Heartworm preventative Heartgard Plus

Along with monthly Sentinel, Heartgard Plus is among the most commonly prescribed monthly heartworm preventatives by veterinarians.  While both are very effective against protecting against heartworms, Heartgard seems slightly more effective in treating and preventing roundworms and hookworms, while Sentinel offers the protection against whipworms, which occur more sporadically across the United States.

Heartgard Plus heartworm preventative Puppies and/or kittens can be safely started on Heartgard typically at age 8-12 weeks, especially important during a time when roundworms and hookworm infestations are common.  Heartgard Plus does seem to have a long shelf life of 1-2 years. It comes in very convenient dosing package sizes of up to 25 pound dogs, 26 to 50 pound packaging/dosing, and 51-100 pound packaging and dosing.   It is quite safe to use the up to 25 pound size even in small breeds, as owners often wonder if splitting the pill is needed in toy breeds, which is not necessary.

Side effects are indeed rare, but on occasion pets can have rare digestive, dermatologic, and even more rare neurological side effects.  If any of these should occur, I would ask your veterinarian for a prescription for monthly Sentinel as an alternative. It is safe to be on  Heartgard Plus if another dewormer is needed in a dog, such as Panacur C.

Related Posts


  1. What should I use to treat whipworm preventatively if my dog is already on heartguard plus?

  2. Hi KDV. We always recommend you consult your physician to determine the best course of treatment. You are also welcome to submit your question using our Ask the Vet form: https://www.1800petmeds.com/education/ask-the-vet-form.html. I hope that helps! ~Leah, PetMeds Pro

  3. I have a German Shepard and his weight is around 158lbs, so with that speaking would you give my boy 1 1/2 tab.

    Also what is the expiration date on them. I have found some from the year before and it says VBD1500 and under that it has 06-2020?

Leave a Comment