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 and does not recommend mixing with any other drug or chemical.
Pharmacology - 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 inflammation by reducing concentrations of prostaglandin E2 (released in response to joint injury) and increases hyaluronate 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 acute trauma but without the presence of degradative enzymes.
It is also approved for the control of signs associated with non-infectious degenerative and/or traumatic arthritis in dogs.
Pharmacokinetics - PSGAG is deposited in all layers of articular cartilage and is preferentially taken up by osteoarthritic cartilage. When administered IM, articular levels will with time exceed those found in the serum. Peak joint levels are reached 48 hours after IM injection, and persist for up 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 no contraindications for IM use of the drug, the drug should not be used in place of other therapies in cases where infection is present or suspected, or in place of surgery or joint immobilization in cases where 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 in breeding animals (the manufacturer does not recommend use in breeding animals).
Adverse Effects/Warnings - Adverse effects are unlikely when using the IM route. Intraarticular administration may cause a post-injection inflammation (joint pain, effusion, swelling and associated lameness) secondary to sensitivity reactions, traumatic injection technique, overdosage, number or frequency of injections. Treatment consisting of anti-inflammatory drugs, cold hydrotherapy, and rest is recommended. Although rare, joint sepsis secondary to injection is also potentially 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 to horses twice weekly for 6 weeks revealed no untoward toxic effects. Approximately 2% of horses receiving overdoses (up to 1250 mg) IA showed transient symptoms associated with joint inflammation.
Drug Interactions - While specific drug interactions have not been detailed to date, using this product in conjunction with either steroids or non-steroidal antiinflammatory agents could mask the signs 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 use together with caution.
a) For IM administration: 500 mg IM (of IM product) every 4 days for 28 days. Thoroughly cleanse injection site before injecting. Do not mix with other drugs or chemicals. (Package Insert- Adequan® I.M.)
For intra-articular administration: 250 mg (of IA product) IA once a week for 5 weeks. Joint area should be shaved, and cleansed as if a surgical procedure, prior to injecting. Do not mix with other drugs or chemicals. (Package Insert- Adequan® I.M.)
b) For IM injection: 500 mg IM every 3-4 days for a minimum of 4 and preferably, 7 treatments.
For intra-articular injection: As above; author recommends adding 125 mg of amikacin for injection into the A injection to reduce potential for infection. (Nixon 1992)
Monitoring Parameters - Efficacy and joint inflammation/infection if administered IA.
Client Information - The IA product must be administered by veterinary professionals; the IM product could, with proper instruction be administered by the owner.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times -
Polysulfated glycosaminoglycan for Intra-Articular Injection 250 mg/ml in 1 ml glass ampules or 1 ml single use vials, boxes of 6; Adequan® I.A. (Luitpold); (Rx) Approved for use in horses (not in those intended for food).
Polysulfated glycosaminoglycan for Intra-Muscular Injection 100 mg/ml in 5 ml glass ampules or 5 ml vials, boxes of 4; Adequan® I.M. (Luitpold); (Rx) Approved for use in horses (not in those intended for food).
Polysulfated glycosaminoglycan for IM Injection 100 mg/ml; Adequan® Canine (Luitpold); (Rx) Approved for use in Dogs.
Human-Approved Products: None
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