We just started using the Nexgard for flea and tick, it's a chewable much like Heartgard. Maggie hated the Frontline, she would also get lethargic and act sickly. I split the vial between her and Buster but she still acted lethargic and sickly, however, I never saw her vomit. We use the Heartgard and have used it with success.
__________________ Jeanie, mom to Buster and Maggie  |