April 1, 2019

The U.S. Food and Drug Administration announced today the approval of PROIN ER (phenylpropanolamine hydrochloride extended-release) tablets for the control of urinary incontinence due to urethral sphincter hypotonus in dogs.

Urinary incontinence occurs when a dog loses its ability to control when it urinates. Urinary incontinence can occur as dogs age and as the dog’s muscle in its urethra (the body part that leads from the dog’s bladder to outside its body) weakens and loses control over its ability to hold back urine. This condition is called urethral sphincter hypotonus.

PROIN Chewable Tablets are already approved for use in dogs for twice-a-day administration. This approval of once-a-day extended-release formulation of PROIN ER will offer veterinarians and pet owners an alternative option to the currently approved PROIN Chewable Tablets that are administered twice a day.

The effectiveness of PROIN ER was demonstrated in a clinical field study involving 119 client-owned dogs. The study enrolled dogs previously diagnosed with urinary incontinence due to urethral sphincter hypotonus who were administered the twice-a-day PROIN Chewable Tablets and considered controlled for their incontinence.

For one week, the owners recorded the number of urinary “accidents” per day and whether the dog received the PROIN Chewable Tablet doses. Dogs were then transitioned to once-a-day dosing of PROIN ER. For the first 28 days that the dogs were given PROIN ER, the owners recorded how many urinary accidents occurred each day. The number of urinary accidents during the fourth week of PROIN ER administration was compared to the one week of PROIN Chewable Tablet administration. Seventy-five of the 104 dogs who completed the study had zero accidents the first week on the twice-a-day PROIN tablets and also had zero accidents during the fourth week after they were transitioned to once-a-day PROIN ER. Nineteen dogs had fewer incidents of urinary incontinence on the once-a-day PROIN ER than when they were given the twice-a-day PROIN formulation, and 10 dogs had more incidents of urinary incontinence on the once-a-day PROIN ER than on the twice-a-day PROIN formulation. The dogs continued to receive PROIN ER and monitoring for adverse reactions for a total of 180 days.

The most common adverse reactions seen in dogs who were administered PROIN ER were vomiting, body weight loss, hypertension and diarrhea. Vomiting and/or diarrhea that occurred within the first week after starting PROIN ER typically resolved, while other dogs had intermittent vomiting or diarrhea during the course of the study. Dogs that experienced body weight loss or hypertension generally experienced these reactions throughout the study.

PROIN ER will be available by prescription only because a licensed veterinarian is needed to diagnose the cause of urinary incontinence and to determine whether PROIN ER is an appropriate treatment. PROIN ER should not be used in dogs weighing less than 10 pounds.

PROIN ER is available in 18, 38, 74, or 145 mg tablets and is manufactured by Pegasus Laboratories, Inc. of Pensacola, Florida.

For more information:

• FOI summary