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Zilretta Injection

Generic name: triamcinolone acetonide (injection) [ TRYE-am-SIN-oh-lone ]
Drug class: Glucocorticoids

Medically reviewed by Judith Stewart, BPharm. Last updated on Aug 18, 2023.

What is Zilretta injection?

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

Zilretta is for injection directly into the knee and and should not be administered by any other injection method.

Zilretta injection is not suitable for use in small joints, such as the hand.

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

Zilretta side effects

Get emergency medical help if you have signs of an allergic reaction to Zilretta: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Zilretta may cause serious side effects. Call your doctor at once if you have:

Certain side effects may be more likely with long-term use or repeated doses of Zilretta injection.

Steroids can affect growth in children. Tell your doctor if your child is not growing at a normal rate while using this medicine.

Common Zilretta side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


You may not be able to receive Zilretta if you have a fungal infection, or a condition called idiopathic thrombocytopenic purpura (ITP).

Before taking this medicine

You should not be treated with Zilretta if you are allergic to triamcinolone.

You may not be able to receive Zilretta injection if you have a fungal infection, or a condition called idiopathic thrombocytopenic purpura (ITP).

Tell your doctor if you have ever had:

Tell your doctor if you are pregnant or breastfeeding.

How is Zilretta injection given?

Zilretta injection is administered by a health professional as a single extended-release injection of triamcinolone acetonide directly into the knee joint.

Triamcinolone can weaken (suppress) your immune system, and you may get an infection more easily. Call your doctor if you have unusual bruising or bleeding, or signs of infection (fever, weakness, cold or flu symptoms, skin sores, diarrhea, frequent or recurring illness).

Your doctor may instruct you to limit your salt intake while you are receiving Zilretta injection. You may also need to take potassium supplements. Follow all instructions.

Triamcinolone can affect the results of certain medical tests. Tell any doctor who treats you that you are using Zilretta.

Dosing Information

Usual Adult Dose of Zilretta for Osteoarthritis:
Extended-release: 32 mg/5 mL:
For Osteoarthritic Knee Pain only: 32 mg as a single intra-articular injection
The safety and efficacy of repeat administration has not been evaluated

If an excessive amount of synovial fluid is present in the joint, aspirate some (not all) to provide pain relief and prevent undue dilution of the steroid.
Zilretta is not suitable for use in small joints, such as the hand, it is only indicated for osteoarthritis of the knee.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for a scheduled Zilretta injection.

As Zilretta is used as a single dose, you will not be on a regular dosing schedule.

What happens if I overdose?

Since Zilretta is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

Using too much Zilretta is not likely to cause serious problems. However, long term use of high doses can lead to thinning skin, easy bruising, changes in body fat (especially in your face, neck, back, and waist), increased acne or facial hair, menstrual problems, impotence, or loss of interest in sex.

What should I avoid while receiving Zilretta injection?

After injection of Zilretta into the knee joint, avoid overusing that joint through strenuous activity or high-impact sports. You could cause damage to the joint.

Avoid being near people who are sick or have infections. Call your doctor for preventive treatment if you are exposed to chickenpox or measles. These conditions can be serious or even fatal in people who are using triamcinolone.

Do not receive a "live" vaccine or a toxoid vaccine while using Zilretta, or you could develop a serious infection. Live vaccines include measles, mumps, rubella (MMR), polio, rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine. Toxoid vaccines include diphtheria-tetanus toxoid (DT or Td).

What other drugs will affect Zilretta injection?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Tell your doctor about all your current medicines. Many drugs can interact with triamcinolone, especially:

This list is not complete and many other drugs may affect Zilretta. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.


Flexion Therapeutics, Inc, 10 Mall Rd, Suite 301, Burlington, MA 01803, USA.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Zilretta only for the indication prescribed.

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