Yes, Stelara (ustekinumab) is an immunosuppressant. It is approved to treat certain forms of psoriasis, psoriatic arthritis and moderate to severe Crohn's disease and ulcerative colitis.

It works by blocking the effects of two different cytokines, interleukin-12 and interleukin-23. Cytokines are substances released by cells in the immune system that signal other immune cells to grow, respond or release other substances. They all work together to help the body prevent or fight infection. Some diseases, such as psoriasis and inflammatory bowel disease, are thought to be a result of an improper or exaggerated response of the immune system.

Because it is an immunosuppressant, people on Stelara may be more at risk for developing infections of any type; bacterial, viral or fungal. You should not start Stelara if you have a current infection. Your health care provider may perform tests to confirm this before prescribing the medicine. This includes checking you for tuberculosis.

If you develop any symptoms of an infection, you should notify your health care provider right away. If you do develop an infection while on the medicine, your health care provider may have you stop taking it for a time.

Stelara may be used in combination with other types of immunosuppressant drugs.