In humans doses of 60mg are used for depression but in doses of 10mg (for adults) it is used for migraines etc (I used to take it for that) so I guess it could help with bladder probs , but I think something like a low dose of diazepam would work better (from personal experience with migraines). Not heard of it used in animals but a lot of human drugs get used in animals in smaller doses.
Hope this helps