Repost: Methotrexate

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Methotrexate

http://www.orthop.washington.edu/Bone%20and%20Joint%20Sources/xzzzzjzz1_1.html

Methotrexate (Rheumatrex) is a medicine that is used to treat rheumatoid

arthritis (RA) psoriatic arthritis, Reiter's syndrome, and other

conditions. First developed to treat certain types of cancer,

methotrexate is routinely used at higher doses as a cancer therapy and

is now used at much lower doses to treat rheumatic diseases, like

rheumatoid arthritis. Methotrexate has been studied for over 20 years in

the treatment of rheumatoid arthritis, and in 1988 was approved for this

use in adults by the U.S. Food and Drug Administration (FDA).

This medicine acts by altering the body's use of folic acid (a vitamin),

which is needed for cell growth. Scientists suspect that this

interference with folic acid is an important reason for methotrexate's

benefit in rheumatoid arthritis. Methotrexate belongs to a group of

medicines that are called " second-line therapies " or " disease-modifying

anti rheumatic drugs. " These drugs may affect the activity of RA to a

greater extent than commonly prescribed drugs, such as aspirin or other

nonsteroidal (non cortisone) anti-inflammatory drugs (NSAIDs).

Methotrexate is usually taken along with NSAIDs. It may begin to work as

early as three to six weeks after beginning treatment.

Methotrexate is used in both children and adults with active or

progressive rheumatoid arthritis, although FDA approval is only for

adults. It may be prescribed after trying one or more other second-line

therapies such as antimalarials or gold salts. It also may be

recommended even before starting these drugs. The decision to begin

methotrexate will be based upon the opinions of both you and your doctor

regarding the progression and activity of your disease. Methotrexate

benefits a high percentage of those who use the drug. This improvement

includes a decrease in the number of painful and swollen joints, as well

as an overall reduction in RA disease activity.

Methotrexate is taken once a week, either orally (as pills) or by

injection. The tablet strength is 2.5 milligrams, and the starting dose

is usually three pills (7.5 milligrams) taken one day a week. The dose

may be increased over time if there is no initial benefit. Generally,

doses between 7.5 and 20 milligrams one day a week are used to treat

rheumatoid arthritis. Doses higher than 20 milligrams weekly may

occasionally be used.

If taken orally, methotrexate may be taken all in one dose or split up

and taken two or three times over a 24-hour period, once a week. For

example, you can take it all on Monday morning or on Monday morning,

Monday evening, and finally on Tuesday morning. It may also be given

injection either just under the skin, in the muscle, or directly into

the vein. Injections may be recommended for people who are not

responding to oral methotrexate or are developing intestinal side

effects such as nausea.

Methotrexate should not be taken more often than one 24-hour period per

week. More frequent administration can be associated with serious side

effects. You should take the medicine on the same each week. Mark a

calendar to remind yourself when to take your dose. If you become

confused about when to take the drug, call your doctor to clarify the

situation before you take the next dose.

Side effects do occur in some people taking methotrexate. At the low

weekly doses used to treat rheumatoid arthritis however, serious side

effects are rare. The most common side effects include upset stomach,

nausea, vomiting, loss of appetite, diarrhea, or mouth sores. If these

develop, you should contact your doctor immediately. A change in the

dose or in how you take your methotrexate may reduce these side effects.

Occasionally, side effects such as headaches, dizziness, mood

alterations, skin rashes, or unexplained weight loss may occur.

Increased sensitivity to sun has also been observed, although this is

rare. Your blood count may decrease, but this uncommon with weekly low

doses of methotrexate. This could include a decrease in the number of

white blood cell that help fight infection. A decrease in the platelet

count or red blood cell count may also occur, which could lead to

bruising, bleeding, or fatigue. Factors that increase the possibility

for these blood cell changes with methotrexate include pre-existing

kidney disease, low levels of folic acid, certain infections, and the

use of certain medications, including an antibiotic called

trimethoprim/sulfamethoxazole (Bactrim or Septra).

If you should get the flu or another infection, you should call your

doctor promptly to find out if you should continue to take your

methotrexate while you are sick. Dehydration (loss of fluids) can

increase your risk of side effects.

