What is pentosan polysulfate sodium?
Pentosan polysulfate sodium (brand name: Cartrophen®) is a disease modifying osteoarthritis drug (DMOAD) used to treat noninfectious and traumatic arthritis in dogs.
Pentosan polysulfate sodium (PPS) is also used off label (extra label) in cats. Many drugs are commonly prescribed for off-label use in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.
How is PPS administered?
- PPS is given as subcutaneous (under the skin) injections every 5 to 7 days for up to 4 doses. This series of 4 injections may be repeated up to a total of 3 times per year.
- Follow your veterinarian’s instructions on how to administer the injection.
- Measure the dose carefully to prevent overdose.
- Discard the needle and syringe after each dose, without re-capping the needle, in a dedicated sharps container. Your veterinarian will let you know where to dispose of the sharps container.
It can take up to 4 weeks to see the medication’s beneficial effects.
Are there any potential side effects from PPS?
PPS may rarely cause the following side effects:
- Transient pain at the injection site
- Short-lived vomiting or diarrhea
- Abnormal bleeding
Serious adverse reactions may occur. If any of the following signs develop, stop giving PPS and contact your veterinarian immediately:
- Appetite loss
- Lethargy
- Bruising
- Continued vomiting and/or diarrhea
- Blood in vomit or stool
- Black and tarry stools
Drug sensitivities can develop over time, with repeated exposure. Your pet may have no reaction after the first few doses but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment and notify your veterinarian if you have any concerns.
Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately.
Are there any risk factors for this medication?
DO NOT USE PPS in:
- Pets with a known hypersensitivity to it
- Pets with known or suspected bleeding disorders
- Pets with immune-mediated arthritis
- Pets with severe kidney or liver disorders
USE WITH CAUTION in:
- Pets that are breeding, pregnant, or lactating (safety has not been established)
Are there any drug interactions that I should be aware of?
Several medications should be used with caution when given with PPS, including:
- Anticoagulants and anti-platelet medications (may increase the risk of abnormal bleeding)
- Glucocorticoid steroids
- Nonsteroidal anti-inflammatory drugs (NSAIDs; they can mask the signs of joint infection and increase the risk of bleeding)
Be sure to tell your veterinarian about any medications (including vitamins, supplements, and herbal therapies) that your pet is taking before starting any treatment.
Is any monitoring needed with this medication?
- Monitor your pet closely for any changes, including improvements or side effects such as those noted above. Contact your veterinarian with any changes.
- Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.
How do I store PPS?
- Store PPS in the original vial and box at room temperature, below 25°C (77°F).
- Protect from light.
- Keep the container out of reach of children and pets. 
- This medication has a shelf life of three months after opening.
What should I do in case of an emergency?
If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet's weight and symptoms.
