What dosage of heartworm should i get for my dog?

The dosage comes in 26-50 or 51-100 lbs My dog weighs 50 pounds and I am confused as to which one to get. Will the 51-100 be too much for him or will 26-50 not be enough? I know its very important to get him on heartworm so please help me out!

It is my general rule to always go with the lower dose.The vet will probably tell you to go with the higher dose, because they have the motivation to always "be on the safe side". You MUST buy the stuff from the vet (or with a prescription), so you might as well ask them when you buy it.

Considering that you have to buy it or get a presciption from your VET anyways.. the vet should be able to advise on which dosage would be suitable for your dog.

That is a good question for your vet and will probably depend on your dog's breed, body condition (for example, if he's overweight, and should weight under 50 pounds, they might go with the smaller dose), and other factors. My dog was between sizes last time I refilled their heartworm meds. The receptionist had the vet come out, check his body condition, etc and they decided to go with the larger dose since he was still fairly young and they expected him to continue filling out a bit more, but it could just as easily go the other way. They also may be able to recommend a brand that your dog wouldn't be between doses with (such as perhaps Revolution, which comes in a 40 to 85 pound dose).

Good for you! Heartworm disease is so preventable and can be deadly! Is he still growing? If he is then go with the larger size. Is he losing weight because you have him on a diet and will he keep getting smaller? Then go with the smaller. How accurate is the scale? But if he was mine, I would go with the larger, it is safe and too little will not give him sufficient protection. When in doubt, ask your vet and follow his recommendation.

The vet will recommend going with the higher dose for heartgard. the toxic dose of ivermectin and pyrantel are SO much higher than the dose in the pills (pretty much unless you have a collie type dog, they could eat the whole box at once and be fine). but then if you go for the smaller dose, you dont know if it's actually enough. so, high dose.