Pentosan Polysulfate Sodium (PPS) For Cats

Key points

  • What is pentosan?  Pentosan is a prescription medication used to treat osteoarthritis and cystitis in cats
  • Drug name: Pentosan polysulfate sodium
  • Brand names: Zydax, Cartrophen-Vet, Elmiron, Pentosan, Sylvet
  • Properties: Anti-inflammatory, osteoarthritis disease-modifier (DMOAD)
  • Available as: Injection, capsule
  • Caution:  Cats with coagulopathies, kidney and liver disease
  • Administered: Injection, capsule

What is pentosan?

Pentosan polysulfate sodium (PPS) is a semi-synthetic polysaccharide ester derived from beechwood hemicellulose used for the treatment of osteoarthritis and idiopathic cystitis. It is derived from the European beech tree and is regarded as semi-synthetic pharmaceutical because it is derived from a naturally occurring starting material.

Pentosan polysulfate sodium has not been approved by the FDA for use in cats in the United States, but many veterinarians prescribe it as an extra-label therapy to treat arthritis disease progression as well as provide relief from symptoms. Osteoarthritis (OA) is a painful condition that occurs when the protective cartilage that cushions the ends of your bones wears down over time.

Arthritis statistics:

  • 20% of cats over 1 have some signs of arthritis
  • 60% of cats over 6 have arthritis
  • 90% of cats over 12 have arthritis

Osteoarthritis symptoms:

  • Grooming less
  • Unkempt appearance
  • Reluctance to jump
  • Soiling outside the litter tray
  • Loss of appetite
  • Pain when touched
  • Limping

Mechanism of action

Pentosan polysulfate sodium has disease-modifying effects similar to polysulfated glycosaminoglycans (Adequan) and acts in several ways. The specific mode of action is not known, but it is thought to is said to have chondroprotection and chondrostimulation properties.

  • Stimulates chondrocytes (cartilage producing cells) to produce healthy glycosaminoglycans (GAGs) for cartilage health and joint fluid production
  • Inhibits proteolytic enzymes which can degrade proteoglycans (water-absorbent molecules that create a cushion to absorb pressure), thereby preventing or reducing connective tissue flexibility and resistance to compression.
  • Mild anticoagulant (1/15th the anticoagulant strength of heparin) and fibrinolytic properties could improve blood flow and nutrition to the joint structures
  • Adheres to the bladder wall mucosal membrane and acts as a buffer to prevent irritating solutes in the urine of cats with interstitial cystitis


3 mg per kilo subcutaneous (under the skin) or intramuscular once a week for four weeks and then as a booster as needed.

This will provide 3-6 months of relief from arthritis.

An oral capsule is also available under the brand name Sylvet for home administration for cats who need more regular treatment.

How long does it take pentosan polysulfate sodium to work?

There is usually an improvement in symptoms after 2-3 injections.


There is no information regarding overdose although potentially it could cause bleeding, thrombocytopenia, liver function abnormalities and GI distress. [1]

Drug interactions

No specific drug interactions have been found although care must be taken in cats who are on drugs that affect coagulation such as NSAIDs, aspirin, heparin.


Evaluate cats who have hemophilia and thrombocytopenia (low blood platelets).

It may be necessary to stop treatment before a scheduled surgery.


Do not use in cats with a known hypersensitivity to the drug.

Contraindicated in the treatment of septic arthritis.

The UK injectable product (Cartrophen-Vet) licensed for use in dogs lists the following:

Do not use in dogs with advanced liver or kidney impairment, evidence of infection, blood disorders, coagulation disorders, bleeding or malignancy (especially hemangiosarcoma). [2]

Not recommended for use in pregnant animals as safety has not been studied.

Do not administer at the time of parturition (birth) due to its anticoagulant effects.

Other treatment options

Pentosan polysulfate sodium may be used as a stand-alone treatment, or in conjunction with other therapies which include:

Weight management: Control the weight to reduce excess pressure on the joints.

Prescription diet: Hill’s j/d contains high levels of omega-3 fatty acids, glucosamine and chondroitin to reduce inflammation in arthritic joints and help slow down progression.

Neutraceuticals: Foods or food compounds that have a medical benefit.

  • Glucosamine – Glucosamine is a sugar produced by the body and a building block of cartilage. Glucosamine supplements can help to slow the breakdown of cartilage and help damaged cartilage to heal.
  • Chondroitin sulfate – A naturally occurring molecule and vital part of cartilage that may stop cartilage degrading along with drawing water to the joint.
  • Omega 3 fatty acids – Natural anti-inflammatory supplements which can be added to food.


[1] Plumb’s Veterinary Drug Handbook 9th Edition (Page 1283) – Donald C. Plumb

[2] Plumb’s Veterinary Drug Handbook 9th Edition (Page 1283) – Donald C. Plumb


  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio

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