Etanercept is used for:treating moderate to severe forms of ankylosing spondylitis (as), juvenile arthritis, plaque psoriasis, and rheumatoid and psoriatic arthritis. etanercept may be used alone or with other medicines. it may also be used for other conditions as determined by your doctor.etanercept is a tnf blocker. it works by blocking a protein (tnf-alpha) found in the body that causes inflammation.