Hyalgan vs Synvisc: Differences and Similarities

Osteoarthritis is a degenerative condition that mainly affects the joints.  Affecting millions of patients around the world, it is the most common type of arthritis. The condition often causes severe pain, which tend to worsen over time. The pathophysiology of osteoarthritis is characterized by the loss of cartilage in the joint. In healthy individuals, cartilage functions as a protective cushion, helping the joints to work smoothly. The depletion of hyaluronic acid in the joint results in increased friction between the bones, ultimately causing knee stiffness and pain. While osteoarthritis can be highly deliberating, there are a number treatment modalities that can provide pain relief. For example, viscosupplements such as Hyalgan and Synvisc are able to provide symptomatic relief, helping to alleviate knee pain.

What is viscosupplementation?

Viscosupplementation is a type of treatment that cushions the joints. It often comes in the form of a gel-like fluid and is supplied as injectable. The fluid functions as a shock absorber, lubricating the joints. This helps to reduce knee pain while improving the mobility of patients. Synvisc and Hyalgan are some of the most popular viscosupplements used in the treatment of osteoarthritis.

What are the similarities between Hyalgan and Synvisc?

Hyalgan and Synvisc are only available as brand name products. Synvisc is developed by Sanofi S.A., a multinational pharmaceutical corporation based in Paris, France. Hyalgan, on the other hand, is a product of the Italy-based Fidia Farmaceutici S.p.A. Both drugs contain hyaluronic acid (a natural compound commonly found in the joint and skin) as the active ingredient.

More specifically, Synvisc contains hylan GF-20, while Hyalgan consists of sodium hyaluronate. Hyalgan and Synvisc act through a similar mechanism of action by supplementing the degraded synovial fluid. This helps to lubricate and cushion the knee joint, thereby restoring joint function and mobility. Currently, Hyalgan and Synvisc are being used as second-line therapies. It is recommended to use pain killers, physical therapy and/or weight reduction (which are the mainstay of osteoarthritis treatment) before using viscosupplements like Hyalgan and Synvisc. For patients who fail to obtain adequate pain relief, Hyalgan and Synvisc serve as the perfect alternative to these conservative treatments. Both formulations are clinically proven to be effective and safe in relieving knee pain associated with osteoarthritis. Hyalgan and Synvisc are administered through direct injection into the cavity that surrounds the knee joint. The injections should be performed by certified practitioners in a clinic. Be aware that neither Hyalgan nor Synvisc can provide instant pain relief.

What are the differences between Hyalgan and Synvisc?

Despite their similarities, there are some fundamental differences between Hyalgan and Synvisc. The ingredients of both injections are sourced from rooster combs. However, the hyaluronic acid in Synvisc has undergone chemical modification; therefore, it has an increased molecular weight. In contrast, Hyalgan is not chemically modified. In theory, injections with a higher molecular weight can better mimic the natural lubricants in the joints. Having said that, it is unclear if Synvisc is indeed more effective than Hyalgan clinically. In general, Hyalgan requires 1 injection per week for 5 weeks, whereas Synvisc requires 1 injection every week for 3 weeks. Generally, the duration of action for both injections is estimated to be 6 months. Regardless, some studies have suggested that the pain-relieving effects of Synvisc could last longer between treatments compared to Hyalgan (possibly due to the difference in their chemical properties).  

Side effects of Hyalgan and Synvisc

The side effect profiles of Hyalgan and Synvisc are very similar. Both of them have a risk of causing swelling, redness and pain at the site of injection.

The bottom line

The risk of developing osteoarthritis knee pain inevitably increases with advancing age. Apart from first line treatments such as oral analgesics and physical therapy, Hyalgan and Synvisc can be used as symptomatic treatments of osteoarthritis. They are especially useful in patients who respond inadequately to conventional treatments. Acting as viscosupplements, they have shown excellent results in reducing joint pain. Plus, both formulations have excellent safety profiles and are associated with a minimal risk of side effects. Hyalgan and Synvisc effectively alleviate knee pain, dramatically improving the quality of life of patients.