[Barbara Winters]

Incontinence after neutering can occur but is relatively rare. The reason for the antihistamine is that these types of drugs help certain types of incontinence and your vet is most likely doing a medication trial before performing other more extensive and expensive tests.

Drug therapy is designed to increase the smooth muscle tone of the proximal urethra. The smooth muscle is under alpha adrenergic control, and to increase smooth muscle tone a drug trial with an alpha-receptor agonist should first be tried. Two drugs commonly used are phenylpropanolamine and ephedrine; phenylpropanolamine is preferred.From SPHINCTER-MECHANISM URINARY INCONTINENCE

Additional testing that is used to diagnose the cause of incontinence is described in detail in Workup of the Urinary Incontinent Dog by Richard Walshaw, BVMS

I'd certainly look at behavioral issues in addition to the medication trial. If this only occurs at night, go outside with him on leash and make sure he goes. Bring a flashlight so you can see that he really is peeing. Also you may want to start a housetraining refresher course to make sure this isn't a factor.

Good luck and please keep us posted.

[ October 07, 2003, 08:29 PM: Message edited by: Barbara Winters ]