FDA Approves Incontinence Drug for Female Spayed Dogs

Spaying female dogs greatly reduces the pet overpopulation problem but 20% of spayed dogs will become incontinent sometime after their operation due to estrogen-responsive urinary incontinence, according to the ASPCA. Now a new prescription drug, Incurin (estriol), specifically for dogs was approved in July, 2011 to treat estrogen-responsive urinary incontinence. Incurin, made by Merck Animal Health in New Jersey, will be available to American vets later in 2011.

In some countries like Australia, the UK and Ireland, estriol has been used for women. Please do not give human estriol to dogs.

My Dog's Incontinence

My mongrel dog Pony became incontinent about one year after her spaying. Will I be asking my vet about Incurin? No, because Pony happens to do very well on her current medication, a hormone called diethylstilbestrol (DES). In fact, she's done so well that her last accident was over a year ago. But if she stops responding to DES, then I will look into Incurin.

Estrogen-responsive urinary incontinence is not to be confused with submissive urination. Puppies of both sexes and young dogs will dribble a few drops of urine as an appeasement gesture done when the pup is very scared or very excited. A dog with estrogen-responsive urinary incontinence urinates in great puddles and not just a few drops.

Why Did Pony Become Incontinent?

Some spayed female dogs may lack the ability to hold onto their urine when they are sleeping. This is because estrogen helps the bladder to retain muscle tone. Once a dog becomes spayed, she loses her natural estrogen supply. Pony would have accidents in her sleep but not when awake.

Spayed dogs most prone to developing estrogen-responsive urinary incontinence are overweight or any dog weighing over 20 kilograms or just over 44 pounds. Pony's healthy weight is about 60 pounds, but she often is a few pounds more. Smaller female dogs and those that maintain a healthy weight are less likely to become incontinent, points out "The relationship of urinary incontinence to early spaying in bitches"; S. Arnold, et al.; Journal of Reproduction and Fertility; 2001.

Side Effects

Incurin can cause side effects in dogs, including vomiting, noticeable swelling of the vulva, loss of appetite and polydipsia or drinking more water than usual. A dog may get one or all of these side effects. Polydipsia is also a symptom of diabetes, so do not ignore these symptoms. Contact your vet as soon as possible about any side effects that you think are weird.

Resources

ASPCA Virtual Pet Behaviorist. "How Will Spaying Change My Dog?" http://www.aspcabehavior.org/articles/46/How-Will-Spaying-Change-My-Dog.aspx

DVM360. "FDA approves first veterinary drug to treat urinary incontinence in female dogs." August 2, 2011. http://veterinarynews.dvm360.com/dvm/Breaking+News/FDA-approves-first-veterinary-drug-to-treat-urinar/ArticleStandard/Article/detail/733840

Drugs.com. "Incurin." http://www.drugs.com/international/incurin.html

Author's personal experience