i give Kaydee what the vet recommended (heart guardplus) but i have known some people that give the horse wormer Ivermec to their dogs instead of the heart guard.... when i asked the vet he kinda rolled his eyes and gave an answer kind of like "hmm yeah well... its ok BUT... this is better"...

[quote user="ColleenC"]Actually, hearworm meds don't stay in the system. [/quote] ColleenC is correct. Interceptor and Heartgard are out of the dog's system in 24-48 hours. The "preventatives" prevent adult heartworms by killing immature heartworms. Heartworm "treatments"...