Proin for Dogs: Uses and Side Effects

Molly Price, DVM
By Molly Price, DVM. Medically reviewed by

Carina Fung, PharmD, MBA, BCPPS

Published Apr. 17, 2026
Proin for dogs, dog laying

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In This Article

Overview

PetMD’s medications content is written and reviewed by veterinary professionals to answer common questions about how medications work, their side effects, and what species they are prescribed for. This content should not replace advice from your veterinarian. 

Key Takeaways

  • Proin (active ingredient phenylpropanolamine) is used to treat urinary incontinence in dogs, especially spayed females with urethral sphincter mechanism incompetence (USMI).
  • Proin is FDA-approved for use in dogs.
  • ​​Proin ​works by stimulating certain receptors, which increase urethral muscle tone and improve bladder control.
  • Proin is given by mouth once or twice daily as directed by a veterinarian.
  • Dogs with high blood pressure, heart disease, liver disease, kidney disease, diabetes, or glaucoma should use Proin cautiously under veterinary supervision.

What Is ​​Proin Used for in Dogs?

​​Proin​ (phenylpropanalamine) is a veterinary prescription medication FDA​-​approved for the control of urinary incontinence in dogs ​that is caused by​ urinary sphincter hypotonus​.​ ​This​ condition ​occurs ​​when ​the muscles​ that​ control​ ​​urine​ flow ​from​the bladder are ​weakened​, ​leading to​ urine ​leakage, often while ​​a​ dog is resting or sleeping. 

Proin is available in two formulations: 

  • ​​Proin​, a flavored chewable tablet given twice daily 

  • ​​Proin ER​, an extended-release flavored chewable tablet given once daily 

Proin is not effective ​for ​dogs ​whose ​urinary incontinence ​is caused by neurologic disease or malformations. 

​​​Is Proin FDA-Approved for Dogs? 

​​Yes, Proin ER is FDA-approved​ for ​use in ​dogs ​to help control ​urinary incontinence ​​caused by​ urinary sphincter hypotonus.  

Speak with your veterinarian about whether Proin is right for your dog. 

​​​Proin ​​Considerations for Dogs

​​Proin should be used with caution in dogs with​:​ ​​​ 

  • ​​​Diabetes​     ​​​​ 

  • ​​​Glaucoma​     ​​ 

Proin ER should not be used in dogs weighing less than 10 pounds​, as safe dosing cannot be achieved.​​     ​ 

​​The safety of ​Proin has not been ​established in​ breeding, pregnant, or nursing dogs​.​ 

​​Use of ​Proin with certain medications ​may increase the risk of adverse effects. Your veterinarian can review your dog’s current ​medications, including vitamins and supplements, ​as well as any underlying ​medical conditions ​before prescribing Proin.​ 

How Does Proin Work in Dogs?

Proin is classified as a sympathomimetic amine medication​, which means it helps tighten certain muscles in the urinary tract​. ​It ​works by stimulating the receptors in the urethra, bladder, and urinary sphincter to ​improve muscle tone, helping your dog hold urine more effectively and reduce leaking.​​ 

How Do You Give Proin to Dogs?

Follow the directions on the drug label or as provided by your veterinarian. 

  • Proin is a flavored chewable tablet given twice daily. The tablet is scored, meaning it can be split safely into equal halves. 

  • Proin ER is ​usually​ given once daily​. Do not ​split or crush​ the tablets, as this can affect how the medication is released in the body​. 

  • Dogs weighing less than 10 pounds ​should not receive ​Proin ​E​R​, as a safe dose cannot be accurately given. ​​     ​ 

  • Proin can be given with or without food​. ​Proin ER should be given with food. 

  • ​​Make sure your dog has access to fresh​ water ​at all ti​​m​​e​​s​​, as this medication may increase thirst. 

  • Dogs may ​be switched ​from Proin to Proin ER without a break in ​treatment, but these medications should not be alternated​. ​T​he effectiveness and safety of ​​switching back and forth ​​have​ not been evaluated.   

