Cyclophosphamide is an immunosuppressive medicine, which means that it decreases the effects of your body's immune system. By interrupting the immune process, cyclophosphamide reduces inflammation and slows joint damage caused by rheumatoid arthritis. Cyclophosphamide is a disease-modifying antirheumatic drug (DMARD), which means it controls the progression of the disease. DMARDs are also called slow-acting antirheumatic drugs (SAARDs).
Why It Is Used
Cyclophosphamide is used for severe rheumatoid arthritis that has not responded to other treatments, especially when there are also complications such as inflammation of blood vessels (vasculitis).
How Well It Works
Cyclophosphamide has been found to be effective in treating serious complications of rheumatoid arthritis such as vasculitis. Because of its serious side effects, cyclophosphamide is most often reserved for use in people with severe rheumatoid arthritis that has not responded to other treatments.footnote 1
Side effects of cyclophosphamide are common and can include:
Nausea and vomiting.
Hair loss (alopecia).
Cessation of menstruation (amenorrhea) or early menopause.
Decreased sperm count (azoospermia).
Darkening of skin (hyperpigmentation).
Severe reactions can include:
Decreased bone marrow function and serious blood problems.
Bladder problems such as blood in the urine.
Because cyclophosphamide decreases the activity of your body's natural immune system, fever and chills are considered serious side effects that should be reported to your doctor immediately.
Cyclophosphamide increases the risk of infections such as herpes zoster (shingles). Prolonged use of cyclophosphamide is associated with an increased risk for some cancers, including bladder cancer.
If you take cyclophosphamide, you may have a slightly greater chance of getting cancer. This risk is small. But your doctor may check for cancer more often than if you did not take cyclophosphamide.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
Cyclophosphamide should not be used by women who are pregnant or trying to become pregnant. If you are a woman of childbearing age and are going to take cyclophosphamide, use some form of reliable birth control.
If you are taking cyclophosphamide, it is very important to drink plenty of fluids (around 3 quarts) each day to avoid bladder irritations.
Your doctor will schedule you for regular blood counts during treatment with cyclophosphamide.
Shah A, St. Clair EW (2012). Rheumatoid arthritis. In DL Longo et al., eds., Harrison's Principles of Internal Medicine, 18th ed., vol. 2, pp. 2738–2752. New York: McGraw-Hill.
The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.