etanercept (Enbrel)

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.

What brand names are available for etanercept?

Enbrel

Is etanercept available as a generic drug?

No

Do I need a prescription for etanercept?

Yes

The most common side effects are:

• mild to moderate itching,
• pain,
• swelling and redness at the site of injection,
• headache,
• dizziness,
• nasal and throat.

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 such as tuberculosis, bacterial sepsis, invasive fungal infections (such as histoplasmosis), and other opportunistic infections (infections that occur primarily in patients with suppressed immune systems). Patients with serious infections should not receive etanercept, and etanercept should be discontinued if a patient develops a serious infection. Etanercept should be used with caution in patients prone to infection, such as those with advanced or poorly controlled diabetes. Children should receive their recommended immunizations before treatment with etanercept.

Some reported associated conditions may or may not be related to etanercept.

Other important side effects include:

• cancer,
• multiple sclerosis,
• myelitis, and
• optic neuritis.

For this reason, 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. New cases or worsening of congestive heart failure may occur.

Etanercept is injected under the skin.

• Adult rheumatoid arthritis, psoriatic arthritis, or ankylosing spondylitis: 50 mg weekly
• Plaque psoriasis: 50 mg twice weekly for 3 months, followed by 50 mg once weekly
• Juvenile rheumatoid arthritis: 0.8 mg/kg weekly, with a maximum of 50 mg per week

Because etanercept may reduce the response of the immune system, etanercept should not be administered with live vaccines. Combining etanercept with anakinra (Kineret) or abatacept (Orencia), drugs that also reduce the response of the immune system may increase the risk of serious infections.

Studies have not been conducted in pregnant women. Animal studies using doses 60-100 times human doses did not reveal toxicity to the fetus. Since animal studies are not always predictive of human response, etanercept is only used in pregnant women when there is a clear need.

It is unknown whether etanercept is excreted in human breast milk. Because of the risk of serious effects in the infant, a decision should be made whether to discontinue nursing or etanercept.

What preparations of etanercept are available?

25 mg multiple use vial; 25 or 50 mg prefilled syringe; 50 mg prefilled autoinjector.

How should I keep etanercept stored?

Sterile powder and pre-filled syringes should be refrigerated at 2 C to 8 C (36 F to 46 F). Reconstituted solutions made from the powder should be used as soon as possible but may be stored in the vial at 2 C - 8 C (36 F - 46 F) for 14 days.