Doctors may prescribe certain chemotherapy medications, such as methotrexate, in a different dose to treat rheumatoid arthritis (RA).

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Chemotherapy refers to medications that work by killing or interfering with cell function. Traditionally, oncologists have used them for treating cancer. These drugs can also kill normal cells.

However, since cancer cells usually are dividing more rapidly than normal cells, the medications target cancer cells first.

In some cases, doctors can use some of these medications to treat autoimmune conditions such as rheumatoid arthritis (RA). The drugs will target the immune cells, which, like cancer cells, are rapidly dividing. In this kind of treatment, the medications are called disease-modifying anti-rheumatic drugs (DMARDs).

Rheumatologists use DMARDs to treat RA because these drugs block the actions of the immune cells that are attacking healthy joints, which helps to prevent damage and slow down the progression of the disease.

In this article, we discuss these medications for the treatment of RA and how they work. We also cover the side effects and risks of this treatment.

Many people understand the function of chemotherapy drugs when they are used to treat cancer. Doctors prescribe these drugs to kill cancer cells or to prevent them from growing and spreading to other parts of the body.

Many of the DMARDs used for autoimmune disease can be used in cancer treatment along with many other classes of medications but in more intense protocols. These drugs are a common treatment option for autoimmune conditions, such as RA.

Doctors prescribe these drugs to treat RA at much lower dosages than they would for those with cancer. This is because the goal of treatment is not to kill cancer cells but to change the behavior of the overactive immune cells. The lower dosage also helps to reduce the severity of potential side effects.

An example of a common DMARD medication used to treat RA is methotrexate. Early treatment with DMARDs and other medications for RA can help slow the progression of the disease and reduce or prevent joint damage and other serious complications.

DMARDs that doctors may recommend for treating people with RA include:


Methotrexate (Otrexup, Rasuvo, Rheumatrex, Trexall) is one of the first-line treatment options for people with RA. Doctors consider it to be an effective treatment with typically minimal side effects.

People usually take methotrexate once weekly, either by mouth or injection. Doctors will also recommend taking a folic acid supplement to help reduce the effects on normal cells leading to clinical side effects.

According to the American College of Rheumatology, people usually first see an improvement in RA symptoms within 3–6 weeks of starting treatment. However, they may not begin to see the full benefit of methotrexate until after 12 weeks.


Cyclophosphamide (Cytoxan) is a potent drug that can cause more severe side effects than methotrexate.

Doctors typically only use this medication to treat severe complications of RA, specifically vasculitis, which is inflammation in the blood vessels.

They may also use it to treat complications of lupus, myositis, or scleroderma.


Azathioprine (Azasan, Imuran) works by suppressing the immune system, which may help some people with RA.

However, it can have side effects, so doctors will usually prescribe azathioprine for severe RA or in cases of serious organ complications. It is not particularly effective for joint inflammation.

Other options

Additional DMARDs approved by the Food and Drug Administration for RA treatment include:

RA involves inflammation that damages people’s joints over time, which can lead to pain, stiffness, and reduced mobility. This inflammation occurs due to an overactive immune system that is attacking the body’s tissues, especially tissue lining the joints.

In people with RA, the immune system mistakes healthy tissue in the joints for foreign invaders. It sends cells to attack the joints, which causes them to become inflamed and painful.

DMARDs help treat RA by blocking or interfering with the actions of these immune cells, which helps to prevent joint damage and slow down the progression of the disease.

In cancer treatment, the higher dosage and intense protocols of these medications have a stronger impact on the body and can cause more severe side effects. Although doctors usually prescribe DMARDs at lower dosages for RA, the treatment can still cause side effects.

People should report any side effects to their doctor, who may recommend adjusting the dosage or switching to another drug with more manageable side effects. They may also prescribe other medications to help treat or prevent side effects.

DMARDs can affect blood cell production in the body, which may lead to lower counts of red blood cells, white blood cells, or platelets.

Side effects of methotrexate can include:

However, research shows taking a folic acid supplement along with methotrexate will reduce the severity or prevent some of these side effects. Doctors will recommend regular blood tests to check for signs of problems while taking methotrexate.

People should see their doctor right away for more serious side effects, which can include:

  • dizziness
  • blurred vision
  • diarrhea
  • bloody stool
  • bloody vomit
  • shortness of breath
  • swelling in the legs

Doctors commonly use methotrexate and other DMARDs to treat autoimmune conditions such as RA. These drugs can help relieve symptoms and prevent further damage to joints.

In the treatment of RA, doctors prescribe these drugs at much lower doses than when used to treat cancer. They do not refer to the use of DMARDs in RA treatment as chemotherapy, as they are not targeting cancer.

A person with RA may still experience some side effects from treatment with DMARDs, though most people tolerate drugs such as methotrexate well. A person may not begin to notice any improvement until several weeks or longer after commencing treatment.

People should discuss any side effects with their doctor, who may suggest adjusting the dose or switching to another medication. Doctors may also recommend regular appointments to check for signs of more serious side effects.

Is methotrexate a chemotherpy drug?

It is essential to understand that doctors typically prescribe DMARDs such as methotrexate at a much lower dosage for people with RA than for those with cancer.

Only when doctors prescribe these drugs at a higher dosage to treat cancer do they consider the treatment chemotherapy.

What is the best DMARDs for rheumatoid arthritis?

The best DMARD medication may vary for each person with RA. The most common DMARD rheumatologist prescribe is methotrexate.

In some cases, a combination of different DMARDs or another class of medication may be appropriate.

What is the safest drug for rheumatoid arthritis?

The American Academy of Rheumatology recommends methotrexate as a first-line treatment for moderate-to-severe RA. For mild disease, other medications such as sulfasalazine may be appropriate and cause fewer potential side effects.

Can chemotherapy cause rheumatoid arthritis?

There are situations in which a person who has cancer receives chemotherapy to treat the disease and develops a type of inflammatory arthritis as a result. This is called post-chemotherapy rheumatism and can present like RA. However, it is not RA.