That's funny that this same question came up!! I was driving to work last week, when on the local morning radio station I listen too was talking about the co-hosts dog eating the whole package of heartworm pills (6 month supply). They called the local vet on the air and the vet said that there is no problem with taking more than one, it just doesn't protect any longer or anything. The vet said your dog could eat 100 and it would not harm them!!
Just to be sure for yourself, you could call your local vet, but hope this helps you out!!!
-Ashley & Emmy
