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More serious, but relatively uncommon side effects include:
- Increased risk for infections, particularly shingles and pneumonia. Methotrexate suppresses the immune system. Patients with active infections should avoid this drug.
- Infertility, miscarriage, and birth defects. This drug should not be used during pregnancy, because it can cause miscarriages or birth defects. It may harm fertility in men.
- Kidney damage.
- Liver damage, most commonly in patients with existing liver problems. Regular monitoring for liver toxicity includes blood tests and sometimes liver biopsies. Patients who are properly monitored rarely have any permanent liver damage.
- Cough and shortness of breath. Risk factors for these side effects include diabetes, existing lung problems, protein in the urine, and the use of rheumatoid arthritis drugs of a type called DMARD.
- Severe anemia. Folic acid supplements can offset this effect.
- Toxic effects on bone marrow. This can cause reduced blood cell production.
Despite methotrexate's side effects, some experts view it as the best therapy for widespread plaque psoriasis. It may also be effective for some patients with generalized erythrodermic and pustular psoriasis.
Methotrexate appears to be effective in children, but more safety research is needed.
Drug Interactions. Many drugs interact with methotrexate, occasionally with harmful results. For example, the antibiotic trimethoprim-sulfamethoxazole increases the toxicity of methotrexate.
Taking nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen, or naproxen at the same time as methotrexate may change the blood levels of methotrexate. Always talk with your doctor before taking these or any other medications in combinations.
People Who Should Avoid Methotrexate. Pregnant and nursing mothers should never take methotrexate because it increases the risk for severe, even fatal, birth defects and miscarriage. The drug should be discontinued several months before the actual pregnancy. Methotrexate may also cause temporary impairment of fertility in men.
People with the following conditions are unlikely to be given methotrexate:
- Alcoholism
- Anemia or other blood abnormalities
- Kidney problems
- Liver problems (including hepatitis)
- Peptic ulcers
- Suppressed immune system
Oral Retinoids
Oral retinoids are vitamin A-related medications taken by mouth. This group of medicines is also a first-line treatment for adults with severe psoriasis. Oral retinoids used for psoriasis include acitretin (Soriatane) and isotretinoin (Accutane).
Acitretin is the retinoid of choice and may be dramatically effective for severe psoriasis, particularly pustular or erythrodermic types. It is also effective in a low-dose formulation for symptoms of nail psoriasis. When used alone, it is much less effective against more common forms of psoriasis, such as plaque or guttate psoriasis. However, when combined with PUVA phototherapy it can markedly improve the response, even in patients with these forms of psoriasis.
Accutane, more commonly used to treat acne, is far less potent than acitretin, but it may still be effective against pustular psoriasis. The drug may also be effective with phototherapy.
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Review Date: 10/21/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine,
Harvard Medical School. Also reviewed by David Zieve, MD, MHA,
Medical Director, A.D.A.M., Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
