VetMedOsteoarthritis in dogs: intramuscular polysulfated glycosaminoglycan (Adequan) vs placebo — MAYBE (weak evidence) (the treatment made no difference)
In dogs with osteoarthritis, does intramuscular polysulfated glycosaminoglycan (Adequan) improve clinical signs vs placebo?
Shelf #187 · gate-verified and displayed under the developer's blinded-trial rule
MAYBE (weak evidence) (the treatment made no difference): The only genuine placebo-controlled clinical trial of intramuscular polysulfated glycosaminoglycan (PSGAG) found in dogs was null on its clinical comparison — and it was not, strictly, an osteoarthritis trial. De Haan 1994 was a double-blinded, randomised, controlled study in 84 evaluable adult dogs with HIP DYSPLASIA (111 dogs collected), comparing placebo with PSGAG at 2.2, 4.4 and 8.8 mg/kg intramuscularly every 3 to 5 days for eight injections: the 4.4 mg/kg group showed the greatest improvement in orthopedic scores and the placebo group the smallest, but the differences in clinical improvement between the four treatment groups were not statistically significant, and no local or systemic adverse reactions related to the drug were observed. That is the whole placebo-controlled clinical evidence base: one 1994 trial, in hip dysplasia rather than osteoarthritis generally, split four ways, with a null result. The only osteoarthritis-specific clinical record, Fujiki 2007, gave PSGAG to all 16 osteoarthritic dogs with no placebo or comparator group at all, so its before-and-after lameness improvement (12 of 16 dogs) cannot separate drug effect from time, handling or expectation. Pentosan polysulfate is a different product and its trials are not carded as PSGAG evidence. Drafted Nov 10, 2026 (VetMed build, topic #187); all figures from abstracts fetched and verified at drafting.
De Haan 1994: PSGAG 4.4 mg/kg improved most and placebo least, but differences between the four groups were NOT statistically significant
Double-blinded, controlled clinical study; randomised controlled trial (record's own wording and publication types)
Who: Dogs: adult dogs affected with hip dysplasia in a clinical setting; data were collected on 111 dogs and 84 met all criteria for inclusion, randomly assigned to placebo or polysulfated glycosaminoglycan at 2.2 mg/kg, 4.4 mg/kg or 8.8 mg/kg, administered intramuscularly every 3 to 5 days for a total of eight injections.
Result: Dogs that were given 4.4 mg/kg of PSGAG showed the greatest improvement in orthopedic scores, whereas dogs in the placebo group showed the smallest improvement; however, the differences in clinical improvement between the four treatment groups were not statistically significant. Response was analysed from changes in lameness, range of motion, and pain on manipulation of the hip joints. No local or systemic adverse reactions related to the drug were observed; adverse-reaction evaluation included complete blood cell count, blood urea nitrogen, creatinine, and physical examination.
Watch out: Population correction to the draft premise: this trial enrolled dogs with hip dysplasia, not osteoarthritis generally — it is carded because it is the only placebo-controlled clinical PSGAG trial in dogs found, and its result should not be silently transported to every osteoarthritic joint. Splitting 84 evaluable dogs across four arms leaves each dose group small, so the trial could miss a modest dose-specific effect; equally, the ordering (best dose in the middle) with a null overall test is the pattern expected from chance. This is a 1994 record: methods reporting is of its era, and no registry record exists.
de Haan JJ, Goring RL, Beale BS. Evaluation of polysulfated glycosaminoglycan for the treatment of hip dysplasia in dogs. Vet Surg. 1994;23(3):177-81. PMID: 8066981. Registry ID: none in the record. MeSH: Animals · Blood Cell Count/veterinary · Blood Urea Nitrogen · Creatinine/blood · Dogs · Dose-Response Relationship, Drug · Double-Blind Method · Female · Glycosaminoglycans/administration & dosage,adverse effects,therapeutic use · Hip Dysplasia, Canine/drug therapy · Injections, Intramuscular/veterinary · Lameness, Animal/etiology · Male · Pain Measurement/veterinary · Range of Motion, Articular
Fujiki 2007 (context only, uncontrolled): lameness improved in 12 of 16 osteoarthritic dogs after PSGAG — with no control group, this cannot show the drug caused it
Controlled clinical trial — uncontrolled treatment series in osteoarthritis (record's publication type; no placebo or comparator group)
Who: Dogs: 16 dogs with osteoarthritis (chronic lameness history, osteophytes on radiographic evaluation of the affected joint) and 5 clinically normal dogs, in a clinical/research setting; PSGAG was administered intramuscularly twice a week for a total of 8 treatments to all dogs with osteoarthritis and to the clinically normal control dogs.
