If you have rheumatoid arthritis (RA) or severe psoriasis, there’s a good chance you’re taking methotrexate (MTX). This disease-modifying anti-rheumatic drug (DMARD) has a long history of effectively treating inflammatory autoimmune conditions, yet it also has the potential to raise your risk of developing certain infections.
Does being on methotrexate right now put you at high risk for contracting COVID-19?
“We don’t know how much methotrexate may contribute to being more susceptible to coronavirus,” says rheumatologist Joseph E. Huffstutter, MD, partner with Arthritis Associates in Hixson, Tennessee.
What we do know is that stopping this drug can have serious ramifications for the management of your condition: “If your disease flares you’ll have more trouble because you’ll need more medication to get a flare under control,” he explains.
Vinicius Domingues, MD, a rheumatologist in Daytona Beach, Florida, agrees that most patients should continue taking methotrexate — unless they develop symptoms of COVID-19 (more on that shortly).
Recently published clinical guidance from the American College of Rheumatology echoes this recommendation to continue methotrexate in the absence of COVID-19 symptoms.
Methotrexate was originally developed as a chemotherapy drug designed to kill fast-growing cancer cells, although it is important to note that arthritis and psoriasis patients take substantially lower doses than cancer patients. (Anywhere from 100 to 300 mg is a typical chemotherapy dose; patients with inflammatory conditions like RA are usually prescribed 10 to 25 mg.)
“Methotrexate keeps cells from dividing,” says Dr. Huffstutter. “When you have active rheumatoid arthritis, the fastest-growing cells are those in the immune system. That’s how it works to suppress the immune system in someone whose immune system is overactive. We’re trying to downregulate it and make it more normal.”
More specifically, methotrexate works by blocking some of the actions of the vitamin folic acid in the body. That’s an important part of how high doses of MTX work to thwart cancer, because folic acid is required to help cells divide and replicate.
Although the most commonly reported side effects of methotrexate are fatigue, nausea, stomach pain, and loss of appetite, methotrexate might also raise your risk of some infections.
Fortunately, most arthritis patients who use this drug do not develop more infections, though if you’re also taking other DMARDs or an additional biologic agent, the risk of infections is greater.
You can read more here about methotrexate side effects.
To make sure that methotrexate hasn’t impacted your body’s production of red blood cells, platelets, and white blood cells (which help fight infections), anyone taking this drug should have a complete blood count every three months. Here is more information about how doctors monitor for methotrexate side effects.
While this blood test should give you and your doctor some indication of whether your immune system has been substantially impacted by methotrexate, it might be more difficult to get routine blood work done during the COVID-19 crisis.
If you’re due for a check, call your doctor’s office and ask whether you should get your blood test as scheduled. Patients who have been stable on methotrexate for a long time may be advised to wait an extra month, says Dr. Huffstutter.