There has been a great deal of conversation of late on some of the boxer lists regarding urinary incontinence. Many breeders don't encounter this problem because their dogs remain intact, but more breeders are beginning to spay or neuter their older dogs when they have no further plans for reproduction to avoid such problems as pyometra and prostatic infections/prostatitis. While their are several causes for incontinence, the most common one veterinarians see is in spayed or neutered animals that are middle-aged. The typical presentation is a history of leaking while sleeping or relaxed and normal voluntary urination when awake. It is most common in spayed females, but neutered males are occasionally affected. It is more common at a young age in the Doberman pinscher than in any other breed, but any breed can be affected.
It is important that a complete workup of the urinary tract be performed prior to beginning therapy for incontinence. This includes taking a thorough history of the dog regarding reproductive status (spayed/neutered/intact), age at neutering, age at onset of incontinence, previous medical problems (especially those involving the urinary tract), history of trauma, description of the problem (frequency of occurance, amount of urine passed, awareness of leakage by the dog, etc.) The physical exam should include palpation of the bladder both full and after voiding, evaluation of the nerves that supply the urogenital area, observation of urination and evaluation of residual urine in the bladder after voiding. The dog should have a urinalysis done and a culture and sensitivity if their is evidence of infection or if the urine specific gravity is less than 1.020 (dilute urine).
If the urine is dilute, blood samples should also be submitted to rule out kidney disease or other organic disease that causes dilute urine (Cushings, diabetes mellitus, hypercalcemia). If the urine is extremely dilute and kidney function and other blood values are normal, further tests for urine concentrating ability are needed.
If the urine is normally concentrated, treatment for incontinence can be started as soon as infection has been ruled out by urinalysis.
My first choice of drug therapy is phenylpropanolamine HCl. There are few to no side effects. (I have seen one dog, a Springer Spaniel, become restless on it.) I have treated many client's dogs successfully with no ill effects for up to 8 years. My own Doberman female took phenylpropanolamine from the age of 3 until she died at the age of 13. If a dog fails to respond to proper dosing (which is 1.1mg/kg three times daily or one half milligram/pound three times daily for those not metrically inclined) I will then add DES. I hesitate to add DES in young dogs. There are side effects that can be caused by estrogen supplements. These include apparent estrus (yes, even in spayed bitches), mammary tumor development, and bone marrow suppression. While these are uncommon, the last two are far more serious than restlessness. The accepted dose for DES in a boxer sized dog is 1mg/day for 3-5 days, then 1mg weekly for maintenance. Many dogs that take phenylpropanolamine can be medicated twice daily once the incontinence is controlled, but some will always require three times daily dosing.
by: Wendy Wallner, DVM