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Common uses
Methotrexate is used to treat several different types of rheumatic disease, including rheumatoid arthritis and psoriatic arthritis. Methotrexate can reduce inflammation and also can affect the immune system (the body's own defence system). One of its actions is to reduce the activity of the immune system, so it is always used with care.
Before using
Do not use this medication if you are allergic to methotrexate. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you have:
• liver disease;
• alcoholism or cirrhosis of the liver;
• a blood cell disorder such as anemia (lack of red blood cells) or leukopenia (lack of white blood cells);
• a bone marrow disorder; or
• if you are breast-feeding a baby.
Methotrexate is sometimes used to treat cancer even when patients do have one of the conditions listed above. Your doctor will decide if this treatment is right for you.
Before using methotrexate, tell your doctor if you are allergic to any drugs, or if you have:
• kidney disease;
• liver disease;
• lung disease or pneumonia;
• stomach ulcers;
• any type of infection; or
• if you are receiving radiation treatments.
Directions
Methotrexate is usually taken in tablet form ONCE A WEEK on the same day. It should be taken with food. The tablets should be swallowed whole and not crushed or chewed.
Methotrexate may also be given once a week by injection – subcutaneous (an injection under the skin, like insulin injections for diabetes), or intramuscular (into the buttock or thigh). Methotrexate has recently also been licensed for intravenous use (injection into the vein).
Cautions
Methotrexate has rarely caused serious side effects. Therefore, this medication should be used only to treat cancer or severe cases of psoriasis or rheumatoid arthritis. Women must avoid becoming pregnant while taking this medication. Pregnant women who have psoriasis or rheumatoid arthritis must not use methotrexate.
Possible side effects
The most common side effects of methotrexate include nausea or vomiting and abnormalities in liver function tests. These side effects are more likely to occur at higher doses. About 1 to 3 percent of patients develop mouth sores (called stomatitis), rash, diarrhea and abnormalities in blood counts. Methotrexate has been associated with cirrhosis (scarring) of the liver, but this side effect is rare and more likely to occur in patients who have underlying liver problems or are taking other drugs toxic to the liver.
Lung problems (persistent cough or unexplained shortness of breath) can occur when taking methotrexate. These side effects are more common in people with poor lung function. Persistent cough or shortness of breath should be reported to your doctor.
Slow hair loss is seen in some patients, but hair grows back when the medication is stopped. Methotrexate can increase the sensitivity of the skin to sunlight, so limiting sun exposure and the use of sunscreen is advised.
The use of folate supplements (folic and folinic acid), which are B vitamins, can decrease side effects during methotrexate treatment.
It is important to remember that most patients do not experience any side effects and many of the minor side effects will improve with time. Methotrexate treatment should be discontinued before attempting to become pregnant. Even though methotrexate cannot be taken during pregnancy, it does not reduce a woman’s chance of becoming pregnant in the future.
If you take too much
Seek emergency medical attention if you think you have used too much of this medicine. An overdose of methotrexate can be fatal.
Overdose symptoms may include pale skin, easy bruising or bleeding, unusual weakness, mouth sores, nausea, vomiting, black or bloody stools, coughing up blood or vomit that looks like coffee grounds, and urinating less than usual or not at all.
Additional information
Methotrexate can cause serious or life-threatening side effects on your liver, lungs, kidneys, and bone marrow (immune system). Do not take this medication in larger amounts, or take it for longer than prescribed. Follow the directions on your prescription label. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you have liver disease (especially if caused by alcoholism), a blood cell or bone marrow disorder, or if you are breast-feeding a baby. This medication can cause birth defects in an unborn baby. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you are pregnant. Use an effective form of birth control, whether you are a man or a woman. Tell your doctor if you or your sexual partner become pregnant during treatment.
To be sure this medication is not causing harmful effects, your blood will need to be tested on a regular basis. Your kidney or liver function may also need to be tested. Do not miss any scheduled appointments.
Drug interactions
Before taking methotrexate, tell your doctor if you are using any of the following drugs:
• azathioprine (Imuran);
• chloramphenicol (Chloromycetin);
• hydroxychloroquine (Plaquenil, Quineprox);
• retinol, tretinoin (Retin-A), isotretinoin (Accutane);
• steroids (prednisone and others);
• sulfa drugs such as Azulfidine, Bactrim, or Septra;
• phenytoin (Dilantin);
• probenecid (Benemid);
• tetracycline (Brodspec, Panmycin, Sumycin, Tetracap);
• theophylline (Elixophyllin, Slo-Bid, Theobid, Theo-Dur);
• gold treatments such as auranofin (Ridura) or aurothioglucose (Solganol);
• oral diabetes medications such as acetohexamide (Dymelor), chlorpropamide (Diabinese), glipizide (Glucotrol), glimepiride (Amaryl), or tolbutamide (Orinase);
• penicillin antibiotic such as ampicillin (Principen), amoxicillin (Amoxil, Trimox), carbenicillin (Geocillin), cloxacillin (Cloxapen), dicloxacillin (Dynapen), nafcillin (Unipen), oxacillin (Bactocill), penicillamine (Cuprimine, Depen), or Bee-Pen, Pen-Vee K, Veetids;
• salicylates such as aspirin, Disalcid, Doan's Pills, Dolobid, Salflex, Tricosal, and others; or
• NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen (Motrin, Advil), naproxen (Aleve, Naprosyn), diclofenac (Voltaren), diflunisal (Dolobid), etodolac (Lodine), flurbiprofen (Ansaid), indomethacin (Indocin), ketoprofen (Orudis), ketorolac (Toradol), mefenamic acid (Ponstel), meloxicam (Mobic), nabumetone (Relafen), piroxicam (Feldene), and others.
This list is not complete and there may be other drugs that can interact with methotrexate. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
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Methotrexate
