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Smart is

not letting a bug bite turn deadly.


How dogs
get heartworms

One mosquito bite is all it takes to infect an unprotected dog with heartworms. In fact, nearly 300,000 indoor and outdoor dogs in the U.S. contract heartworms each year, causing painful heart and lung damage and even death.* Keep in mind that it’s easier and less expensive to prevent heartworms than to treat them.

Get smart about heartworms

  • Heartworms are transmitted by more than 70 species of mosquitoes.
  • Both indoor and outdoor dogs are at risk for heartworms year-round, in all 50 states.
  • Heartworms can grow up to 12 inches in length.
  • If left untreated, heartworms can prove fatal for a dog.
  • Symptoms include coughing, lack of energy, labored breathing and weight loss.
View heartworm FAQs


a heartworm medication that
protects against fleas, too.

Two Ways to Protect Your Dog

Both Sentinel® Spectrum® (milbemycin oxime/lufenuron/praziquantel) and Sentinel® (milbemycin oxime/lufenuron) Flavor Tabs® are smart and easy ways to treat and control heartworms. Just one tasty tablet, once a month protects your dog.

Always have your dog tested for heartworms by your veterinarian before starting a preventive regimen. Giving a preventive to a dog that is already heartworm-positive can cause further complications.

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Sentinel® Spectrum® (milbemycin oxime/lufenuron/praziquantel): Dogs should be tested for heartworm prior to use. Mild hypersensitivity reactions have been noted in some dogs carrying a high number of circulating microfilariae. Treatment with fewer than 6 monthly doses after the last exposure to mosquitoes may not provide complete heartworm prevention. Please see full product label for more information.