Do heartworm medicines kill or just prevent heartworms?

There is a variety of dog medication available online that both prevent heartworm disease and flea and tick infestation. However, if you're asking about the medicine prescribed to dogs already diagnosed with the disease, I don't believe that was formulated for tick and flea prevention.

In the end, it all boils down to "ask your vet first". Dosage is very important especially when it comes to heartworm meds so this is your best bet. I'm sure your pet's life is not something you'd take chances on.

=== === == Heart worm medicine only works on heartworms not fleas or ticks.