As it turns out Revolution sells a product that can be used on both puppies and kittens - same active ingredients. That, to me, says that it's safe to use on both as long as you pay attention to the dosage.
See this site...
I found a site that sells Stronghold and came across the following information. Pay special attention to the last sentance in the disclaimer. It seems that the only reason it's not sold in the US is because of packaging regulations. I though it was interesting:
Here's the website where I found...
