In Treatment of:
Methotrexate has been used for decades to treat psoriasis and some cancers. It is used to treat rheumatoid arthritis and other forms of inflammatory arthritis and also may be used to treat lupus, inflammatory myositis, vasculitis and some forms of childhood arthritis.
Methotrexate is one of the most effective and commonly used medicines in the treatment of several forms of arthritis and other rheumatic conditions. It is known as a disease-modifying anti-rheumatic drug (DMARD), because it not only decreases the pain and swelling of arthritis, but it also can decrease damage to joints and long-term disability.
The most common side effects of methotrexate include nausea or vomiting and abnormalities in liver function tests. Liver function tests are blood tests your doctor may order to watch your liver. These side effects are more likely to occur at higher doses. About 1-3% of patients develop mouth sores (called stomatitis), rash, diarrhea, and abnormalities in blood counts. Methotrexate may cause cirrhosis (scarring) of the liver, but this side effect is rare and most likely to occur in patients who already have liver problems or are taking other drugs that are 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 person stops taking this medication. 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) often are given with methotrexate. These are B vitamins and can decrease side effects during methotrexate treatment.
It is important to remember that most patients do not experience side effects, and that, for those who do, many of the minor side effects will improve with time. Methotrexate treatment should be discontinued for at least three months before attempting to become pregnant. Even though methotrexate should not be taken during pregnancy, it does not reduce a woman’s chance of becoming pregnant in the future. Men taking methotrexate should talk to their physician prior to attempts to conceive.
Methotrexate can cause fetal death or teratogenic effects when administered to a pregnant woman. Methotrexate is contraindicated in pregnant women with psoriasis or rheumatoid arthritis and should be used in the treatment of neoplastic diseases only when the potential benefit outweighs the risk to the fetus. Women of childbearing potential should not be started on methotrexate until pregnancy is excluded and should be fully counseled on the serious risk to the fetus (see PRECAUTIONS) should they become pregnant while undergoing treatment. Pregnancy should be avoided if either partner is receiving methotrexate; during and for a minimum of three months after therapy for male patients, and during and for at least one ovulatory cycle after therapy for female patients.
Because of the potential for serious adverse reactions from methotrexate in breast fed infants, it is contraindicated in nursing mothers.
Patients with psoriasis or rheumatoid arthritis with alcoholism, alcoholic Iiver disease or other chronic liver disease should not receive methotrexate.
Patients with psoriasis or rheumatoid arthritis who have overt or laboratory evidence of immunodeficiency syndromes should not receive methotrexate.
Patients with psoriasis or rheumatoid arthritis who have preexisting blood dyscrasias, such as bone marrow hypoplasia, leukopenia, thrombocytopenia or significant anemia, should not receive methotrexate.
Patients with a known hypersensitivity to methotrexate should not receive the drug.
Do not use this medication if you are allergic to methotrexate. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you have:
1. liver disease;
2. alcoholism or cirrhosis of the liver;
3. a blood cell disorder such as anemia (lack of red blood cells) or leukopenia (lack of white blood cells);
4. a bone marrow disorder; or
5. 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.
If you have any of these other conditions, you may need a dose adjustment or special tests to safely take methotrexate:
1. kidney disease;
2. liver disease;
3. lung disease or pneumonia;
4. stomach ulcers;
5. any type of infection; or
6. if you are receiving radiation treatments.
FDA pregnancy category X. Methotrexate can cause birth defects in an unborn baby. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you are pregnant. Tell your doctor right away if you become pregnant during treatment.
Use birth control to prevent pregnancy while you are using methotrexate, whether you are a man or a woman. Methotrexate use by either parent may cause birth defects.
Before you start taking methotrexate, your doctor may want you to have a pregnancy test to make sure you are not pregnant.
If you are a man, use a condom to keep from causing a pregnancy while you are using methotrexate. Continue using condoms for at least 90 days after your treatment ends. If you are a woman, use an effective form of birth control while you are taking methotrexate, and for at least one cycle of ovulation after your treatment ends. Do not give this medicine to a child without the advice of a doctor.
Older adults may be more likely to have side effects from methotrexate.
Be sure to tell your doctor about all of the medications you are taking, including over-the-counter drugs and natural remedies, as some of these could increase the risk of methotrexate toxicity. Trimethoprim (Bactrim or Septra), an antibiotic often used for respiratory and urinary infections, may increase the toxicity of methotrexate. The level of methotrexate can be affected by nonsteroidal anti-inflammatory drugs (NSAIDs), although these often are prescribed together for the management of rheumatoid arthritis. Other drugs that can affect the liver may increase the risk of liver damage from methotrexate. Radiation therapy, used to treat some cancers, may increase the risk of serious side effects from methotrexate as well.
Methotrexate typically comes in 2.5 milligram (mg) tablets. Adults with rheumatoid arthritis usually begin with a starting dose of 7.5 to 10 mg, or 3-4 pills, taken all together once a week. The dose may be increased to 20 to 25 mg a week over time if needed. The medication also can be given as a liquid or as an injection. This comes as 25 mg per 1 milliliter (mL) and is injected under the skin, like insulin, to reduce side effects or when higher doses are needed. Adults with other rheumatic conditions may take similar doses. In children with juvenile arthritis, the dose is based on the patient's weight.