Heartworm prevention protects your pet from a mosquito-borne parasite that can be fatal if untreated. PetMeds carries 10 vet-recommended products — monthly chewables like Heartgard Plus, Interceptor Plus, and Sentinel Spectrum for dogs, topicals like Revolution Plus for cats, and the 12-month ProHeart 12 injection. Prescription options are verified by a licensed PharmD before shipping. Save 15% with AutoShip.
Every prescription verified by a licensed PharmD
Reviewed by Dr. Sarah Chen, PharmDThe best heartworm prevention depends on your pet's species, weight, lifestyle, and whether you prefer a monthly chewable, topical, or a long-acting injection. For dogs, vet-recommended options include Heartgard Plus, Interceptor Plus, Sentinel Spectrum, and ProHeart 12. For cats, Revolution Plus and Advantage Multi are the vet standard. Never use a dog heartworm product on a cat.
Answer three questions about your pet — species, size, and any known concerns — and the PetMeds heartworm finder will match you to the products that fit your pet's profile, ranked by vet recommendation and value.
Based on your pet's profile, these products match best.
The heartworm life cycle has four stages — mosquito, larvae, adult worm, and heart. A mosquito bites an infected animal and picks up microscopic heartworm larvae, which incubate inside the mosquito for 10–14 days. When that mosquito bites your pet, it deposits the larvae, which migrate through tissue for 1–3 months before maturing into adult worms 6–12 inches long. Adult heartworms live 5–7 years in the pulmonary arteries and heart. Monthly prevention kills the larvae before they reach the heart — which is why consistent dosing matters.
Heartworm is transmitted by mosquitoes, so risk tracks mosquito activity. In warm climates like the Gulf Coast and Southeast, mosquitoes are active year-round — heartworm risk never drops to zero. In cooler regions, mosquito season runs roughly April through October, but mosquitoes can survive indoors all winter. The American Heartworm Society recommends year-round prevention in all 50 states.
PetMeds carries 10 vet-recommended heartworm prevention products for dogs and cats. For dogs: Heartgard Plus, Interceptor Plus, Sentinel Spectrum, Simparica Trio, ProHeart 12, ProHeart 6, Iverhart Max, and Tri-Heart Plus. For cats: Revolution Plus and Advantage Multi. Prescription options are verified by a licensed PharmD. AutoShip saves 15% on every recurring order.
Heartworm prevention is safe when matched correctly to your pet. These five checks prevent the most common errors — and every PetMeds pharmacist is available at 1-800-738-6337 if you have a question.
Short, direct answers to the questions pet parents ask most.
Consistency beats catching up. Heartworm preventives work retroactively — they kill larvae from the last 30 days. Miss a dose and you create a risk gap. Test dogs over 7 months before starting. Never use a dog product on a cat. AutoShip ships every 30 days so you never miss a dose. Call 1-800-738-6337 to speak with a pharmacist about your pet.
Six core systems power every PetMeds order: the OMS order pipeline, Ordergroove for AutoShip subscriptions, the Vet Portal for prescription verification, Iterable for customer messaging, Salesforce Service Cloud for support cases, and the PIM for product data. Prescription heartworm products like Heartgard Plus and ProHeart 12 are verified by a licensed PharmD before shipping.