Interleukin antagonists are used to treat conditions such as rheumatoid arthritis, psoriasis, and asthma. They also have other uses, such as managing inflammatory bowel disease and COVID-19. These medications work by blocking the action of specific interleukins, which are proteins that can cause inflammation and other immune responses in your body. Interleukin antagonists typically come as injections and infusions. There are many examples available, including Stelara (ustekinumab), Bimzelx (bimekizumab), Nucala (mepolizumab), and more.