Our vet told us to NEVER use Hartz anything on our furbabies...What we do is use Sevin dust outside on the lawn (apply a couple times a year) and Advantix on the babies. Our kitty babies are indoor only so we don't fret much. Our new furbaby (Half Giant Schnauzer and half German Shepherd) is on Advantix and Heartguard. We had him bathed, dipped and groomed at the vet's the other day.
I'm SOOOOO sorry to hear about your furbaby...amazing how the little 4 legged creatures can walk in and steal our hearts...((((((((((((((((((((hugs))))))))))))))))))))))))))
TB