I have a dog, so getting Interceptor was easy when I lived in BC. Since heartworm was in the area I lived I just got the Interceptor "for my dog", which was true anyway since I didn't have to use all the pills for ny dog.
I don't have a vet out here in Saskatchewan yet though.
Send some PMs to vendors and ask, I'm sure you can find some. Just remember to be discreet because you are essentially asking for a prescription drug by illegal means.