Methotrexate for Psoriasis

Medically Reviewed by Stephanie S. Gardner, MD on March 18, 2022
4 min read

Methotrexate is a strong drug that could help clear up your psoriasis. It’s part of a class of medications called antimetabolites that stop cells from dividing and slow their growth.

In psoriasis, methotrexate blocks enzymes and cells that cause inflammation and puts the brakes on your too-active immune system. This can heal the scales on your skin and stop them from coming back.

Your doctor may prescribe methotrexate if your psoriasis covers more than 10% of your body or if topical medicines or light therapy don’t clear your skin. They may also suggest it if you have psoriasis in sensitive areas like your face, scalp, genitals, palms, feet, or the inside of your mouth.

Although no drug works for everyone, methotrexate improves psoriasis symptoms in many people. If it works for you, your skin will probably start to get better in 4 to 6 weeks. Some people have clear or nearly clear skin in 6 months.

Methotrexate costs less than some medications used for psoriasis. That means health insurance plans may pay for it more often than newer, more expensive drugs. These are reasons your doctor may prescribe it instead of biologics, which work better for psoriasis.

If methotrexate doesn’t clear or nearly clear your skin, ask your doctor to suggest one of the many other drugs that work well for psoriasis.

Your doctor can prescribe methotrexate as a pill, liquid, or injection you can give yourself at home. Most of the time, your doctor will prescribe the pill form. If the pills upset your stomach, they may suggest injections, which usually don’t cause nausea.

Most people with psoriasis take methotrexate once a week. Your doctor will choose a dose based on what’s best for your body and the severity of your psoriasis.

If you’re prescribed methotrexate in pill form, swallow it whole – don’t crush, break, or chew it. You could have serious health issues if you take methotrexate the wrong way or take it more often than prescribed. Tell your doctor if it’s hard for you to swallow pills.

Take the time to read all instructions for your methotrexate, and follow them carefully. If you have questions about how or when to take it, check with your doctor or pharmacist before you start.

It’s important that you take methotrexate on the same day every week. If you miss a dose, call your doctor. Do not take a double dose: It could cause serious health issues.

The most common side effects are:

  • Vomiting
  • Nausea
  • Loss of appetite
  • Mouth sores or redness and swelling in the mouth
  • Fatigue
  • Tiredness, headache, or brain fog
  • Sun sensitivity

You may have more serious side effects, including less ability to fight off infections or liver, lung, or kidney issues. Your doctor will probably do a blood test every few months to make sure methotrexate is not damaging these organs.

Talk to your doctor or dermatologist right away about any side effect you notice. Most can be controlled with a tweak to your treatment plan. A folic acid supplement may also help.

If side effects still bother you, ask your doctor to prescribe another treatment. There are now many treatments that work well for psoriasis. This means you don’t have to live with medications that make you feel bad.

Your doctor should try different treatments until they find one that clears your psoriasis with few or no side effects.

Don’t take methotrexate if you:

  • Have unhealthy alcohol use or any kind of liver disease
  • Have an active peptic ulcer
  • Have a low white blood cell count, low platelets, or anemia
  • Have liver or kidney problems
  • Are pregnant, nursing, or trying to conceive (this goes for all genders)
  • Have an infection or HIV or another immunodeficiency syndrome

Your doctor may have you take one or more drugs with methotrexate, but check with them before you take any medication besides those they’ve prescribed. This includes over-the-counter medications, supplements, or herbal remedies.

If you see a health care provider besides the doctor who prescribes your methotrexate, be sure you tell them that you take this drug. That’s because methotrexate doesn’t mix well with several types of drugs, including:

  • Aspirin
  • Ibuprofen and other NSAIDs (nonsteroidal anti-inflammatory drugs)
  • Some antibiotics
  • Some asthma medications
  • Some epilepsy medications
  • Some indigestion medications
  • Some diuretics

You may stop taking methotrexate once your psoriasis is under control, and begin again if you have a flare. Or you may take it for years. Check with your doctor. How long you take it may depend on whether it clears your skin and how well your body tolerates it.

Once called amethopterin, methotrexate was originally used to treat cancer. The dose you take for psoriasis is much lower than those used for people with cancer, however. Doctors also use low-dose methotrexate to treat other diseases that affect the immune system, such as rheumatoid arthritis, Crohn’s disease, and multiple sclerosis.