Veterinarians know urinary incontinence or involuntary urine leakage is a common problem encountered in dogs. You may notice incontinence occurring at routine times, including when your dog is sleeping, or at less predictable times up to several times per day.
You should be aware of several potential causes to this problem. Questions regarding the timing and age of onset of the incontinence will help your pet’s veterinarian determine if the condition may have existed prior to or shortly after birth, shortly after being spayed, or if another reason is causing the incontinence. A thorough physical evaluation by the veterinarian may be necessary to determine proper treatment.
Urine leakage in spayed, older female dogs may commonly be attributed to urethral sphincter incontinence. This condition will usually start months to years after being spayed. The goal of drug treatment is to increase the urethral tone and continence. Estrogens and alpha-adrenergic agonists are the two drug classes identified to help increase urethral sphincter tone.
The alpha-adrenergic agonist, phenylpropanolamine, also known as PPA (Proin, Propalin), is a commonly prescribed treatment option for urethral incontinence. Side effects of phenylpropanolamine may include restlessness, irritability, panting, excitability and increased blood pressure. Phenylpropanolamine should not be used in dogs with pre-existing high blood pressure. Phenylpropanolamine may be prescribed alone or in combination with estrogen therapy. The combination treatment is believed to provide a synergistic effect, meaning the combination may be more effective than either drug alone.
Estrogen therapy may also be considered for dogs who do not tolerate phenylpropanolamine. Many veterinarians are familiar with the estrogen product called diethylstilbestrol, also referred to as DES. Diethylstilbestrol is no longer made by a drug manufacturer and must be obtained through a compounding pharmacy like VetRxDirect. Diethylstilbestrol usually starts with a loading phase including five to seven days of daily treatment. In most cases, one to two doses per week are given thereafter.
A new FDA approved, veterinary-labeled, estrogen treatment option named Incurin (estriol) has recently been introduced. Incurin is made by Merck Animal Health and is available in a 1 mg estriol (sometimes referred to as oestriol) tablet. Incurin is indicated for the treatment of urinary incontinence due to sphincter mechanism incontinence (SMI) in spayed female dogs. Treatment is recommended to be started at one tablet per day for 7 to 14 days. If treatment is effective, your veterinarian may reduce this to the lowest effective dose. Always consult with your veterinarian before adjusting any medications’ dosing or frequency.
Incurin is not for use in male dogs and should not be used during pregnancy or lactation. Possible side effects have included signs of estrus (in heat), swollen vulva/teats and nausea. Rare side effects may include vaginal bleeding and hair loss. You should consult your veterinarian if you notice any side effects and keep all follow-up appointments.
If you have any questions regarding your pet’s incontinence, contact your veterinarian to schedule an appointment. If you or your pet’s veterinarian have questions about either of the drugs reviewed in this post, give us call. We here to answer any questions you have.
Shawn Roe, PharmD