Ivermectin + Pyrantel Pamoate (Heartgard Plus, Iverhart Plus): adverse event reports that FDA received

Signs that the reports list

A sign is a coded term from the report. The words in brackets are a plain gloss of the term. The percentage is the share of the 162,847 reports that list the sign. One report can list more than one sign.

The sign that is in the largest number of the reports comes first.

1. Ineffective, heartworm larvae[legacy FDA term: the product did not have the expected effect (heartworm larvae)]21.2%34,604 reports
2. Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]15.6%25,355 reports
3. Lack of efficacy (endoparasite) - heartworm[the product did not have the expected effect: heartworm]14%22,771 reports
4. Vomiting10.8%17,641 reports
5. Digestive tract disorder NOS[digestive problem, type not specified]10.2%16,537 reports
6. Ineffective, ascarids NOS[legacy FDA term: the product did not have the expected effect (ascarids nos)]6.9%11,261 reports
7. Cardiac disorder NOS[heart problem, type not specified]6.2%10,040 reports
8. Diarrhoea[diarrhea]5%8,178 reports
9. Tablets, Abnormal[a product quality report, not a sign in an animal]4.8%7,765 reports
10. Lack of efficacy - NOS[the product did not have the expected effect]4.6%7,425 reports
11. Ineffective, hooks[legacy FDA term: the product did not have the expected effect (hooks)]4.2%6,845 reports
12. Lethargy[unusually tired or inactive]3.5%5,738 reports
13. Lack of efficacy (endoparasite) - roundworm NOS[the product did not have the expected effect: roundworms]3.1%5,073 reports
14. Containers, Damaged[a product quality report, not a sign in an animal]2%3,237 reports

The list shows 30 of 2,020 coded signs. A report is not proof that a drug caused a sign. Download all signs (CSV)

Reports by species

• Dog90.7%147,762
• Catunder 0.1%66
• Human exposureunder 0.1%57
• Otherunder 0.1%13
• Other Canidsunder 0.1%8
• Macawunder 0.1%3

The share is of all 162,847 reports that name ivermectin + pyrantel pamoate. The other reports give a different species or no species.

Reports for each month, Jul 2021 to Jun 2026

The month is the month in which FDA received the report. Each chart has its own scale. FDA says that a report can take 3 to 6 months to reach the public data. The newest months can get more reports in a later update.

Reports by year

• Dog
• Cat
• Horse
• Other or not given

2026 has the reports that FDA received through Jun 2026. Download the years (CSV)

What the reports record

Each bar is on a scale of 0 to 100%.

Other pages with one of these ingredients

A report names a drug by its set of active ingredients. Each set has its own page. The list is in order of name.

• Ivermectin, all combinations
• Pyrantel Pamoate, all combinations
• Afoxolaner + Moxidectin + Pyrantel Pamoate
• Clorsulon + Ivermectin
• Febantel + Praziquantel + Pyrantel Pamoate
• Ivermectin
• Ivermectin + Praziquantel
• Ivermectin + Praziquantel + Pyrantel Pamoate
• Lotilaner + Moxidectin + Praziquantel + Pyrantel Pamoate
• Moxidectin + Pyrantel Pamoate + Sarolaner
• Praziquantel + Pyrantel Pamoate
• Pyrantel Pamoate
• Pyrantel Pamoate + Sarolaner

Next in the A to Z list

• Itraconazole
• Ketamine Hydrochloride
• Ketoconazole
• Ketoprofen
• Ketoprofen + Tulathromycin

All drugs by active ingredient. Brand names A to Z

FDA pages for this drug

• How to Report Animal Drug and Device Side Effects and Product ProblemsThe FDA page that tells an owner or a veterinarian how to send a report.
• Green Book record of NADA 140-971The FDA record of the application for Heartgard Plus.
• Green Book record of ANADA 200-302The FDA record of the application for Iverhart Plus Flavored Chewables.
• Green Book record of ANADA 200-338The FDA record of the application for Tri-Heart Plus Chewable Tablets.
• Animal Drugs @ FDAThe search page of the Green Book, the FDA list of approved animal drugs.

The site checked these addresses on 2 Oct 2026. The links open in a new tab.

Cite this page

Pet Drug Reports. Ivermectin + Pyrantel Pamoate: adverse event reports that FDA received. https://petdrugreports.com/drug/ivermectin-pyrantel-pamoate/ Source: FDA Center for Veterinary Medicine, openFDA Animal and Veterinary adverse event reports, export of 30 Oct 2026. Reports received through 26 Jun 2026.

Where the data come from

Questions about these reports

Which brand are these reports about?

The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand. The Green Book section of this page lists the brand names with these active ingredients.

Do the reports show that the drug caused the signs?

No. FDA states this about the data.

When looking at the results, be aware that there is no certainty that the reported drug or device caused the adverse event.

The adverse event may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources.

FDA Center for Veterinary Medicine. Source: Adverse Event Reports for Animal Drugs and Devices

How many reports did FDA receive in the latest 12 months?

FDA received 4,550 reports in the 12 months to June 2026. It received 5,455 reports in the 12 months before. FDA says that a report can take 3 to 6 months to reach the public data. The newest months can get more reports in a later update.

What kinds of report are in the count?

Of the 162,847 reports received from September 1993 to June 2026, 41.2% are about a safety issue only. 49.3% are about a lack of expected effectiveness, alone or with a safety issue. 9.5% are about a defect of the product or its package.