Etanercept is a medication that is used for treating autoimmune diseases, such as rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, psoriasis, and refractory asthma.
Etanercept is the generic name, and the trade name is Enbrel.
Etanercept is a tumor necrosis factor (TNF) inhibitor, which means it interferes with TNF.
TNF is made by the body's immune system. It encourages an inflammatory response that is needed for the body to fight disease. But, this stimulation of the inflammatory response is also what causes many of the clinical problems linked to autoimmune diseases. People with these immune disorders have too much TNF in their bodies.
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How does etanercept work?
TNF inhibitors reduce the inflammatory response that causes joint pain in conditions such as rheumatoid arthritis.
The role of TNF is to transport white blood cells to areas of inflammation. In doing so, it can make an inflammation worse.
Etanercept inhibits, or prevents, the action of TNF. In this way, the drug can reduce the body's inflammatory response.
The inflammatory response is a reaction in which the body releases various substances and chemicals that allow it to fight infections and other harmful cells.
Being able to stop the inflammatory response is useful when treating autoimmune diseases.
What does etanercept treat?
In the United States, etanercept has been licensed by the Food and Drug Administration (FDA) to treat a number of conditions.
This is a chronic, painful and progressive inflammatory disease that affects the joints and ligaments that normally allow a person's back to move and flex. It is estimated to affect between 0.2 percent and 0.5 percent of people in the U.S. It mostly affects the lower back, but it can affect the upper spine, chest, and neck.
Psoriasis is an autoimmune skin disease. In psoriasis, skin cells grow more rapidly than usual. It is a chronic, or long-term, condition. Plaque psoriasis is the most common type.
People with plaque psoriasis have raised areas of inflamed skin covered with silvery white scaly skin, or plaques. A flaky white buildup of dead skin cells collects on the plaques, and this is called scale. Plaque psoriasis can appear on any skin surface.
Etanercept can be used in cases of moderate to severe plaque psoriasis.
Most patients with psoriatic arthritis developed psoriasis first, and are later diagnosed with psoriatic arthritis.
Symptoms include inflammation of the skin, or psoriasis, and joints, which is arthritis. It may appear at any time, but usually between the ages of 30 and 50 years.
Juvenile rheumatoid arthritis
Also known as polyarticular juvenile idiopathic arthritis, moderate and severe cases of this condition can be treated with etanercept.
Juvenile rheumatoid arthritis is the most common chronic, rheumatic disease in children. It is a major cause of short-term and long-term disability. It causes chronic pain, stiffness, and swelling of the joints. In severe cases there may be joint damage and deformities.
It usually starts before the age of 16 years. Some form of juvenile arthritis is thought to affect between 70,000 and 100,000 American children under the age of 16 years.
Moderate to severe rheumatoid arthritis (RA)
Rheumatoid arthritis (RA) is a chronic, progressive, and disabling auto-immune disease that causes inflammation, or swelling, and pain in the joints, the tissue around the joints, and other organs in the human body.
It normally starts with the hands and feet. People with RA often feel generally unwell and tired.
How is etanercept used?
Etanercept cannot be swallowed, because the digestive system would destroy it. Patients normally take it once or twice weekly, as an injection. Patients can learn to inject themselves.
Etanercept comes in two separate formulations:
- A freeze-dried powder in 25 mg vials that is reconstituted with a diluting agent and then injected into the patient under the skin. Most patients can do this themselves.
- A pre-mixed liquid in 50 mg/ml syringes or auto-injector pens.
The duration of the therapy may be several months, as determined by the physician.
Cautions when taking etanercept
Etanercept can reduce the amount of TNF in the body, and reduce the damage that too much TNF may cause.
As a result, it can also reduce the capacity of the immune system to fight infections.
The Centers for Disease Control and Prevention (CDC) note that people who use TNF medications are at risk of a reactivation of latent TB infection.