From the FDA Drug Label
For the prevention of heartworm disease, Selamectin must be administered on a monthly basis. Selamectin may be administered year-round or at least within one month after the animal's first exposure to mosquitoes and monthly thereafter until the end of the mosquito season. For the prevention and control of flea infestations, Selamectin should be administered at monthly intervals throughout the flea season, starting one month before fleas become active. For the control of tick (Dermacentor variabilis) infestations in dogs, Selamectin should be administered on a monthly basis.
The FDA drug label recommends starting heartworm, flea, and tick prevention:
- At least within one month after the animal's first exposure to mosquitoes for heartworm prevention.
- One month before fleas become active for flea prevention.
- On a monthly basis for tick control in dogs. It is recommended to start prevention when the animal is 6 weeks of age and older for dogs and 8 weeks of age and older for cats 1.
From the Research
You should start heartworm, flea, and tick prevention for your pet year-round, beginning when they are puppies or kittens (typically at 6-8 weeks of age). This is based on the most recent evidence from 2, which highlights the importance of year-round prevention to protect against heartworm disease, fleas, and ticks.
Key Considerations
- Heartworm disease can cause severe heart and lung damage, and fleas and ticks can transmit diseases like Lyme disease, ehrlichiosis, and tapeworms.
- Inconsistent protection can create vulnerability windows, even in colder months when these parasites seem less active.
- Common heartworm preventatives include Heartgard Plus (ivermectin/pyrantel), Interceptor (milbemycin oxime), and ProHeart injections (moxidectin), while effective flea and tick products include Frontline Plus (fipronil/methoprene), Nexgard (afoxolaner), Bravecto (fluralaner), and Seresto collars (imidacloprid/flumethrin) as mentioned in 3 and 4.
Product Efficacy
- The combination of imidacloprid/moxidectin was 100% effective in preventing development of the JYD-34 laboratory strain of D. immitis in dogs following a single treatment, as shown in 3.
- Other products, such as ivermectin/pyrantel pamoate, milbemycin oxime/spinosad, and selamectin, provided less than 100% efficacy in the same study.
Consultation with a Veterinarian
- It is essential to consult with a veterinarian to determine the most appropriate products for your pet based on their age, weight, health status, and local parasite risks, as emphasized in 5 and 6.
Resistance and Treatment
- Resistance to available heartworm preventives is a concern, and understanding factors that promote resistance is crucial to maintaining control, as discussed in 2.
- Treatment of heartworm disease should be done under the guidance of a veterinarian, and preventative measures should be taken to avoid resistance, as mentioned in 5 and 6.