Synvisc injections: doses, uses, and side effects

last updated: Mar 02, 2022

4 min read

Synvisc is a medication that healthcare providers use to help people with knee pain brought on by osteoarthritis who have not responded well to other treatments. Here's what you should know about Synvisc, including its uses, side effects, and cost.


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What is Synvisc?

Synvisc, Synvisc One, hylan G-F 20, or hyaluronic acid are all names for a thick, elastic fluid meant to mimic a naturally occurring substance in your joints called hyaluronan (Sanofi-Aventis, 2014). 

Hyaluronan is present in very high amounts in your joints. It acts as a joint lubricant and shock absorber and is necessary for your joints to bend and straighten smoothly. When age or medical conditions cause a loss of hyaluronan, you might experience joint pain or stiffness (Sanofi-Aventis, 2014).

When this pain or stiffness occurs—and other treatments have failed—your healthcare provider may recommend a type of treatment called viscosupplementation. This is when your healthcare provider injects a gel-like medication—like Synvisc—directly into your joint space to help lubricate and cushion it, essentially supplementing the natural fluid that has been lost. These types of injections can provide pain relief in your joint and may help you move better (Sanofi-Aventis, 2014).

Synvisc is available by prescription only, and your healthcare provider must administer it. (Sanofi-Aventis, 2014).

Synvisc uses

Synvisc is approved by the U.S. Food and Drug Administration (FDA) to treat knee pain caused by a condition called osteoarthritis in people who have not gotten better with other treatments (Sanofi-Aventis, 2014). 

Osteoarthritis is a type of joint inflammation that happens when the protective cartilage covering the ends of your bones wears down, and you lose the fluid that normally cushions the joint when you move (Sanofi-Aventis, 2014). 

Other types of treatment that your healthcare provider may recommend before trying viscosupplement injections include (Sanofi-Aventis, 2014):

  • Tylenol (acetaminophen)

  • Over-the-counter or prescription non-steroidal anti-inflammatory drugs (NSAIDs)

  • Hot or cold therapy

  • Activity changes

  • Weight loss (if obesity is present)

  • Physical therapy or exercises

  • Special braces

  • Removal of fluid build-up in the knee

You should not use Synvisc if you're allergic to hyaluronan, sodium hyaluronate, or hyaluronic acid. You should also not use it when you have an active knee joint infection or a skin disease in the area of the injection site (Sanofi-Aventis, 2014).

Synvisc side effects

The most common side effects of Synvisc are temporary pain and swelling in the knee where you had your Synvisc injection. If you experience significant pain or swelling, you should tell your healthcare provider (Sanofi-Aventis, 2014). 

You should avoid strenuous activities (such as soccer, tennis, or jogging) or prolonged weight-bearing activities for approximately 48 hours after the injections. Your provider will tell you when it is safe to resume these activities (Sanofi-Aventis, 2014). 

Some less common adverse events reported after having a Synvisc injection include (Sanofi-Aventis, 2014):

  • Rashes

  • Hives or itching

  • Fast heartbeat

  • Feeling sick or dizzy

  • Trouble breathing

  • Swelling in your face, arms, or legs

  • Low blood platelets (rare)

Synvisc dosage

Your healthcare provider’s office—not a pharmacy—will supply your dose of Synvisc, and your healthcare provider will administer it (Sanofi-Aventis, 2014).

They will use a single-dose syringe to inject 2 ml of Synvisc directly into your knee joint (also called an intra-articular injection). A course of Synvisc consists of three of these injections, each one week apart into the same knee joint (Sanofi-Aventis, 2014). 

Synvisc One is the same medication but is a 6 ml injection that your healthcare provider only administers once. 

Synvisc warnings

Synvisc is considered very safe and effective for treating osteoarthritis of the knee. However, there are a few key things to keep in mind regarding using it safely (Sanofi-Aventis, 2014):

  • Your healthcare provider should not inject Synvisc into any place other than your knee joint. Injecting this medication into any other joint than the knee hasn't been shown to help arthritis. If they inject it outside of the knee joint, it may cause unwanted effects.

  • You shouldn't have an injection of Synvisc if your knee is severely inflamed at the time or to treat any other knee condition besides osteoarthritis.

  • The hyaluronan in Synvisc comes from chicken combs. Let your provider know if you have had an allergic reaction to bird proteins, feathers, or egg products.

  • We don't yet know if Synvisc is safe and effective to use if you are pregnant or lactating. Let your healthcare provider know if you are pregnant or breastfeeding before having any joint injections. 

  • There are no studies on the use of Synvisc in anyone 21 years of age or younger. So, researchers don't yet know if it is safe or effective for this population.

Synvisc interactions

Since Synvisc is injected directly into your joint, it doesn't have any listed interactions with oral medications. It also doesn't raise your blood sugar levels the way that steroid and cortisone injections used for osteoarthritis can (Sanofi-Aventis, 2014).

Medical researchers haven't studied the effects of using Synvisc at the same time as other types of injections in the knee. Using Synvisc simultaneously with other injections in the knee isn't recommended because we do not know if it is safe or effective (Sanofi-Aventis, 2014).

Synvisc cost

Your location and insurance coverage will affect the final price of a medication. Sometimes you can use discounts or coupons from the manufacturer to lower your cost.

The current average price for a single syringe of Synvisc One (a medication very similar to Synvisc but only requiring one dose) is $1,732.65 (GoodRx, 2022). Because Synvisc is one-third the dose of Synvisc One, it is typically less expensive.

You can't usually buy Synvisc and other types of viscosupplements through a pharmacy. Typically, your provider's office will purchase the medication from the manufacturer and administer it in their office. They may have different pricing due to being able to buy in bulk.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

March 02, 2022

Written by

Ellyn Vohnoutka, BSN, RN

Fact checked by

Steve Silvestro, MD

About the medical reviewer

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.