This medication is used alone or with other medications to treat moderate to severe rheumatoid arthritis in adults. It is also used to treat rheumatoid arthritis in children (such as systemic juvenile idiopathic arthritis-SJIA, polyarticular juvenile idiopathic arthritis-PJIA). It helps to reduce pain and swelling due to rheumatoid arthritis. Tocilizumab belongs to a class of drugs known as Interleukin-6 (IL-6) blockers. It works by blocking IL-6, a substance made by the body that causes swelling (inflammation).