Most of the monthly heartworm medicines have a safety factor of at least 15 days of protection if a dose is missed. This means that if you're just a week or two late, your pet is likely still within that window of protection and would be unlikely to become infected during that time.
Can dogs go without heartworm medicine?
Because of the way heart worms develop, the goal of heartworm meds is to kill the larvae before they grow up. But your dog's own immune system can do that … without drugs. That's the reason for focusing on the immune system … it's the first step in avoiding heartworm disease.
What happens if you forgot to give your dog heartworm medicine?
A dog who has missed just two monthly doses of preventative or is late for a heartworm injection can become infected with heartworms.
What happens if my dog misses a month of heartworm?
A: Give the dose you missed immediately, then continue giving the medication on the day you've always given it. If the missed dose is more than 2 weeks late, your dog should be tested for heartworm again in six months (click here to learn why).
What happens if you miss 2 months of heartworm medicine?
I have missed 2 months of heartworm prevention for my dog. What should I do? You need to consult your veterinarian, and immediately re-start your dog on monthly preventive—then retest your dog 6 months later.
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