Adequan for Cats: Polysulfated Glycosaminoglycan for Joints

What Adequan Is and Why Vets Use It in Cats

Adequan is the brand name for polysulfated glycosaminoglycan, often shortened to PSGAG. It is an injectable medication originally developed and FDA-approved for treating degenerative joint disease in dogs (and, in a different formulation, in horses). For Adequan cats, the medication is used off-label — meaning veterinarians prescribe it based on clinical experience and the broader body of evidence on PSGAG, even though there is no FDA-approved feline label.

Off-label use is common and legal in veterinary medicine, and Adequan has become an increasingly popular tool for cats with osteoarthritis. The reason is simple: feline arthritis is far more common than once recognized, the treatment options have historically been limited, and Adequan offers a different mechanism of action than the drugs that simply mask pain.

This guide walks through how Adequan works, when vets choose it for cats, what to expect during treatment, side effects to watch for, and how the drug fits into a broader plan for managing feline joint disease.

How PSGAG Works at the Joint Level

To understand what Adequan does, it helps to picture what happens in an arthritic joint. Healthy joints are lined with smooth cartilage that lets bones glide easily. Synovial fluid bathes the joint, providing lubrication and delivering nutrients to the cartilage (which has no direct blood supply of its own). In arthritis, this orderly system breaks down: cartilage becomes thinner and rougher, inflammatory enzymes destroy joint tissues, and the synovial fluid loses its lubricating quality.

PSGAG is structurally similar to the natural building blocks of cartilage. When injected, it has several proposed effects:

• Inhibits enzymes that degrade cartilage
• Encourages the synthesis of new cartilage components
• Improves the viscosity and quality of joint fluid
• Reduces inflammation in joint tissues

Rather than simply blunting pain, Adequan aims to support joint health at a structural level. This is what makes it interesting for cats, whose pain options have historically been more limited than dogs’ due to feline sensitivity to many NSAIDs and other pain medications.

Why Cats Need Better Joint Care Options

Studies and clinical experience over the past two decades have made clear that feline arthritis is dramatically underdiagnosed. Many older cats — and even some middle-aged cats — quietly live with joint discomfort that owners mistake for “just getting older” or “becoming less playful.” Cats are masters at hiding pain, and they rarely limp the way dogs do. Instead, they:

• Stop jumping to favorite high spots
• Hesitate before going up or down stairs
• Sleep more and play less
• Groom less, especially over the back and tail base
• Get grumpy when picked up or handled
• Avoid the litter box if it requires a high step

If you recognize any of these in your cat, talk to your vet. A targeted exam, sometimes including imaging or a trial of pain control, can confirm whether arthritis is at play. For more on the bigger picture, see our overview of cat arthritis.

When Vets Consider Adequan for Cats

Veterinarians may consider Adequan for cats with:

• Confirmed or strongly suspected osteoarthritis, particularly in early to moderate stages where there is still cartilage to protect
• Joint dysfunction following injury or surgery
• Multiple-joint discomfort where systemic anti-inflammatory therapy is desirable
• Cats who cannot tolerate other pain medications due to kidney disease, GI issues, or other comorbidities

Because Adequan addresses the joint biology rather than just the pain signal, it is often considered a “disease-modifying” approach and may be paired with pain-focused medications, joint supplements, environmental changes, and weight management. The combination tends to outperform any single intervention.

How Adequan Is Given to Cats

Adequan is given by injection, typically into the muscle (intramuscular) or sometimes under the skin (subcutaneous). For cats, the subcutaneous route is often preferred because it is generally easier and less uncomfortable. Your vet will choose the route, dose, and schedule based on your cat’s weight and condition.

A typical approach is an initial loading phase of injections given more frequently over several weeks, followed by a maintenance phase with longer intervals between injections. The exact schedule varies by patient and by veterinarian preference, and your vet will tailor it to your cat’s response.

Some vets teach owners to give Adequan injections at home, which can save trips to the clinic and keep the schedule consistent. If this is offered, your vet will demonstrate the technique and provide proper supplies. If you are not comfortable giving injections, in-clinic dosing is always a reasonable alternative.

What Results to Expect

Owners who see good responses to Adequan often describe their cats as “more like themselves.” Specific changes can include:

• Increased willingness to jump up to favorite spots
• More play, especially short bursts of activity
• Better grooming, particularly over the back and tail base
• Less hesitation on stairs or in and out of the litter box
• Improved mood and willingness to be handled
• Smoother movement and posture

Improvements typically appear gradually over the loading phase rather than overnight. Some cats respond beautifully, some show modest improvement, and some do not appear to benefit. If you do not see meaningful change after the loading phase, talk to your vet about whether to continue, adjust, or pivot to a different strategy.

Side Effects and Safety

Adequan is generally well tolerated in cats. Reported side effects are relatively uncommon and usually mild:

• Mild soreness or swelling at the injection site
• Transient lethargy after injection
• Occasional mild gastrointestinal upset
• Rarely, allergic-type reactions

Because Adequan has mild blood-thinning properties due to its structural similarity to heparin-like compounds, vets generally avoid using it in cats with bleeding disorders, those on anticoagulant medications, and those scheduled for surgery within the next several days. Tell your vet about any past or planned procedures and any conditions that affect bleeding or clotting.

