Chemotherapy drugs are commonly used as cancer treatments due to their ability to kill cells that divide quickly. However, chemotherapy can also be used to treat autoimmune diseases such as inflammatory arthritis (rheumatoid arthritis and psoriatic arthritis) and systemic lupus erythematosus.

Disease-Modifying Antirheumatic Drugs

Chemotherapy drugs used for rheumatological diseases are known as disease-modifying antirheumatic drugs (DMARDs). DMARDs are specific drugs that help slow the progression of autoimmune diseases and prevent further joint damage. They target the exact cause of inflammation, which is usually caused by the body’s immune system attacking healthy cells.

Chemotherapy DMARDs help limit the number of immune cells made and the inflammatory mediators they release. They are commonly called immunosuppressive drugs because they suppress the immune system. DMARDs are given at lower doses for treating RA than when used for treating cancer.

Methotrexate

Rheumatrex or Trexall (methotrexate) is a first-line DMARD given to people with RA. It is effective, has few side effects, and is easy to take. Methotrexate can be given as a subcutaneous injection (just under the skin) or taken orally. It typically begins working within four to six weeks after treatment, and the dose can be easily adjusted as needed.

Methotrexate is often combined with other RA medications for more effective treatment, including nonsteroidal anti-inflammatory drugs (NSAIDs) such as Tylenol (ibuprofen) and Aleve (naproxen). Methotrexate can also be used in double therapy with another DMARD, such as:

• Azulfidine (sulfasalazine)
• Plaquenil (hydroxychloroquine)
• Imuran (azathioprine)
• Arava (leflunomide)
• Neoral (cyclosporine)

Triple therapy uses a combination of methotrexate, sulfasalazine, and hydroxychloroquine — a combination that may be as effective as using methotrexate with a biologic.

Cyclophosphamide

Cytoxan (cyclophosphamide) is used for treating severe RA that has not responded well to other treatments (known as refractory RA). It can also be used for treating other conditions associated with RA, such as vasculitis. Cytoxan can have serious risks, including infection and damage to cells in the bone marrow. Your doctor or rheumatologist will check your blood cell counts while you are taking this medication to help avoid negative side effects.

Cytoxan can be given by injection at a hospital or doctor’s office every one to four weeks, or it can be taken orally. The dosage changes from person to person, but it is typically based on body weight, height, and how well your kidneys work. It can take several weeks to see improvements, and even longer to feel the full effects of cyclophosphamide.

Azathioprine

Imuran (azathioprine) is an immunosuppressive drug used to treat RA and other autoimmune conditions. It works by preventing cells from making new DNA molecules, which causes them to stop dividing and die. It can also be used to dampen the immune system before an organ transplant to prevent the new organ from being rejected.

Imuran is given orally as a tablet in doses between 50 milligrams and 150 milligrams. You may notice that the medication begins working six to eight weeks after starting treatment, and it may take up to 12 weeks to feel the full effects.

Corticosteroids

Traditionally, when corticosteroids (also known as steroids) are used as treatment against cancer, they are considered chemotherapy drugs. They are also used in treating RA because they are fast-working and strong anti-inflammatory drugs. Corticosteroids mimic the shape and function of natural hormones found in the body that work to dampen the immune system.

Corticosteroids can be given in many ways, including by mouth or as intramuscular (IM) or intravenous (IV) injections. In some cases, corticosteroids can be injected directly into a joint to help treat joint pain at the source. Examples of corticosteroids include prednisone and methylprednisolone.

Side Effects of Chemotherapy Drugs

Chemotherapy drugs may come with a number of side effects. Most RA treatments using chemotherapy employ a lower dose of the drugs, and the side effects may be less severe than normal. Side effects can include:

• Hair loss
• Nausea
• Vomiting
• Fatigue
• Mouth sores
• Easy bleeding and bruising
• Fever
• Constipation
• Diarrhea

Chemotherapy drugs suppress the immune system and decrease the number of white blood cells in the body, which can put you at an increased risk of infection. The exact risk depends on which drugs are used, the dosage, your age, and any other underlying health conditions.

Chemotherapy drugs also have the potential to increase your risk of developing cancer. This rarely happens with RA drugs such as Imuran, Cytoxan, and methotrexate, but all three have been linked to a risk of developing lymphoma (a type of blood cancer). People with RA who take methotrexate are also more likely to develop lymphoma if they have been infected with the Epstein-Barr virus.

Chemotherapy drugs affect bone marrow cells, which are responsible for making new red blood cells, white blood cells, and platelets. With some treatments, your doctor or rheumatologist will run blood tests to check your blood cell counts.

Connect With Others Who Understand

On myRAteam, the social network for people with rheumatoid arthritis and their loved ones, more than 150,000 members come together to ask questions, give advice, and share their stories with others who understand life with RA.

Have you been given chemotherapy to treat your RA? Share your experience in the comments below, or by posting your story on myRAteam.