Whenever a new medication is recommended, consult your doctor to make

sure there is no problem taking it with methotrexate. You should not

take the antibiotic trimethoprim/sulfamethoxazole (Bactrim or Septra)

with methotrexate. In some people, a shortage of folic acid can occur

with methotrexate therapy. Therefore, your doctor may prescribe

supplemental folic acid pills.

Rarely, lung damage occurs with this drug. Call your doctor immediately

if you develop a cough, progressive shortness of breath, and fever.

Methotrexate may also cause liver damage, although this is rare in

patients with RA. Since regular use of alcoholic beverages can increase

the risk of liver damage, you are advised to stop drinking alcohol while

on methotrexate. This issue should be discussed with your doctor.

Blood tests will be done on a regular basis to monitor your liver and

bone marrow for changes. After several years of methotrexate therapy,

your doctor may recommend a liver biopsy to examine directly the effects

of methotrexate on your liver. At this time, there are no standard

recommendations on the necessity or timing of doing a liver biopsy. If

you have concerns or questions, they should be discussed with your

doctor.

To reduce the potential for side effects from methotrexate, regular

laboratory tests are absolutely necessary. Prior to starting

methotrexate, standard blood tests should be performed. A chest x-ray is

strongly recommended. Once you start therapy, routine blood tests will

be performed. The time between tests will be shorter at the beginning of

therapy and may be longer when you are on maintenance therapy.

Please be certain to keep your scheduled laboratory monitoring and

doctor appointments since many side effects can be detected before they

become serious. Side effects are often a sign that your medication

should be changed or stopped. Sometimes a change in dosage of

methotrexate will eliminate or alleviate side effects.

Methotrexate may cause birth defects if taken by a woman at the time of

conception or during pregnancy. Women of childbearing potential must use

birth control and must not get pregnant while receiving methotrexate.

After methotrexate treatment is stopped, women should wait at least one

menstrual cycle before trying to conceive. Methotrexate has no effect on

fertility, and if the drug is stopped at least 30 days prior to

attempting conception, there will be no effect on the unborn child.

Breast-feeding is not recommended while taking methotrexate, because the

medicine may be passed to the child through the mother's milk.

Methotrexate may lower the sperm count in men. The sperm count should

normalize with drug discontinuation. There is little information

available regarding the risk of birth defects from a father taking

methotrexate at the time of conception. However, it is recommended that

males discontinue methotrexate three months prior to attempting

conception.

Frequently children with juvenile rheumatoid arthritis and related forms

of pediatric arthritis are also commonly treated with methotrexate,

usually by mouth, but occasionally by intramuscular or intravenous

injection. The side effects are similar in children and adults. Dosages

of methotrexate for children are calculated by body weight or body

surface area and are then adjusted as the child grows. Methotrexate

treatment for children with arthritis may help them more easily attend

school, achieve normal stature, and reach other age-appropriate

developmental milestones.

Even though methotrexate has not yet received approval from the U.S.

Food and Drug Administration for use in JRA, it is being used widely by

arthritis specialists to treat this disease. The decision to start

methotrexate or any second-line drug is a critical part of the treatment

of a child or adult with rheumatoid arthritis. It is important for a

specialist in arthritis to be a part of this decision. If you are under

the care of another type of doctor, it is appropriate to ask about a

consultation with an arthritis specialist before you begin treatment

with methotrexate. Since methotrexate is used for other conditions,

other doctors completely familiar with the effects of methotrexate may

dispense and monitor the drug, but periodic re-evaluation with a

arthritis specialist is recommended for people with RA and JRA.

As with other drugs used to treat adult and juvenile RA, there is no

guarantee that methotrexate will work for everyone. However, many

arthritis specialists agree that when methotrexate is properly used, the

risk of side effects is less than the risk to your health from the

disease itself. Talk to your doctor about your disease and the

treatments available to you. Communication between you and your doctor

is important.

Adapted from a pamphlet originally prepared for the Arthritis

Foundation. This material is protected by copyright.