Pentosan Polysulfate Sodium

By Krista Williams, BSc, DVM, CCRP

What is pentosan polysulfate sodium?

Pentosan polysulfate sodium (Cartrophen®) is a disease-modifying osteoarthritis drug (DMOAD) used to treat non-infectious and traumatic arthritis in dogs.

Pentosan polysulfate sodium (PPS) is also used “off-label” in cats. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully, as their directions may be significantly different from those on the label.

How is pentosan polysulfate sodium administered?

PPS is given as subcutaneous (under the skin) injections every five to seven days for up to four doses. This series of four injections may be repeated up to a total of three 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 advise where to dispose of the sharps container.

It can take up to four weeks to see the medication’s beneficial effects.

Are there any potential side effects from pentosan polysulphate sodium?

Side effects from PPS are rare in dogs and cats, provided it is given according to label recommendations and at the prescribed interval (or for off-label use, according to the directions given by your veterinarian). Side effects can include transient pain at the injection site, short-lived vomiting or diarrhea, and abnormal bleeding.

If you observe any abnormal signs, such as appetite loss, lethargy, bruising, continued vomiting and/or diarrhea, blood in vomit or stool, or black and tarry stools, contact your veterinarian. At that time, make sure your veterinarian is aware of any other medications or natural remedies that you are giving to your pet.

Are there any risk factors for this medication?

PPS should not be used in pets with a known hypersensitivity to it, in pets with known or suspected bleeding disorders or immune-mediated arthritis, or in pets with severe kidney or liver disorders.

Safe use of PPS has not been established in breeding, pregnant, or lactating dogs or cats. Your veterinarian will advise you on the safety of PPS use in your pet.

Are there any drug interactions that I should be aware of?

There are no known definitive contraindications; however, this medication should be used with caution with anticoagulants and anti-platelet medications, as it may increase the risk of abnormal bleeding. It should be used with caution with glucocorticoid steroids and nonsteroidal anti-inflammatory drugs (NSAIDs), as they can mask the signs of joint infection and increase the risk of bleeding.

Is there any monitoring that needs to be done with this medication?

There is no specific monitoring required for pets receiving PPS beyond watching for improvement of clinical signs of arthritis.

How do I store pentosan polysulfate sodium?

Store PPS in the original vial and in the box at room temperature below 25°C (77°F), protected from light. 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.

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