Heartgard Plus

Heartgard is a medicine made for heartworms in dogs and heartworm in cats. It also controls several other kinds of worms, including roundworms and hookworms. It is a chewable tablet that your dogs just eat. You can only administer it to dogs or puppies that are over 6 weeks old. You have to give the chewables to your pet once a month.

Heartgard's active ingredient is Ivermectin. It basically stops heartworms from growing into the larva stage, so they can never become adults and infest your pet. That doesn't do anything if your dog already has fully-grown heartworms, but it stops new ones from growing. Vets will usually test your dog or cat for heartworms first before prescribing this, and if they already have adult heartworms you will have to get them dewormed before you give it to them.


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Are there any side effects in dogs?

For the vast majority of dogs, no. Some dogs are more sensitive or will react badly to it. Watch for vomiting, diarrhea, or general lethargy. You should take your dog to the vet if you see these signs to make sure everything is OK.

Is it safe for collies?

This is one question that collie owners are somewhat worried about. Collies are more sensitive than other dogs to Ivermectin, the active ingredient in Heartgard Plus. This has led to some suggestions that Collies should not take any heartworm medicines. There are conflicting views on this. It is correct that Collies are more sensitive, but as seen here, they do not see problems until they hit around 10 times the recommended dose of Ivermectin. However, for a counter discussion, see here - while the studies emphatically show that it is safe, collie breeders occasionally report toxic reactions. The people who believe Ivermectin is dangerous to collies suggest using Interceptor instead.

Is there a version for Cats?

Yes - they make a version for cats as well. The one thing you should be aware of is that in cats heartworms are much less common than in dogs - it still occurs, but the heartworms are not very tailored to the bodies of cats and it is harder for them to survive.

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