iv been researching for the better part of 2 days on comfortis.
i have a major infestation and everthing i try on my samoyed and husky just doesnt work.
i have read many posts even to the point of dogs dying from twisted stomaches and constant vomiting (majority in boxers, iv read they have very sensitive stomaches)
majority of what iv read is all positive, but adverse reactions have been noted.
posts from comfortis in the US
http://www.examiner.com/x-14505-Atlanta-Pe...d-death-in-dogs
comfortis website
https://www.elancopet.com.au/products/comfortis.cfm
i am still a little reluctant to try is as it hasnt fully been confirmed for use in males and females in regards to fertility and breeding, also am scared of any adverse reactions that could occur when im not home.
by far the cheapest is on ebay $20 less than the vets
hope this info helps