Methotrexate is a medication that has been used to treat psoriasis and psoriatic arthritis since 1972. Given in either oral form or by injection, it is used to suppress the immune system and slow cell turnover, both of which are involved in the development of psoriasis.
Many members of MyPsoriasisTeam have been treated with methotrexate. One member stated they were on “methotrexate for years” until it wasn’t as effective. While on methotrexate, “the psoriasis calmed down, and my body didn’t hurt.”
To better understand the use of methotrexate in psoriasis treatment, MyPsoriasisTeam spoke with Dr. Alexa Kimball. Dr. Kimball is a professor of dermatology at Harvard University, and is also CEO and president of Harvard Medical Faculty Physicians, Beth Israel Medical Center.
A medication in the class of antimetabolites, methotrexate works by blocking a cell’s ability to continue to replicate and make copies of itself. In psoriasis, an overactive immune system allows skin cells to have an abnormally fast growth cycle, which results in the symptoms of painful scales and plaques on the skin. Methotrexate suppresses inflammation and decreases the overproduction of skin cells.
Methotrexate is also used to treat rheumatoid arthritis and some cancers, although in those cases, it is typically given in much higher doses than it would be when treating psoriasis.
Methotrexate can be given orally in pill or liquid form, by subcutaneous injection under the skin, or through intravenous infusion. For psoriasis treatment, methotrexate is most often prescribed by dermatologists in pill form or as an injection, usually given once a week. When taking methotrexate, folic acid levels in the body may be depleted, and often, a folic acid supplement is recommended.
Initial therapy for psoriasis often involves a topical cream or ointment, such as a steroid cream. When topical therapy is no longer effective or does not provide adequate improvement in symptoms, systemic therapy is used. Methotrexate is a systemic therapy that can be used for moderate to severe psoriasis. This medication has not been used as frequently since biologics became available, as clinical trials have shown methotrexate to have a better treatment response over placebo, but reduced effectiveness when compared to biologic therapy.
“I definitely do use methotrexate,” Dr. Kimball said. “[But] I certainly use it less for psoriasis than I used to.” Methotrexate has a success rate of 25 percent to 30 percent as compared to biologics, which feature a success rate of 80 percent to 85 percent, she explained.
Dr. Kimball finds that the group in which she uses methotrexate most often includes people on the borderline of having too much disease for topical treatments, but not so much disease as to require biologics. “We also sometimes use it in combination with biologics because of its effectiveness,” she noted.
One of the benefits of using methotrexate to treat psoriasis is that methotrexate is inexpensive, especially compared to biologic therapy. In a 2010 study, estimated costs for a year of methotrexate therapy were around $1,200 as compared to a year of therapy with alefacept, a biologic medication no longer in use, which cost over $27,000. Dr. Kimball stated that in her experience, “sometimes insurers will ask you to try [methotrexate] first” before authorizing use of an expensive biologic medication.
Some MyPsoriasisTeam members have had to try methotrexate before their insurance companies would consider authorizing a biologic. One member commented, “I am just checking a box for the insurance company” while hoping for relief of symptoms.
Convenient dosing is also a benefit, as methotrexate generally only needs to be taken once weekly, and typically in pill form instead of injection or intravenous infusion. Dosing in pill form allows for the medication to be taken at home without any discomfort, and does not require you to travel to an infusion center. If needed to be given by injection, this is typically done by self-injection at home.
After just a few weeks of therapy, many people taking methotrexate noted an improvement in psoriasis symptoms, with maximum improvement typically observed after about three months of therapy. One MyPsoriasisTeam member started to notice an improvement in symptoms “three weeks after starting” and is “hoping for more.”
One drawback to using methotrexate is that it is not as effective in treating psoriasis as biologic therapyis, Dr. Kimball explained.
Methotrexate, when used over time, may cause accumulating toxicity, particularly liver disease. Although uncommon, taking methotrexate can increase the risk of developing some cancers, such as lymphoma, melanoma, and lung cancer.
Another drawback is that taking methotrexate typically also requires supplementation with folic acid. Often, people with psoriasis may take other medications as well, and sometimes the addition of more pills can be burdensome.
There is also a group of people in which methotrexate should not be used. This group includes:
Low-dose methotrexate given for psoriasis has the potential for side effects, but is generally well-tolerated. The most common side effects include:
Some side effects, such as kidney and liver dysfunction, have been found with long-term use of methotrexate. These risks can be higher in those with other underlying medical conditions, such as obesity or diabetes, or if taking other medications that affect kidney and liver function. Frequent alcohol use while taking methotrexate can also make liver damage more likely. Routine blood tests of kidney and liver function are typically performed to assess for these potential side effects.
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