Orencia Powder for infusion is used in treating Rheumatoid arthritis and Juvenile idiopathic arthritis. It consists of Abatacept, which belongs to the TNF (Tumor necrosis factor) inhibitor class of drugs. Abatacept works by reducing the activity of these T-cells, which in turn reduces inflammation, pain, swelling and joint damage. Common side effects of this medication may include headache, nausea, cough, fever, sore throat, abdominal pain, diarrhoea, upper respiratory tract infections, tingling or numbness, dizziness, shortness of breath, pale skin, redness on the skin and arms, and injection site reactions.