GENERIC NAME: etanercept

BRAND NAME: Enbrel

DRUG CLASS AND MECHANISM: Etanercept is an injectable drug that blocks tumor necrosis factor alpha (TNF alpha) and is used for treating rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis. TNF alpha is a protein that the body produces during the inflammatory response, the body's reaction to injury. TNF alpha promotes the 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 molecules 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 reduces the signs and symptoms of rheumatoid arthritis, the arthritis of psoriasis, and ankylosing spondylitis.  It prevents the progressive destruction of the joints in patients with rheumatoid arthritis and the arthritis of psoriasis.

GENERIC AVAILABLE: No

PRESCRIPTION: Yes

PREPARATIONS: White preservative-free powder in 25 mg vials. Before injection, etanercept is mixed with 1 milliliter of sterile water to form a clear colorless solution. 50 mg/mL prefilled syringe containing 1 mL.

STORAGE: Sterile powder and pre-filled syringes should be refrigerated at 2-8°C (36- 46°F). Reconstituted solutions made from the powder should be used as soon as possible but may be stored in the vial at 2-8°C (36-46°F) for up to six hours.

PRESCRIBED FOR: Etanercept is used as primary treatment to reduce the pain, swelling and tenderness of joints resulting from moderate to severe rheumatoid arthritis in adults. It also may be used when rheumatoid arthritis has not adequately responded to other drugs (called disease-modifying medicines for rheumatoid arthritis).  Etanercept can be used in combination with methotrexate in patients who do not respond adequately to methotrexate alone.

Etanercept also is used to reduce the signs and symptoms of moderately to severely active, polyarticular-course, juvenile rheumatoid arthritis in patients who have had an inadequate response to one or more disease-modifying medicines.

Etanercept is approved for the treatment of ankylosing spondylitis and the arthritis of psoriasis. It can prevent the progressive destruction of the joints in patients with psoriatic arthritis.  Etanercept can improve physical function in patients with psoriatic arthritis. It also is reported to be of benefit in psoriasis, and uveitis.

Etanercept is not recommended for persons with preexisting disease of the central nervous system (brain and/or spinal cord) or for those with multiple sclerosis, myelitis, or optic neuritis.

DOSING: Etanercept is injected under the skin. Adults usually inject 25mg twice weekly. Children 4 to 17 years old should receive 0.4mg/kg (maximum 25mg) twice weekly. Etanercept has not been studied in children younger than 4 years.

DRUG INTERACTIONS: Drug interaction studies have not been conducted. Because etanercept may reduce the response of the immune system, etanercept should not be administered with live vaccines.

PREGNANCY: Studies have not been conducted in pregnant women. Etanercept is not recommended in pregnant women.

NURSING MOTHERS: It is unknown whether etanercept is excreted in human breast milk. Etanercept is not recommended in nursing women.

SIDE EFFECTS: The most common side effects are mild to moderate itching, pain, swelling and redness at the site of injection. Headache, dizziness, nasal and throat irritation also occur.

TNF alpha has an important role in the responses of the immune system to infections. Thus, blocking the action of TNF alpha with etanercept may worsen or increase the occurrence of infections, and patients with serious infections should not receive etanercept. Moreover, etanercept should be discontinued if a patient develops a serious infection. It is not initiated in patients with active infections or allergy to its components. In addition, children should receive their recommended immunizations before treatment with etanercept. Etanercept should be used with caution in patients prone to infection, such as those with advanced or poorly controlled diabetes.

Some reported associated conditions may or may not be related to etanercept. Since etanercept has been on the market, there have been reports of multiple sclerosis, myelitis, optic neuritis in patients using the drug. Etanercept is not recommended for persons with preexisting disease of the central nervous system (brain and/or spinal cord) or for those with multiple sclerosis, myelitis, or optic neuritis. Additionally, rare cases of seriously low blood counts (pancytopenia) have been reported in patients using etanercept.

Since etanercept is a relatively new drug, there is limited information on long-term risks.

Reference: FDA Prescribing Information