Have a question about parasites or PetTrust™ Plus (ivermectin/pyrantel)? Check the list below. If your question is not addressed, please feel free to contact us.

Using PetTrust™ Plus (ivermectin/pyrantel):

Does my dog really need PetTrust Plus every month?

Yes. The American Heartworm Society recommends treating your dog year-round.¹ Missing even one dose could put your pet at risk for serious diseases and infection, regardless of the time of year or your geographic location. PetTrust Plus chewable tablets must be administered on a monthly basis to keep your dog protected.

I forgot to give my dog a dose of PetTrust Plus. Should I give him one now?

Consult your veterinarian. If the interval between doses exceeds 30 days, the efficacy of heartworm prevention can be reduced. Continue administering PetTrust Plus monthly, but to be sure your dog is not infected, they should have a heartworm test in seven months. Heartworms must be approximately seven months old before the infection can be diagnosed.

Will my dog willingly take PetTrust Plus?

Studies have shown PetTrust Plus to be equally as palatable as HEARTGARD® Plus (ivermectin/pyrantel). Most dogs will take the chewable tablet from your hand, just like a treat.

Is PetTrust Plus safe for any dog breed?

PetTrust Plus is FDA-approved for all breeds of dogs. Certain dogs of the Collie breed are more sensitive to the effects of ivermectin administered at elevated dose levels (more than 16 times the target use level) than dogs of other breeds. Avoid elevated doses. Your veterinarian will prescribe the appropriate package for your dog’s weight. If you are in a multi-dog household, make sure to select the appropriate package for your dog’s weight. In a small percentage of dogs, digestive and neurological side effects have occurred.

My dog took more than one PetTrust Plus tablet within 30 days. What should I do?

Contact your veterinarian or local emergency clinic.

Can I give PetTrust Plus to my breeding dogs or their puppies?

PetTrust Plus is approved for use in pregnant or breeding females, stud dogs and puppies at least six weeks of age.

Can I give PetTrust Plus to my cat?

No. PetTrust Plus is only approved for dogs.

How and Where to Buy

Can PetTrust Plus be purchased without a prescription?

No. You must obtain a prescription from a veterinarian before purchasing PetTrust Plus.

How do I get a prescription for PetTrust Plus?

Visit your veterinarian for a heartworm test to ensure your dog is not currently infected. Then ask your veterinarian for a prescription for a 6- or 12-month supply of PetTrust Plus. Most veterinarians will give you a prescription to purchase at your local pharmacy once the test has been confirmed negative.

Where can I buy PetTrust Plus?

PetTrust Plus is available at your local Walmart and Sam’s Club pharmacies. Just take your pet’s prescription to the drop-off window and it will be filled like your own prescriptions.

Don’t I have to purchase my pet’s heartworm medicine from my veterinarian?

No. Once your dog has a prescription, it can be filled at a number of retail and online outlets.


What is heartworm disease?

Heartworm disease is a serious, sometimes fatal disease that is spread to pets by mosquitoes. As it progresses, parasitic worms grow and multiply in the arteries of your pet’s lungs and in the heart, causing damage to the pet’s internal organs.

How do pets get heartworm disease?

Heartworms (Dirofilaria immitis) need mosquitoes to develop and be transported from one infected pet to another. They cannot be spread directly from animal to animal without mosquitoes.

Is my dog breed susceptible to heartworms?

Yes. All unprotected dogs of all breeds are at risk for heartworm disease, regardless of age, sex or whether they are an indoor or outdoor dog.

Can my dog get heartworms where I live?

Yes. According to the American Heartworm Society™, cases of heartworm disease have been identified in all 50 states. States in the Southeast are at high risk because they have high mosquito populations.

What are the signs of heartworm disease?

Infected pets often show no clinical signs. In cases of heavy infections or in chronic cases, dogs may exhibit a mild, persistent cough, reluctance to move or exercise, fatigue, reduced appetite and weight loss. If your dog exhibits any of these signs, visit a veterinarian immediately.

What should I do if my dog is heartworm-positive?

Consult a veterinarian immediately for treatment options. They will help you determine a plan and understand health risks.

Can you treat dogs that are infected with heartworms?

Yes, but these treatments are risky, costly and often require hospitalization. Veterinarians must treat an infected dog by administering an adulticide to kill the adult worms. Masses of dead adult worms can cause a blockage of the heart, so treated dogs must be withheld from exercise and/or hospitalized for several months. Because of the cost and risk of treatment, it is much better to prevent infection than treat it.

What are roundworms?

Roundworms/ascarids (Toxocara canis, Toxascaris leonina) are common intestinal parasites that can be passed from mother dogs to puppies or contracted by eating wild animals or contaminated soil.

What are the signs of a roundworm infection?

Dogs with roundworms may exhibit a pot-bellied appearance, dry skin, hair loss, vomiting, gastric irritation, diarrhea and/or anemia. If your dog exhibits any of these signs, visit a veterinarian immediately.

What are hookworms?

Hookworms (Ancylostoma caninum, Ancylostoma braziliense, Uncinaria stenocephala) are intestinal parasites that feed on pets’ blood. They can be ingested through the mother’s milk, contaminated soil or feces and can also penetrate through the skin of a dog’s paws or belly.

What are the signs of a hookworm infection?

Hookworms can cause anemia, failure to gain weight, dehydration and/or diarrhea. Migration of hookworm larvae can also cause skin irritations, especially on the pet’s paws. If your dog exhibits any of these signs, visit a veterinarian immediately.

How do pets get intestinal parasites?

Roundworms and hookworms can be passed from mother dogs to puppies before they are born or ingested through the mother’s milk, wild animals or contaminated soil. Hookworms can also penetrate through the soft pads on pets’ paws.

Where can I find more information about parasites?

To learn more, visit the American Heartworm Society, the CDC or the Companion Animal Parasite Council™.

General Questions:

Should I give my dog a heartworm preventive all year round?

Yes. The American Heartworm Society recommends that heartworm preventives be administered year-round in the United States. Cases of heartworm disease have been diagnosed in winter months, even in cool climates.

What is a heartworm test?

A heartworm test is a simple blood test that allows veterinarians to detect the presence of heartworms. The test usually involves drawing just a few drops of blood from your dog and generally takes less than 10 minutes to get results.

How does PetTrust Plus prevent heartworms?

PetTrust Plus works by interrupting the life cycle of heartworms before they reach the adult stage.

How does PetTrust Plus control roundworms and/or hookworms?

Monthly administration of PetTrust Plus kills any adult roundworms and hookworms living in the intestines, so they can no longer reproduce.

How does PetTrust Plus compare to HEARTGARD® Plus?

PetTrust Plus has the same active ingredients and concentrations, and it’s just as effective against heartworms and intestinal parasites. PetTrust Plus is approved by the FDA as a generic version of HEARTGARD Plus.

Is PetTrust Plus covered by my pet health insurance?

Many pet health insurance providers do cover heartworm preventive medications. Consult your provider to confirm PetTrust Plus coverage and filing processes.

Are there any safety concerns with PetTrust Plus?

PetTrust Plus has shown a wide margin of safety at the recommended dose level in dogs. In clinical field trials with ivermectin/pyrantel, vomiting or diarrhea within 24 hours of dosing was rarely observed (1.1% of administered doses). The following adverse reactions have been reported: depression/lethargy, vomiting, anorexia, diarrhea, mydriasis, ataxia, staggering, convulsions and hypersalivation.

IMPORTANT INFORMATION: Dogs should be tested for heartworms prior to use. In a small percentage of treated dogs, digestive and neurological side effects may occur. Please see full product insert for more information.

¹American Heartworm Society