Pentoxifylline

Major Uses

Pentoxifylline is a hemorheologic agent and methylxanthine drug that is beneficial in the treatment of atopic dermatitis and other skin conditions, endotoxic shock and other refractory forms of shock, and thrombosis. The drug increases red cell flexibility and decreases blood viscosity to improve blood flow. It also inhibits neutrophil adhesion and activation and increases leukocyte deformability.

Most commonly, pentoxifylline is used to treat disorders of microcirculation, or circulation in the smallest blood vessels. It improves blood flow, tissue viability, and tissue oxygenation. Pentoxifylline is not approved by the Food and Drug Administration for use in animals, but it is prescribed legally as an extra-label drug for that purpose. This medication is most commonly used in horses, but it may also be used in small animals.

Common Precautions

There is limited information available about the side effects of pentoxifylline in animals. The most common side effects appear to be diarrhea, loss of appetite, and nausea. Less common side effects can be severe and may include edema, vomiting, cardiac arrhythmias, hypotension, liver dysfunction, malaise, nasal congestion, dyspnea, intestinal gas or bloat, conjunctivitis, urticaria, pruritus, anxiety, and tremor.

It is important to monitor blood clotting time, liver enzymes, and arterial blood pressure during treatment with pentoxifylline. Pentoxifylline should not be given to animals that are intolerant to methylxanthenes. It is not for use in pregnant animals or in those with cerebral or retinal hemorrhage. Caution is needed when using in animals with severe kidney, liver, or bleeding problems. This drug passes into the milk of nursing mothers. Animals with existing seizure disorders should not be given pentoxifylline.

Pentoxifylline may interact with certain other supplements or medications, including warfarin and other anticoagulants, cimetidine, theophylline, hypertensive drugs, and quinolone antibiotics. Non-steroidal anti-inflammatory drugs may also interact with pentoxifylline, but studies are conflicting.

Pentoxifylline should not be used in animals with a known allergy or hypersensitivity to the drug. Overdose of pentoxifylline may cause seizures, flushing, GI distress, hypotension, heart rhythm changes, agitation, somnolence, unconsciousness, and fever. Any known or suspected overdose should be reported to a veterinarian right away.

Storage

Pentoxifylline should be stored in its original packaging, at room temperature, and out of the reach of children and animals. It should not be exposed to light.

Administration

Pentoxifylline is available as a 400 mg extended/controlled release tablet. The dose of pentoxifylline varies depending on the condition being treated and other factors. In dogs, the typical dose of Pentoxifylline is 5 to 12.5 mg/lb (10 to 25 mg/kg) every 12 to 24 hours. There is no established dose for pentoxifylline use in cats.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

If a dose of pentoxifylline is missed, it should be given as soon as possible. If it is almost time for the next dose, the missed dose should be skipped and the regular schedule resumed. Two doses of pentoxifylline should not be given at once.