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Enbrel® (etanercept) – TNF Inhibitor

Enbrel is a prescription medication classified as a biologic that is a tumor necrosis factor (TNF) inhibitor. Enbrel is used to treat ankylosing spondylitis (AS). Generally, in patients with AS, biologics are used when there is radiographic axial spondylitis (evidence of joint damage visible on imaging) and that has not been adequately managed with NSAIDs (non-steroidal anti-inflammatory drugs). Enbrel is also approved to treat rheumatoid arthritis, psoriatic arthritis, plaque psoriasis, and polyarticular juvenile idiopathic arthritis (JIA).1. Enbrel, unlike other anti-TNF’s, is not effective against uveitis or inflammatory bowel disease. The active ingredient in Enbrel is etanercept, a TNF inhibitor.

How does Enbrel work?

AS is a chronic inflammatory arthritis. In people with AS, there is chronic inflammation at the joints, primarily the joints in the spine but AS may also affect other joints in the body. In addition to the joints, many people with AS have inflammation in the locations (entheses) where the ligaments and tendons attach to the bone. This inflammation is called enthesitis and can cause “hot spots” of tenderness along the spine or along the back of the heel.2

Enbrel is a TNF inhibitor. TNF is a naturally occurring protein, called a cytokine, that is involved in the normal inflammatory response in the body. In people with AS, there is an excess or abnormal inflammatory response and elevated levels of TNF. Blocking TNF can help reduce the inflammation and help relieve the symptoms of AS.1,3

What are the possible side effects of Enbrel?

The most common side effects experienced by people taking Enbrel for AS include infections and injection site reactions. Because TNF is involved in the normal immune response of inflammation, taking a TNF blocker like Enbrel can make it harder to fight certain infections. Injection site reactions may include redness, itching, pain, or swelling at the site where Enbrel is administered.1

Serious side effects may occur with Enbrel. Some people have had serious infections while taking Enbrel, including tuberculosis (TB), bacterial sepsis, and invasive fungal infections. These serious infections may lead to hospitalization or death.1,3

There have been some cases of cancer in children and teenagers taking Enbrel. These cancers may lead to death. Children, teenagers, and adults taking Enbrel may have an increased risk of developing lymphoma or other cancers.1,3

This is not an exhaustive list of all potential side effects of Enbrel. For more information, patients should talk to their doctor about what to expect. Any new or worsening side effects should be reported to a doctor or healthcare professional.

Things to know about Enbrel

Before starting treatment with Enbrel, patients should talk to their doctors about all their medical conditions, especially if they1,3:

  • Have any signs of infection or are prone to frequent infections
  • Have any open cuts or sores
  • Have HIV, diabetes, or a weakened immune system
  • Tested positive for TB or have been in close contact with someone who has TB
    Were born in, lived in, or traveled to countries where there is an increased risk of TB (ask your doctor if you aren’t sure)
  • Live in areas of the US where known for fungal infections, including the Ohio and Mississippi Valley and the Southwest
  • Have any nervous system problems like seizures, multiple sclerosis, or Guillain-Barré syndrome
  • Have or have had heart failure
  • Have or have had hepatitis B
  • Have been around someone with chicken pox
  • Are scheduled to have surgery
  • Are scheduled to receive a vaccine
  • Are pregnant or plan to become pregnant or are breastfeeding

Patients should be tested for TB before beginning treatment with Enbrel.1

Before beginning treatment with Enbrel, patients should talk to their doctors about all medications (over-the-counter and prescription), vitamins, and supplements they are taking. Some medications or supplements may increase the risk of side effects if taken in combination with Enbrel.1,3

If an infection occurs while taking Enbrel, patients should contact their doctor. If the infection becomes serious, treatment with Enbrel may be stopped.1,3

Patients taking this medication should not receive live vaccines.1,3

During treatment with Enbrel, patients should be monitored for any possible heart problems, anemia, infection, and nerve damage.1

Dosing information

As a systemic medication, Enbrel goes throughout the whole body to treat symptoms of AS. It is administered as a subcutaneous (under the skin) injection. For AS, it is generally given once weekly.1 Patients should talk to their doctor about any questions on their dosing regimen.

Written by: Emily Downward | Last reviewed: February 2019
  1. Enbrel prescribing information. Available at https://www.pi.amgen.com/~/media/amgen/repositorysites/pi-amgen-com/enbrel/enbrel_pi.pdf. Revised November 2017. Accessed 1/8/19.
  2. Ankylosing spondylitis. Mayo Clinic. Available at https://www.mayoclinic.org/diseases-conditions/ankylosing-spondylitis/symptoms-causes/syc-20354808. Accessed 1/8/19.
  3. Enbrel product website. Available at https://www.enbrel.com/ankylosing-spondylitis/how-enbrel-works-as. Accessed 1/8/19.