By Rania Gollakner, BS, DVM, MPH

What is pentoxifylline?

Pentoxifylline (brand names: Trental®, PTX) is an immunomodulatory agent used to treat certain immune-mediated skin conditions and inflammation of the blood vessels, leading to poor blood flow. This includes, but is not limited to, ear margin dermatitis and cutaneous lupus in dogs, and navicular disease in horses.

Its use in cats, dogs, and horses to treat skin and vessel disease is ‘off label’ or ‘extra label’. 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 pentoxifylline given?

Pentoxifylline is given by mouth in the form of a tablet. It may also be specially compounded into a liquid form. Give with food. Measure liquid forms carefully.

This medication should take effect within 1 to 2 days, and improvements in clinical signs should follow.

What if I miss giving my pet the medication?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

The most common side effects include vomiting, diarrhea, lack of appetite, excitement, or restlessness. Serious side effects include seizures, collapse, fever, or severe skin rashes.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Pentoxifylline should not be used in pets that are allergic to it or allergic to xanthines. Do not use in pets with bleeding in the brain or the eye. Use cautiously in pets with severe liver or kidney disease or those at risk for bleeding. Use pentoxifylline with extreme caution in pets that are pregnant or nursing.

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with pentoxifylline: antihypertensive drugs, cimetidine, insulin, nonsteroidal anti-inflammatory drugs (NSAIDs), platelet-aggregation inhibitors, theophylline, or warfarin.

Pentoxifylline may also interact with skin allergy testing; discontinue this medication at least one week prior to allergy testing.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

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

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working. Monitor your pet at home for serious side effects, including signs of bleeding. If bleeding is suspected, your veterinarian may monitor blood cell counts.

How do I store pentoxifylline?

Store the tablets at room temperature between 68°F and 77°F (20°C and 25°C ), protected from light.

What should I do in case of 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.

Related Articles