Identification

• Proin, also known as Phenylpropanolamine (PPA) is a prescription medication commonly prescribed to increase urethral muscle tone in dogs. It is currently not FDA approved for veterinary use but it is often legally prescribed as an extra label drug.
  
  

Function

• Proin works by increasing sphincter tone in the urethra, which makes urine less likely to leak out the bladder. This form of incontinence is often seen in elderly spayed dogs because they no longer produce sufficient estrogen, which is a hormone that keeps the urethral muscles in good shape.
  
  

Considerations

• Proin was once used in humans but it has been banned by the FDA since 1999 because a study found that women using Proin had higher chances of hemorrhagic strokes. Because veterinarians feel the risks of stroke in dogs are low, this is generally not a concern.
  
  

Side Effects

• Adverse side effects in dogs are uncommon, but they may include increased heart rate, high blood pressure, loss of appetite and restlessness.
  
  

Dosage

• Proin is generally available through compounding pharmacies. According to Petplace.com the typical dosage of Phenylpropanolamine consists of 12.5 to 50 mg three times daily, depending on the dog's weight.
  
  

Time Frame

• Proin will not work overnight. In order to work, it must be given as directed for several days before dogs will likely show signs of improvement.