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Medically reviewed by Judith Stewart, BPharm. Last updated on May 11, 2022.

Generic Name: triamcinolone acetonide
Dosage Form: extended-release injectable suspension

What is Zilretta?

Zilretta is an extended-release corticosteroid approved to manage osteoarthritis knee pain.

The benefits and risks of repeat injections have not been demonstrated.

Who should not receive Zilretta?

You should not receive a Zilretta injection if you are allergic to corticosteroids, triamcinolone acetonide, or any other ingredient in Zilretta.

What possible side effects of corticosteroids could occur with Zilretta?

  • Rare serious allergic reactions
  • Effects in the injected knee such as infection (with pain, swelling and restricted motion) or joint damage
  • Increased chance of getting an infection, and a decreased ability to fight an infection
  • Effects on hormone production. These effects can be reversible
  • Elevated blood pressure, sodium and water retention, and potassium loss
  • Intestinal perforation if you have certain gastrointestinal disorders
  • Weakening of bones
  • Changes in behavior or mood disturbances
  • Increased pressure inside the eye

Zilretta side effects

In multiple clinical trials, the most common side effects seen in people taking Zilretta were joint pain, headache, joint swelling, back pain, sore throat and runny nose, upper respiratory tract infection, and bruising.

What should you tell your doctor BEFORE receiving a Zilretta injection?

Tell your doctor about all of the medications you are taking (including both prescription and over-the-counter medicines) and about any medical conditions, especially if you have high blood pressure, heart disease, ulcers, diverticulitis or other gastrointestinal disorders, kidney problems, diabetes, glaucoma, behavior or mood disorders, and/or infections.

What should you tell your doctor AFTER receiving a Zilretta injection?

Contact your doctor if you develop a fever or other signs of infection, have an increase in pain along with swelling of the injected knee, restriction of joint motion, or a general feeling of discomfort. Contact your doctor immediately if you are exposed to chicken pox or measles, or for any new or worsening changes in behavior or mood.

These are not all of the possible side effects with Zilretta or corticosteroid medications. Always contact your doctor if you have questions or experience any side effects.

What are the ingredients in Zilretta?

Active ingredient: triamcinolone acetonide
Inactive ingredients: sodium chloride, sodium carboxymethylcellulose and polysorbate-80

You are encouraged to report side effects to the FDA: Call 1-800-FDA-1088 (332-1088), or visit You may also report side effects to Flexion at 1-844-FLEXION (353-9466).

Popular FAQ

Topical clobetasol and triamcinolone are both classified as super-high to high potency topical corticosteroid (“steroid”) medicines used on the skin. They are used to treat skin conditions that are responsive to topical corticosteroids, such as dermatitis, eczema (atopic dermatitis) and serious allergic reactions. ​​Most products are available as a generic option. Continue reading

Which topical corticosteroid (“steroid”) product is best for you depends upon what skin condition you have, your symptoms and where it is located on your body. Other selection factors may include availability, cost and if the medicine is covered by your insurance. After examination, your doctor will be able to determine which topical steroid is best to treat your skin condition. Continue reading

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.