Proin ER is a safe and effective FDA-approved once-a-day tablet that controls urinary incontinence in dogs due to urethral sphincter hypotonus. It works by increasing urethral sphincter tone to help prevent urinary accidents. It's easy to administer. The liver-flavored tablets are given with food in a single dose per day. The patented release technology provides controlled release that ensures steady absorption. Proin ER provides the same proven efficacy as Proin in extended-release tablets. Proin ER requires a prescription from your veterinarian.