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 if I miss a month of heartworm medication?
If it has been less than two weeks since the missed dose, give your dog the dose immediately. If it has been over two weeks since the missed dose, contact your vet, who will likely advise you to resume normal dosing next month and have the dog tested for heartworm in six months.
Can my dog go a month without heartworm medicine?
Annual testing is necessary, even when dogs are on heartworm prevention year-round, to ensure that the prevention program is working. Heartworm medications are highly effective, but dogs can still become infected. If you miss just one dose of a monthly medication—or give it late—it can leave your dog unprotected.
What happens if you miss 2 months of 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.
Can you give heartworm medicine every other month?
The monthly heartworm preventative we prescribe only lasts in a dog's or cat's body for one to two days, not 30 days, due to the lifestyle of the heartworm, it is only necessary for the pet to take the heartworm preventative every 30 days.
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