Heartworm & Parasite Prevention for pets
Preventives for heartworm and common intestinal parasites.
Heartworm preventives are prescription-only in the US, because a dog must test negative before starting one. Giving a preventive to an already-infected dog can cause a serious reaction. Intestinal wormers vary — some are over the counter, some are not.
When to seek veterinary care
Heartworm preventives require a negative test and a veterinary prescription. Do not start, stop or change a preventive without your vet.
If this is an emergency, contact your veterinarian or an emergency animal hospital now — do not wait, and do not buy a product first. In the US, ASPCA Animal Poison Control is available 24/7 on (888) 426-4435.
When to contact a veterinarian
- Coughing, tiredness or reduced exercise tolerance
- A missed preventive dose — ask your vet about re-testing
Products shown below are commercial recommendations and are not a diagnosis or treatment plan.
Products in this category
No heartworm & parasite prevention products published yet
We publish a product only once its species suitability, warnings and ingredients have been checked against the manufacturer's own current information and dated. An unverified medical product is worse than none.
The category guides below explain what each type of product is for, and when a vet is the right answer instead.
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