Result: Lameness scores after PSGAG treatment in osteoarthritic dogs improved in 12 of the 16 dogs, and lameness scores decreased significantly after treatment compared with before treatment. Serum cartilage oligomeric matrix protein (COMP) concentrations in osteoarthritic dogs were significantly higher than in control dogs before treatment; in the 9 dogs with hind limb lameness whose scores improved significantly, serum COMP concentrations correspondingly decreased, while after treatment the 7 dogs with forelimb lameness kept significantly higher lameness scores and COMP concentrations than the hind-limb dogs. The authors concluded that intramuscular PSGAG inhibited COMP degradation in dogs with osteoarthritis and that decreases in serum COMP might be related to improvement in lameness.
Watch out: CONTEXT ONLY — this record is uncontrolled: every osteoarthritic dog received PSGAG, there was no placebo or untreated osteoarthritic comparison group, and the record does not state randomisation or blinding, so neither is claimed. A significant before-and-after change in an uncontrolled series is not evidence against placebo — regression to the mean, natural fluctuation and observer expectation all predict the same pattern. It is carded only to show what the osteoarthritis-specific literature actually consists of, and to keep its biomarker findings (COMP, MMP activities) from being mistaken for a clinical efficacy trial.
Fujiki M, Shineha J, Yamanokuchi K, Misumi K, Sakamoto H. Effects of treatment with polysulfated glycosaminoglycan on serum cartilage oligomeric matrix protein and C-reactive protein concentrations, serum matrix metalloproteinase-2 and -9 activities, and lameness in dogs with osteoarthritis. Am J Vet Res. 2007;68(8):827-33. PMID: 17669022. Registry ID: none in the record. MeSH: Animals · Anti-Inflammatory Agents, Non-Steroidal/therapeutic use · C-Reactive Protein/metabolism · Dog Diseases/drug therapy · Dogs · Extracellular Matrix Proteins/blood · Glycoproteins/blood · Glycosaminoglycans/therapeutic use · Lameness, Animal/drug therapy · Matrilin Proteins · Matrix Metalloproteinase 2/blood,metabolism · Matrix Metalloproteinase 9/blood,metabolism · Osteoarthritis/drug therapy,veterinary
Synthesis: the one placebo-controlled trial was null, and the one osteoarthritis series had no controls — benefit is unproven, not disproven in every joint
Synthesis
Who: Synthesis of the cards above: de Haan 1994 (84 evaluable dogs with hip dysplasia, double-blinded, randomised, placebo-controlled, four arms) and Fujiki 2007 (16 dogs with osteoarthritis, uncontrolled, context only).
Result: Read together: (1) against placebo, intramuscular PSGAG has never shown a statistically significant clinical benefit in dogs — the single controlled trial's between-group differences were not significant at any of the three doses; (2) the osteoarthritis-specific literature adds only an uncontrolled series and in-vitro/explant work, neither of which can carry a clinical claim; (3) tolerability in the controlled trial was clean (no local or systemic adverse reactions related to the drug observed). The fair summary for practice is that PSGAG's clinical efficacy in canine osteoarthritis rests on habit and uncontrolled observation, not on controlled evidence — while the null trial's four-way split means a small benefit, especially at 4.4 mg/kg, has not been excluded either.
Watch out: Do not upgrade this shelf on the Fujiki before-and-after result, on explant or cell-culture PSGAG studies (not carded — VetMed does not accept in-vitro work for clinical claims), or on pentosan polysulfate trials: pentosan is a related but different product with its own evidence base. A modern, adequately powered, placebo-controlled trial in osteoarthritic dogs would change this shelf; none was found.
Synthesis of de Haan JJ et al. PMID: 8066981; Fujiki M et al. PMID: 17669022. Registry IDs as on the individual cards.
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