No prescription required that I know of. Here's the store locator for Toronto: http://www.triumphpet.com/locator/re...&citysearch=Go
Is it the Hi-Tor Neo diet for cats that you're looking at (I see you have a kidney cat)? Any particular reason you want to feed specifically Hi-Tor? I'm just looking at the ingredients and there are better quality foods out there:
Sufficient Water For Processing, Meat By-Products, Chicken, Animal Liver, Beef, Poultry Fat, Ocean Fish, Rice Flour, .....
"Meat by-products" and "animal liver" are too ambiguous for my taste. They are more likely to include 4D livestock (dead, dying, diseased, disabled) and roadkill, and are not a quality muscle meat. "Ocean fish" is another one of those catch-all terms that consist of the leftover dregs of the fishing industry. Rice flour is just a thickner, totally unnecessary for an obligate carnivore.
Cat's with CRF should be fed quality muscle meat protein sources. Something like Wellness is considerably better.