What to Know About Erelzi (Etanercept-Szzs)

An inflammatory arthritis drug considered a biosimilar to Enbrel

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Erelzi (etanercept-szzs) is an anti-TNF agent. The injectable liquid drug works by blocking tumor necrosis factor (TNF), a type of protein in your blood that's involved in the systemic inflammation seen in rheumatoid arthritis (RA) and certain other inflammatory types of arthritis. Erelzi is considered a biosimilar to Enbrel (etanercept). Though approved by the U.S. Food and Drug Administration (FDA) in 2016 for the same conditions as Enbrel, Erelzi is not currently available in the United States.

Eticovo, an Enbrel biosimilar, is also FDA-approved but not available in the US. Benepali, another Enbrel biosimilar, is available in Europe and is not currently available in the U.S.

What's a Biosimilar?

In 1998, Enbrel became the first FDA-approved biologic drug for RA. Biologics are produced from living organisms or components of living organisms. A biosimilar is a biological product that's highly similar to the original FDA-approved biologic with no clinically meaningful differences in safety and effectiveness.

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Woman making injection with syringe pen

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Erelzi is FDA-approved for the treatment of five conditions:

  • Rheumatoid arthritis (moderately to severely active): To reduce signs and symptoms, inhibit the progression of structural damage, and improve physical function. May be used alone or combined with methotrexate.
  • Psoriatic arthritis (PsA): To reduce signs and symptoms, inhibit the progression of structural damage of active cases, and improve physical function. It can be combined with methotrexate in people for whom methotrexate alone doesn't adequately improve symptoms.
  • Ankylosing spondylitis (AS, active): To reduce signs and symptoms.
  • Plaque psoriasis (PsO, chronic moderate-to-severe): For adults who are candidates for systemic therapy or phototherapy.
  • Juvenile idiopathic arthritis (JIA), polyarticular (moderately to severely active): To reduce signs and symptoms in children 2 years or older.

Healthcare providers also prescribe Erelzi for other types of arthritis or autoimmune diseases off-label for indications that are not FDA-approved.

Before Taking

Depending on the condition and severity, Erelzi may be used as a first-line treatment or a second-line treatment.

For example, it can be used as monotherapy for people treating ankylosing spondylitis or in combination with methotrexate for treating rheumatoid arthritis.

Precautions and Contraindications

While Erelzi is considered safe and effective in general, some people shouldn't take this drug.

The main contraindications are if you have:

  • An active infection
  • A latent infection
  • Congestive heart failure
  • A demyelinating neurologic disease like multiple sclerosis
  • Uveitis

Severe allergic reaction is possible with this drug. Don't take Erelzi if you're allergic to etanercept or any of its inactive ingredients.

You should also be cautious about taking Erelzi if you have:

  • Hepatitis B: If you've previously had a hepatitis B infection, be sure your healthcare provider knows. You'll need to be carefully monitored while taking Erelzi.
  • Tuberculosis (TB): If you have a history of TB exposure or active TB, this drug can cause reactivation or worsen the infection.
  • Pregnancy: Studies have shown that small amounts of Erelzi pass through the placenta, but the risk to your baby is so far unknown. If you're pregnant or trying to conceive, discuss the risks and benefits of the drug with your healthcare providers.
  • Breastfeeding: Limited research shows that small amounts of Erelzi can get into breastmilk, and that breastfed babies may absorb minimal amounts. Thus far, no research exists about the possible impact on the baby. If you're breastfeeding or planning to, be sure you talk about this with your medical team.
  • Children: The drug in Erelzi hasn't been studied in children under 2 years old.
  • Diabetes: Erelzi may cause low blood sugar (hypoglycemia) in some people. If you have diabetes, you may need to reduce your diabetes medication. Be sure to monitor your levels closely and talk to your healthcare provider before making any changes.

Biosimilars and biologics may have minor differences in their inactive ingredients, which may affect you if you have dietary restrictions or certain medical conditions.

The inactive ingredients in Erelzi include:

  • Sodium citrate
  • Sucrose
  • Sodium chloride
  • Lysine
  • Citric acid

Other Biosimilars for Systemic Inflammation

Several biosimilars used for treating diseases involving systemic inflammation are on the market. Your healthcare provider may try several drugs from this list, alone or in combination with methotrexate or other biologics/biosimilars.

Biologic Biosimilar Drug
Humira Amgevita, Imraldi, Halimatoz, Hyrimoz, Hefiya, Julio, Idacio, Kromeya Adalimumab
Remicade Inflectra, Renflexis, Ixifi, Avsola Infliximab
MebThera Blitzima, Ritemvia, Rituzena Rixathon, Riximyo, Truxima Rituximab

Humira, Remicade, and their biosimilars are TNF blockers. MabThera and its biosimilars alter your immune system's number of B-cells, which are part of the inflammatory response.

Adalimumab biosimilars are not currently available in the U.S.


Erelzi is administered by subcutaneous injection, which means you give yourself a shot under the skin, not into a vein. It comes in single-use prefilled syringes of 25 milligrams (mg) or 50 mg, or in a prefilled 50 mg auto-injector pen.

For adults with RA, PsA, AS, or PsO, the typical dosage of Erelzi is 50 mg per week. If you're prescribed two 25-mg injections per week, your healthcare provider will tell you whether to take both doses at once or to take them on different days.

The dose for juvenile idiopathic arthritis is based on weight. For children 2 and older who weigh less than 63 kilograms (kg), which is about 139 pounds, the dose is 0.8 mg weekly per kg weekly with a maximum dose of 50 mg pr week. Children weighing more than that are given an adult dosage.

Note that this drug is given weekly, not daily. Taking too much Erelzi is dangerous, so be sure to follow the dosage information carefully.

