What To Do When You’ve Missed Your Pet’s Heartworm Preventative Dose

Does My Pet Need to Be Tested for HeartWorms?

Missed a dose of your pet's heartworm preventative? Immediately testing for heartworms isn't necessary

A common question animal guardians will often ask is that if they miss a month of heartworm medicine, what do they need to do? Many times clients are told inappropriate information by both their friends and even some veterinarians. It is not necessary to have a pet immediately tested for heartworms if they have missed a month of heartworm medicine. The reason for this is because it takes at least 6 months for a dog to become heartworm-positive if he or she is bitten by mosquitoes carrying heartworms. Also, most of the monthly heartworm medicines have a safety factor of at least 15 days of protection if a dose is missed.

The simplest answer to those who miss a month of heartworm prevention is just to give the pill and restart their monthly preventative schedule. At the time of an annual or semiannual exam a routine blood heartworm test is recommended, along with their pets’ wellness exam and/or vaccinations and other laboratory testing if appropriate for an individual pet. While I encourage animal guardians to maintain their monthly heartworm preventative scheduling, accidentally missing a dose will not be a health risk or harmful to their pets in these isolated circumstances.


Missing Heartworm Dosage: Resume Heartworm Preventative Administration

In the prior blog I addressed the question about what an animal guardian should do if they miss a dose of heartworm pet medicine. As mentioned, simply resuming monthly administration is the answer in most cases. The reason why animal guardians should not just pick and choose their own schedule of monthly heartworm medication administration is that it is hard to predict when heartworm transmission season ends or begins in many areas of the country.

If you miss a dose of heartworm pet meds, it is best to resume the medication as soon as possible

With the recent tendency to global warming, heartworm-carrying mosquitoes have been seen even in colder months in some areas. Also many animal guardians will forget to start up heartworm preventative medication, if left to decide on their own, as well as the fact that irregular use of many medicines such as prescribed antibiotics and/or parasitic medication may be associated with the development of resistant strains of parasites, which is a recent concern even with heartworm medication that is currently being looked at more closely.

Also most of the monthly oral heartworm medicines like Interceptor or Heartgard helps control and prevent other parasites such as intestinal worms, which can occur any time of year in most areas of the country.