Orencia (abatacept) is a medication used to treat rheumatoid arthritis in adults. It inhibits T cells, reducing inflammation and pain caused by autoimmune responses. It is administered through an injection and given twice a month. There are potential side effects such as headache and nausea, and it is not recommended for people with certain medical histories. While the medication can be expensive, there are programs available to help reduce costs. Overall, Orencia has been successful in improving joint function and is a valuable treatment option for patients with rheumatoid arthritis.