​​​What Happens If You Miss a Dose of Proin? 

Speak with your veterinarian about what to do if a dose of Proin is missed.  

Generally, your vet may instruct you to give it when you remember, or if it is almost time for your dog’s next dose, to skip the missed dose and resume your normal dosing schedule. 

Do not give extra or double doses. 

What Are the ​​Side Effects of Proin in Dogs?

  • Weakness 

  • Urine holding 

If you believe your dog is experiencing any side effects, consult your veterinarian. 

Human Side Effects 

Proin is a prescription veterinary medication not intended for use in humans. 

​​​Humans should never take medication prescribed for pets, and pets should not be given medication prescribed for humans. Dosages often differ significantly. 

If you accidentally ingest a pet medication, seek medical attention or call ​Poison Control​ at 800-222-1222

Monitoring Your Pet 

​​​Specific monitoring or routine testing while your dog is on this medication may be recommended depending on your dog’s individual needs, other medications they may be on, and the issue that initially caused your dog to be placed on this medication.  

​​​When Should You Call Your Veterinarian? 

Call your veterinarian if you see any of the following, or if you have additional questions or concerns about the use of Proin: 

  • Severe side effects occur  

  • Your dog’s condition worsens or does not improve  

  • You suspect an overdose 

What Happens If a ​Dog ​Overdoses on Proin?

​​Overdoses of Proin given over an extended period can cause​:​ ​​​ 

  • ​​​H​igh blood pressure​​​ 

  • ​​​C​hanges in heart rate​​​ 

  • ​​​A​bnormal heart rhythm​​​ 

  • ​​​W​eight loss​​​ 

  • ​​​V​omiting​​​ 

  • ​​​D​iarrhe​a​​ 

  • ​​​D​ehydration​     ​​ 

  • ​​​E​levated liver levels​     ​​ 

If you suspect an overdose, seek emergency veterinary care or contact an animal poison control center. Consultation fees may apply. 

How Should Proin Be Stored for Dogs?

Keep the following storage tips in mind for this medication: 

  • ​​Store ​Proin ​at room​ temperature​, ideally​ between 68​–​77 F (20​–​25 C)​.​ ​B​rief exposure to temperatures between 59​–​104 F (15​–​40 C) ​is ​acceptable. 

  • Keep tablets in their original container until ready to use​, and p​rotect from moisture and light. 

  • ​​Store Proin out of reach of pets and children. Dogs may chew through bottles and accidentally ingest multiple tablets, which can lead to overdose. ​​     ​ 

  • ​​Always ​check the prescription label for specific storage instructions​.​​​​​ 

Proin for Dogs FAQs

How long does Proin take to work in dogs?

It may take several days of treatment with Proin before your dog’s urinary incontinence improves. In a ​six​​​​-month field study​, ​just over ​98% of owners reported satisfaction with Proin controlling ​their dog’s ​urinary incontinence. 

Is Proin safe for long-term use in dogs?

Yes, Proin is generally considered safe for long-term use in dogs ​when prescribed and monitored by a​ veterinarian. ​Your vet will determine whether ongoing use is appropriate based on your dog’s health and response to treatment.​​     ​ 

Can Proin cause high blood pressure in dogs?

Yes, Proin can cause high blood pressure in dogs​. Because of this, ​it should be used with caution in dogs with high blood pressure, heart disease, liver disease, kidney disease, diabetes, or glaucoma. 

Is Proin the same as phenylpropanolamine?

No​.​ ​P​henylpropanolamine is the active ingredient in Proin, but Proin is ​a brand-name veterinary medication approved for use in dogs to ​control urinary incontinence. ​P​henylpropanolamine ​products for human use have ​been ​​​withdrawn from the market​ at the time of this publication. 


Molly Price, DVM

WRITTEN BY

Molly Price, DVM

Veterinarian

Dr. Molly Price has practiced small animal medicine for over 20 years and is a graduate of Texas A&M College of Veterinary Medicine...


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