated for psoriasis or rheumatoid arthritis, your doctor will test your liver function at regular intervals. You should avoid alcoholic beverages while taking ONOTREX (Methotrexate).

You may develop an opportunistic infection--one that takes advantage of your altered body chemistry--while you are taking ONOTREX (Methotrexate). Before receiving an immunization or vaccination, be sure to inform health care workers that you are taking ONOTREX (Methotrexate).

Older or physically debilitated people are particularly vulnerable to toxic effects from ONOTREX (Methotrexate). Your doctor will prescribe ONOTREX (Methotrexate) with great caution if you have any of the following:

Active infection
Liver disease
Peptic ulcer
Ulcerative colitis
Possible food and drug interactions when taking ONOTREX (Methotrexate)

If you are being given ONOTREX (Methotrexate) for the treatment of cancer or psoriasis, you should not take aspirin or other nonsteroidal painkillers such as Advil or Naprosyn; this combination could increase the toxic effects of ONOTREX (Methotrexate). If you are taking ONOTREX (Methotrexate) for rheumatoid arthritis, you may be able to continue taking aspirin or a nonsteroidal painkiller, but your doctor should monitor you carefully.

Other drugs that may increase the toxic effects of ONOTREX (Methotrexate) include:

Cisplatin (Platinol)
Penicillins
Phenylbutazone
Phenytoin (Dilantin)
Probenecid
Retinoid drugs such as Retin-A and Renova
Sulfa drugs such as Bactrim and Gantrisin

Sulfa drugs may increase ONOTREX (Methotrexate)'s toxic effect on the bone marrow, where new blood cells are made.

Certain antibiotics, including tetracycline (Sumycin) and chloramphenicol (Chloromycetin), may reduce the effectiveness of ONOTREX (Methotrexate). This is also true of vitamin preparations that contain folic acid.

In addition, ONOTREX (Methotrexate) can alter the effect of theophylline (Quibron, Theo-Dur).
Special information if you are pregnant or breastfeeding

A woman should not start ONOTREX (Methotrexate) therapy until the doctor is sure she is not pregnant. Because ONOTREX (Methotrexate) causes birth defects and miscarriages, it must not be taken during pregnancy by women with psoriasis or rheumatoid arthritis. It should be taken by women being treated for cancer only if the potential benefit outweighs the risk to the developing baby. In fact, a couple should avoid pregnancy if either the man or the woman is taking ONOTREX (Methotrexate). After the end of ONOTREX (Methotrexate) treatment, a man should wait at least 3 months, and a woman should wait for the completion of at least one menstrual cycle, before attempting to conceive a child.

ONOTREX (Methotrexate) should not be taken by a woman who is breastfeeding; it does pass into breast milk and may harm a nursing baby.
Recommended dosage for ONOTREX (Methotrexate)

Treatment with ONOTREX (Methotrexate) is highly individualized. Your doctor will carefully tailor your dosage of ONOTREX (Methotrexate) in order to avoid serious side effects and possible under- or overdosing.
Overdosage

Taken in excess, ONOTREX (Methotrexate) can cause serious and even fatal damage to the liver, kidneys, bone marrow, lungs, or other parts of the body. Symptoms of overdosage may include lung or breathing problems, mouth ulcers, or diarrhea. Initially, however, serious damage caused by ONOTREX (Methotrexate) may be apparent only in the results of blood tests. For this reason, careful, regular monitoring by your doctor is necessary. If for any reason you suspect symptoms of an overdose of ONOTREX (Methotrexate), seek medical attention immediately.