How Does Chemotherapy Help Arthritis?
In many rheumatic diseases, inflammation causes damage to parts of the body, such as what happens to the joints in rheumatoid arthritis. In most cases, inflammation results from autoimmunity, a malfunction of the immune system in which a person’s own tissues or organs are mistakenly attacked by the body’s immune system.
Chemotherapy slows cell reproduction and decreases certain products made by these cells, and, therefore, may help people with certain inflammatory and autoimmune diseases. Because of the suppressive effect of chemotherapy on autoimmunity, these drugs are sometimes called immunosuppressive drugs.
Types of Chemotherapy Drugs
There are quite a few chemotherapy drugs on the market, but only three are widely used in treating rheumatic diseases today. They are Methotrexate (Rheumatrex), Azathioprine (Imuran), and Cyclophosphamide (Cytoxan).
Methotrexate
Methotrexate is the chemotherapeutic drug most widely used by rheumatologists. It’s widely used for two main reasons; it is effective in treating rheumatoid arthritis and certain other rheumatic diseases (especially polymyositis and certain types of vasculitis or inflammation of blood vessels), and it is relatively safe. Most patients are able to take methotrexate by mouth in a single, weekly dose, although some patients prefer to take it as an injection once a week.
Azathioprine
Azathioprine has been used for many years as an immunosuppressive drug to prevent rejection in patients receiving kidney transplants. It is also used to suppress the abnormal immune response in some patients with vasculitis, systemic lupus erythematosus, rheumatoid arthritis, and vasculitis. However, patients should be aware that azathioprine has been linked to lymphoma, a cancer of the lymph nodes.
Cyclophosphamide
Cyclophosphamide is considerably more powerful and toxic than methotrexate and azathioprine. It is used to treat the most aggressive and dangerous rheumatic diseases, such as severe lupus and some forms of vasculitis. This drug directly attacks rapidly reproducing cells such as those in the immune system. Resting cells, that are not multiplying, can be affected if there is enough drug present. It is taken either by mouth or by injection.
What are the Side Effects of Chemotherapy Drugs?
Side effects of chemotherapy drugs are common, even though the doses are typically lower than the doses used to treat cancer. All of these drugs can suppress the formation of blood cells, resulting in anemia (low red blood cell count), leukopenia/neutropenia (low white blood cell count that may cause decreased resistance to infection), and thrombocytopenia (low platelet count that may cause impaired blood clotting).
In addition to those side effects, methotrexate and azathioprine can damage the liver, and cyclophosphamide can damage the urinary bladder lining and cause bleeding or cancer in the bladder lining. Cyclophosphamide also causes hair loss and sterility, while methotrexate and cyclophosphamide can damage the lungs.
Patients should remember that no drug is entirely safe, and it’s best to talk to one’s rheumatologist about the possible benefits of these drugs, as well as their side effects. The occurrence of side effects depends on the dose, type of medication, and length of treatment.
It is very important to have the appropriate follow-up exams and laboratory testing while taking chemotherapy drugs, as careful monitoring can minimize all of these risks.