If you miss a dose, take it as soon as you can and continue with your normal dosage schedule. Ask your healthcare provider or pharmacist if you have any questions about missed doses or interruptions to your dosage schedule.

All listed dosages are according to the drug manufacturer. Check your prescription and talk to your healthcare provider to make sure you are taking the right dose for you.

How to Take and Store

Erelzi needs to be stored in your refrigerator until just before it's used. Do not freeze it. Keep your medication in its original box to protect it from light.

Be sure to familiarize yourself with the instructions and with the syringes or auto-injector pen that you'll be using.

Before injecting:

  • Take the medication out of the fridge (but keep it in the blister package) about half an hour before you plan to use it so it can warm up to room temperature. Injecting medication that's cold can be painful.
  • Choose an injection site: front of thighs, lower abdomen (but not within 5 centimeters of your navel), outside of the upper arms (if someone else is giving you the injection)
  • Always wash your hands thoroughly before handling the syringe or pen.
  • Clean the injection site with an alcohol swab and allow the skin to dry on its own.
  • Remove the syringe or pen from its packaging.

To use the syringe:

  • Remove the needle cap.
  • Gently pinch the skin at the injection site.
  • Holding the needle at a 45-degree angle to the skin, insert the needle fully.
  • While holding the syringe between your index and middle fingers, put your thumb on the plunger.
  • Slowly press down the plunger until it stops.
  • Hold it there for five seconds.
  • Carefully pull the needle straight out while keeping the plunger depressed.

To use the auto-injector pen:

  • Remove the cap only when you're ready to use the pen immediately (never more than five minutes before using).
  • Discard the cap; do not try to put it back on.
  • Hold the pen at a 90-degree angle to the skin.
  • Press firmly against the skin to start the injection.
  • You'll hear the first click when it starts; keep the pen firmly against the skin.
  • You'll hear a second click when the injection is almost done; keep the pen in position.
  • Look for the green indicator to see when the injection is complete.
  • Remove the pen.

After the injection:

  • If there's any blood, place a cotton ball or gauze over the injection site and hold it for 10 seconds.
  • Do not rub the site.
  • Cover the site with an adhesive bandage if necessary.
  • Dispose of the syringe/pen in a closable, puncture-resistant sharps container.

Side Effects

There are side effects and adverse events associated with Erelzi.


The most common adverse events associated with etanercept are:

  • Infections
  • Injection site reactions
  • Diarrhea
  • Rash


Based on clinical studies and postmarketing experience, the most serious adverse events associated with etanercept include:

People with symptoms of pancytopenia or aplastic anemia should seek medical attention and consider stopping Erelzi.

Warnings and Interactions

Erelzi has black-box warnings about serious infections and malignancies (cancer). Black-box warnings are the FDA's most serious warnings about drug dangers.

The warning about serious infections that can result while on this drug reads: "Patients treated with etanercept products are at increased risk for developing serious infections that may lead to hospitalization or death."

However, it should be noted that most people who developed these infections were also taking methotrexate, corticosteroids, or other immunosuppressants in addition to etanercept.

Reported infections include:

  • Tuberculosis, including reactivations
  • Invasive fungal infections
  • Opportunistic bacterial, viral, and other infections such as legionella and listeria

Your healthcare provider should monitor you for infection, especially if you've previously had tuberculosis. Be sure to report any diagnosed or suspected infection to your healthcare provider right away while you're on Erelzi. If you develop a serious infection or sepsis, Erelzi should be discontinued promptly, but only after speaking with your healthcare provider.

Lymphoma and other cancers have been linked to TNF blockers, including etanercept, in children and adolescents. Some of these cases have been fatal.

If you have any concerns about your child's health while they're on this drug, or before they begin taking it, bring it up with their healthcare provider.

Drug Interactions

Sometimes, a drug can have harmful interactions with other drugs.

Studies suggest that people treated with etanercept should avoid:

Talk to your healthcare provider about safe alternatives to live vaccines.

Make sure your healthcare provider knows about any drugs you're taking, including over-the-counter drugs, herbal products, and nutritional supplements. Your pharmacist is also a good resource when it comes to spotting potentially dangerous interactions.

Discontinuing Erelzi

You may need to go off of Erelzi temporarily due to illness or surgery, or permanently due to side effects or allergic reactions.

You don't need to taper off of etanercept as you do some drugs; it can be stopped immediately. However, do not do this without your healthcare provider's approval.

If your healthcare provider advises you to go off Erelzi temporarily, talk to them about how soon you should start taking it again.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. Food and Drug Administration news release. FDA approves erelzi, a biosimilar to Enbrel.

  2. Berthelsen BG, Fjeldsøe-Nielsen H, Nielsen CT, Hellmuth E. Etanercept concentrations in maternal serum, umbilical cord serum, breast milk and child serum during breastfeedingRheumatology (Oxford). 2010;49(11):2225–2227. doi:10.1093/rheumatology/keq185

  3. Funakubo Asanuma Y. Nihon Rinsho Meneki Gakkai Kaishi. Management of rheumatoid arthritis medications and pregnancy. 2015;38(1):45–56. doi:10.2177/jsci.38.45

  4. Pfeifer EC, Saxon DR, Janson RW. Etanercept-induced hypoglycemia in a patient with psoriatic arthritis and diabetesJ Investig Med High Impact Case Rep. 2017;5(3):2324709617727760. doi:10.1177/2324709617727760

  5. U.S. Food and Drug Administration: AccessData. Rituxan (rituximab) label.

Additional Reading

By Carol Eustice
Carol Eustice is a writer covering arthritis and chronic illness, who herself has been diagnosed with both rheumatoid arthritis and osteoarthritis.