Dog Medication for large breeds

I actually live in Dongguan but will come to HK tomorrow. I'm looking for dog medication for my dogs. They're both large breeds (OES and Golden Retriever) and I'm having a hard time getting their heartworm meds in China. Right now, they're on Revolution but I have to use 2 doses of the 20-40lbs for my OES. The Golden Retriever is still a puppy but when she gets to my OES' size, well, it will put a pretty big dent in my wallet.


I'm not sure if I can get meds like Revolution in HK, of whether or not i need a prescription like I do back in the states. In china, they're pretty much lax in regarding these meds and of course most things are for small dogs which I have to double up in almost everything i buy for them and i am concern about the effect it may have for them. So any suggestions on where to obtain heartworm meds, or dewormers will be highly appreciated

thanks. i'll go look for it today