By Rania Gollakner, BS, DVM, MPH

What is phenylpropanolamine?

Phenylpropanolamine (brand names: Proin®, Propalin®, Cystolamine®, Uricon®, Uriflex-PT®) is a sympathomimetic medication used to treat urinary incontinence due to poor muscle tone in the urethral sphincter.

Its use in cats and dogs at certain doses to treat urinary incontinence 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 phenylpropanolamine given?

Phenylpropanolamine is given by mouth in the form of a tablet or liquid. It may be given with or without food; however, if vomiting occurs when dosed on an empty stomach, give future doses with food. Measure liquid forms carefully. Provide access to fresh water at all times. If incontinence occurs at night, give the largest dose at night, before going to sleep.

This medication will take effect quickly, in about 1 to 2 hours, and improvement 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, increased thirst, restlessness, irritability, and difficulty urinating. Serious side effects include seizures, collapse, or stroke-like signs (for example, not being able to walk).

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?

Phenylpropanolamine should not be used in pets than are allergic to it or in pregnant pets. It should be used cautiously in pets with glaucoma, seizures, enlarged prostate, elevated thyroid hormone, diabetes mellitus, heart or vessel disorders, kidney disease, or high blood pressure. Use phenylpropanolamine cautiously in nursing pets, as safety has not been studied.

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with phenylpropanolamine: aspirin, isoflurane/desflurane/sevolurane, monoamine oxidase inhibitors (MAOIs), nonsteroidal anti-inflammatory drugs (NSAIDs), reserpine, other sympathomimetics, or tricyclic antidepressants.

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?

Your veterinarian may monitor your pet to be sure that the medication is working. Monitor your pet at home for serious side effects. Blood pressure should be monitored regularly: frequently when your pet first starts taking phenylpropanolamine, and then at least twice per year.

How do I store phenylpropanolamine?

Store this medication at room temperature, and protect from light and moisture.

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.

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