What You Should Know About Methotrexate for Psoriatic Arthritis

You may have heard of psoriasis or arthritis. But there’s another autoimmune condition known as psoriatic arthritis. This is an autoimmune condition that involves both psoriasis and inflammatory arthritis. It can cause joint pain, inflammation, and skin problems. It’s more common for people with psoriasis or people who have family members with psoriasis.

Untreated psoriatic arthritis can lead to joint damage over time, so it's important to see a rheumatologist if you have psoriatic arthritis. In some cases, immunosuppressant medications may be needed. One immunosuppressant, methotrexate (Trexall), is a common medication option for active psoriatic arthritis. Here, we’ll cover everything you need to know about methotrexate for psoriatic arthritis.

What is methotrexate?

Methotrexate is part of a medication class known as disease-modifying antirheumatic drugs (DMARDs). DMARDs are used to treat many conditions like rheumatoid arthritis, lupus, and more.

Promotional Disclosureinfo_outlined

SPECIAL OFFER

Save over 40% on Qsymia with GoodRx

Discover the once daily Qsymia for weight management. Qsymia is for adults and children 12-17 in combination with a healthy diet and regular exercise.

Save now

Methotrexate is FDA approved to treat some cancers when used at high doses (chemotherapy). When used at low doses, methotrexate can treat a variety of autoimmune conditions, such as rheumatoid arthritis, polyarticular juvenile idiopathic arthritis, and psoriasis. At these low doses, methotrexate is not considered chemotherapy.

Methotrexate isn’t FDA-approved to treat psoriatic arthritis specifically, but it’s used off-label for this reason. 

How effective is methotrexate at treating psoriatic arthritis?

In recent years, the effectiveness of methotrexate for psoriatic arthritis has come into question. For people with severe arthritis or severe psoriasis, starting with a biologic medication, like Humira (adalimumab), is likely a better choice for best results. It’s also reasonable to start a biologic if you have milder symptoms.  

Promotion disclosure

Methotrexate

Avg retail price

$31.53(Save 60.80%)

GoodRx discount

$12.36

Compare all prices

But methotrexate may still be a good first-choice option for many people. This includes people who:

• Can’t afford biologic medications. Methotrexate is much less expensive than biologic medications.

• Have milder symptoms.

• Prefer pills. Most biologics are injections.

• Are at high risk of infection. Or those who have had serious infections in the past.

• Have a history of cancer. Or those who are currently receiving treatment for cancer.

How does methotrexate for psoriatic arthritis work?

DMARDs like methotrexate are immunosuppressants. The immune system is normally responsible for fighting infections. But in autoimmune diseases like psoriatic arthritis, the immune system starts to attack healthy cells in the body. 

Medications like methotrexate work to stop the body from attacking healthy cells, by interrupting processes in the body that cause inflammation. 

There are various ways that methotrexate lowers inflammation. This includes both increasing levels of adenosine, a chemical with anti-inflammatory properties, and causing T-cell death, which lowers the body’s overactive immune system.

Methotrexate improves the symptoms of psoriatic arthritis, including psoriasis rashes, joint swelling, and joint pain. Methotrexate can also prevent psoriatic arthritis from getting worse, lowering the chance of long-term joint damage.

How do you take methotrexate for psoriatic arthritis?

Methotrexate is usually taken as a single dose once per week. It comes as an injection or oral tablet. People with psoriatic arthritis usually take methotrexate orally. 

“The usual dose is somewhere between 7.5mg to 25mg per week,” says Dr. Samantha Shapiro, a board-certified rheumatologist and internist. “However, most rheumatologists will attest that 15mg is typically the minimum effective dose.” 

The pills only come in a 2.5 mg dose. So you have to take several at once to reach a dose that’s effective. Your healthcare provider may start you at a lower dose and increase it if you need more symptom relief. The dose can also be lowered if you experience bothersome side effects.

You’ll also receive a prescription for high dose folic acid along with your methotrexate prescription. Folic acid is a vitamin that helps prevent some of the common methotrexate side effects. It should be taken once a day and can be purchased over-the-counter (OTC) or with a prescription. The prescription strength tablets are 1000 mcg (1mg). But most OTC products contain less folic acid, usually 400 mcg to 800 mcg per tablet. Talk to your healthcare provider about what dose of folic acid is best if you’re taking methotrexate.

What are the side effects of methotrexate?

Methotrexate is known to have some common side effects. But it can cause more serious side effects, too.

Common side effects

Some common side effects of methotrexate include:

• Abnormal liver labs

• Nausea and vomiting

• Sores in the mouth

• Low platelets

• Dizziness

• Increased skin sensitivity with sun exposure (photosensitivity)

• Hair loss

• Diarrhea

• Fatigue or flu-like symptoms, especially the day after taking the medication

Of note, gastrointestinal symptoms (nausea, vomiting, diarrhea) and fatigue often go away as your body gets used to the medication. 

Serious side effects

It’s important to see your healthcare provider regularly while taking methotrexate. It’s also important to complete any labs or monitoring they recommend. This may help avoid serious side effects, including:

• Severely low blood cell counts that can raise the risk of infection or bleeding

• Severe liver damage

• Kidney problems

• Lung inflammation 

• Serious skin conditions, including Stevens-Johnson syndrome

Some of these side effects are more common with the higher doses of methotrexate used for chemotherapy, and less likely with the doses used for psoriatic arthritis. For more information on how to recognize potentially serious side effects and when to contact your healthcare provider (or seek emergency care), check out our in-depth article on methotrexate toxicity.

What are some alternatives to methotrexate for psoriatic arthritis?

The treatment plan for psoriatic arthritis will depend on what symptoms you have and how severe they are. Other health conditions and any previous history of treatment are important considerations too.

Medications that treat psoriatic arthritis are immunosuppressants. Besides DMARDs like methotrexate, other medications can also treat psoriatic arthritis. These include biologics and small molecule drugs. Examples include:

• Tumor necrosis factor alpha (TNF-alpha) inhibitors. Examples include Enbrel (etanercept) and Humira (adalimumab). 

• Interleukin inhibitors like Cosentyx (secukinumab) and Stelara (ustekinumab)

• T-cell inhibitors like Orencia (abatacept)

• Janus kinase inhibitors like Xeljanz (tofacitinib) and Rinvoq (upadacitinib)

• Phosphodiesterase-4 (PDE4) inhibitors like Otezla (apremilast)

Who shouldn’t use methotrexate for psoriatic arthritis?

If you are pregnant, or considering becoming pregnant, you shouldn’t use methotrexate. It could cause harm to an unborn baby. Talk to your healthcare provider about other medication options for psoriatic arthritis if you’re pregnant or trying to become pregnant.

But if you're the partner of someone who's pregnant or trying to become pregnant, experts generally recommend that you continue methotrexate since the risk of harm to the baby is very low. 

Methotrexate should also be avoided if you have:

• An allergy to methotrexate

• Alcohol use disorder

• Chronic liver disease, including damage that’s due to heavy alcohol use (alcoholic hepatitis) or scarring of the liver (cirrhosis)

• Kidney disease

It’s best to avoid drinking alcohol while taking methotrexate. Alcohol increases the chances of liver damage with methotrexate.

Why trust our experts?

Written by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Samantha C. Shapiro, MD

Samantha Shapiro, MD, is a board-certified rheumatologist and internist with expertise in autoimmune and inflammatory conditions. She founded the division of rheumatology at Dell Medical School at The University of Texas at Austin.

Our editorial standards

Meet our experts