The common consensus is that it takes about 40‒50 days for heartworm larvae to mature to the point where heartworm preventatives no longer work.
How Long Can dogs go without heartworm pills?
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.
What happens if my dog misses a month of heartworm?
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 dog doesn't take heartworm?
Heartworm disease is a very serious parasitic disease that has the potential to be fatal for your dog if he is not treated quickly. This parasite is a worm that can grow up to a foot long and lives inside the heart, lungs, and associated blood vessels of an infected animal where it will reproduce over and over.
How late can you give heartworm medicine to dogs?
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).
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Can my dog miss a month of Heartgard?What happens if you forgot to give your dog heartworm medicine?
