Etanercept (Enbrel^®) can treat certain inflammatory conditions of the joints and skin by keeping the immune system from attacking the body. Some of these inflammatory conditions include rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and plaque psoriasis. The medication comes in an injection form that is taken once or twice a week. Prior to taking etanercept, be sure to tell your healthcare provider if you have multiple sclerosis, epilepsy, or congestive heart failure. As with any medication, there are potential side effects of etanercept, including reactions at the injection site, infections, and headaches.