Etanercept is an injectable drug that is used for treating rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and plaque psoriasis.

It works by blocking tumor necrosis factor alpha (TNF alpha). Other drugs that block TNF alpha include adalimumab (Humira), certolizumab (Cimzia), golimumab (Simponi), and infliximab (Remicade)

TNF alpha is a protein that the body produces during when there is inflammation, the body's reaction to injury. TNF alpha promotes inflammation and its associated fever and signs (pain, tenderness, and swelling) in several inflammatory conditions including rheumatoid arthritis and ankylosing spondylitis. Etanercept is a synthetic (man-made) protein that binds to TNF alpha. It thereby acts like a sponge to remove most of the TNF alpha from the joints and blood. This prevents TNF alpha from promoting inflammation and the fever, pain, tenderness, and swelling of joints in patients with rheumatoid or psoriatic arthritis and ankylosing spondylitis. Etanercept prevents the progressive destruction of the joints in patients with rheumatoid arthritis and the arthritis of psoriasis. The FDA approved etanercept in November 1998.