POLYSULFATED GLYCOSAMINOGLYCAN (PSGAG)

Chemistry - Polysulfated glycosaminoglycan (PSGAG) is chemically similar to natural mucopolysaccharides found in cartilaginous tissues. PSGAG is reportedly an analog of heparin.

Storage, Stability, Compatibility

Commercial products should be stored in a cool place 8-15°C(46-59°F). The manufacturer recommends discarding the unused portion from a vial or ampule anddoes not recommend mixing with any other drug or chemical.

Pharmacology - POLYSULFATED GLYCOSAMINOGLYCAN (PSGAG)

In joint tissue, PSGAG inhibits proteolytic enzymes that can degrade proteoglycans (including naturally occurring glycosaminoglycans), thereby preventing or reducing decreased connective tissue flexibility, resistance to compression and resiliency. By acting as a precursor, PSGAG also increases the synthesis of proteoglycans. PSGAG also reduces inflammationby reducing concentrations of prostaglandin E2 (released in response to joint injury) and increaseshyaluronate concentrations in the joint, thereby restoring synovial fluid viscosity.
Uses, Indications - PSGAG administered either IM or IA is indicated for the treatment of non-infectious and/or traumatic joint dysfunction and associated lameness of the carpal joints in horses.
Some studies have indicated that PSGAG is much less effective in joints where there has been acutetrauma but without the presence of degradative enzymes.
It is also approved for the control of signs associated with non-infectious degenerative and/ortraumatic arthritis in dogs..

Pharmacokinetics - POLYSULFATED GLYCOSAMINOGLYCAN (PSGAG)

PSGAG is deposited in all layers of articular cartilage and is preferentiallytaken up by osteoarthritic cartilage. When administered IM, articular levels will with time exceedthose found in the serum. Peak joint levels are reached 48 hours after IM injection, and persist forup to 96 hours after injection.

Contraindications, Precautions, Reproductive Safety

PSGAG is contraindicated for intra-articular administration in patients hypersensitive to it. While the manufacturer states there are nocontraindications for IM use of the drug, the drug should not be used in place of other therapies incases where infection is present or suspected, or in place of surgery or joint immobilization in caseswhere indicated.
Some clinicians feel that PSGAG should not be used within one week of arthrotomy in the dog, because it may cause increased bleeding. This effect apparently has not been confirmed in the literature however.
Reproductive studies have apparently not been performed; use with caution during pregnancy or inbreeding animals (the manufacturer does not recommend use in breeding animals).

Adverse Effects, Warnings

Adverse effects are unlikely when using the IM route. Intraarticularadministration may cause a post-injection inflammation (joint pain, effusion, swelling andassociated lameness) secondary to sensitivity reactions, traumatic injection technique, overdosage, number or frequency of injections. Treatment consisting of anti-inflammatory drugs, coldhydrotherapy, and rest is recommended. Although rare, joint sepsis secondary to injection is alsopotentially possible; strict aseptic technique should be employed to minimize its occurrence.
In dogs, a dose-related inhibition of coagulation/hemostasis has been described.
Overdosage, Acute Toxicity - Doses five times those recommended (2.5 grams) given IM tohorses twice weekly for 6 weeks revealed no untoward toxic effects. Approximately 2% of horsesreceiving overdoses (up to 1250 mg) IA showed transient symptoms associated with jointinflammation.

Drug Interactions

While specific drug interactions have not been detailed to date, using thisproduct in conjunction with either steroids or non-steroidal antiinflammatory agents could mask thesigns and symptoms associated with septic joints.
There is some concern that since PSGAG is a heparin analog that it should not be used in conjunction with other NSAID's or other anticoagulants. Clinical significance is unclear, but usetogether with caution.