Warning signs that should prompt a call to your vet include:

• Significant swelling or pain at the injection site
• Hives, facial swelling, or signs of an allergic reaction
• Persistent vomiting or diarrhea
• Lethargy that does not resolve within a day
• Unexpected bleeding or bruising
• Difficulty breathing

Cats Who May Need Extra Caution

Adequan is generally a low-risk medication, but vets often think carefully before using it in cats with:

• Bleeding disorders or platelet abnormalities
• Concurrent use of anticoagulants
• Active infections, particularly joint infections
• Significant kidney or liver disease (vets will weigh the case-by-case picture)
• Pregnancy or lactation
• Known hypersensitivity to PSGAG products

For cats with cat kidney disease, who often cannot tolerate NSAIDs, Adequan is sometimes especially appealing because it offers an option that does not stress the kidneys the way NSAIDs can. However, the decision is always individualized, and your vet will weigh the full picture.

Combining Adequan With Other Strategies

Adequan rarely works alone in a real-world treatment plan. Common companions include:

• Joint supplements: Glucosamine, chondroitin, and omega-3 fatty acids may complement PSGAG.
• Pain medications: Including feline-specific NSAIDs (when appropriate), gabapentin for chronic and neuropathic pain, and newer monoclonal antibody therapies for feline osteoarthritis.
• Weight management: Even modest weight loss can dramatically reduce joint stress.
• Environmental modifications: Ramps, stairs, low-sided litter boxes, soft heated bedding, and easy access to food, water, and resting spots.
• Physical rehabilitation and acupuncture: Increasingly available from veterinary specialists.

The combination of disease-modifying therapy (like Adequan), pain control, lifestyle changes, and environmental support can transform an aging arthritic cat’s quality of life.

What to Do If You Miss an Injection

If you miss a scheduled injection of Adequan, contact your vet’s office for guidance. The general approach is to give the missed dose as soon as possible and adjust the schedule from there, rather than doubling up. Consistency, especially during the loading phase, helps the medication achieve and maintain its therapeutic effect, but a single missed dose is rarely a crisis.

Long-Term Use and Monitoring

For cats who respond well, Adequan is often continued long-term as part of an ongoing maintenance plan. Your vet may recommend periodic recheck exams, occasional bloodwork (especially in older cats and those with comorbidities), and regular reassessment of pain and mobility. Owners are often the best source of information here — your daily observations of how your cat is moving, eating, grooming, and engaging will help your vet fine-tune the plan.

If your cat’s response seems to wane over time, do not increase the dose on your own. Talk to your vet — they may adjust the dose, change the interval, layer in another medication, or investigate whether something else is contributing to the discomfort.

Frequently Asked Questions

Can I get Adequan for my cat without a prescription?

No. Adequan is a prescription medication that must be prescribed by a licensed veterinarian. Use in cats is off-label, which means your vet is taking responsibility for prescribing it based on clinical judgment. Buying from non-veterinary sources is risky — you cannot verify the quality, sterility, or strength of the product.

How quickly will I see results?

Most cats who respond to Adequan show improvement gradually over the loading phase, typically several weeks. Some cats show changes earlier, others take longer. If you have not seen meaningful improvement by the end of the loading phase, talk to your vet about next steps.

What if I miss an injection?

Contact your vet for guidance. The usual approach is to give the missed injection as soon as you can and adjust the schedule from there. Do not double-dose to “catch up.” Consistency matters most during the loading phase.

What side effects should I watch for?

Most side effects are mild — temporary injection site soreness, transient lethargy, occasional GI upset. Call your vet for significant injection site swelling, allergic-type reactions, persistent vomiting or diarrhea, unexpected bleeding or bruising, or any difficulty breathing.

Can Adequan be used with other pain medications?

Yes, and this is often the best approach. Adequan addresses joint biology while pain-focused medications like gabapentin and feline-specific NSAIDs (when appropriate) address pain signaling. Your vet will design a plan that fits your cat. Tell your vet about every medication and supplement your cat is on so the full plan can be coordinated safely.

Is Adequan safe for cats with kidney disease?

Adequan does not stress the kidneys the way NSAIDs can, which makes it appealing for cats with kidney disease. The decision is still individualized, and your vet will weigh your cat’s specific situation. Adequan is sometimes a particularly useful option for cats whose pain management is constrained by kidney concerns.

The Bottom Line

Adequan offers a meaningful option for cats with osteoarthritis, especially those who cannot tolerate NSAIDs or who need a disease-modifying approach in addition to pain control. Used as part of a thoughtful, multimodal plan and monitored regularly, it can substantially improve comfort and quality of life in arthritic cats.

If you suspect your cat is dealing with joint pain, do not chalk it up to age. Talk to your vet about a workup and ask whether Adequan, alone or as part of a broader plan, might help your cat feel like themselves again. The earlier feline arthritis is recognized and managed, the more years of comfortable, engaged life you can give your cat.