Death after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 2,810 reports of death in dogs after Ivermectin + Pyrantel. That is 1.9% of all reports for this medicine, compared with 5.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

2,810Reports

81%Marked serious

0.1%Recovered

99%Died or euthanised

14 daysTypical onset

How soon it started

Same day

304 21%

1–2 days

163 11%

3–7 days

137 9.3%

1–4 weeks

512 35%

Over a month

363 25%

How the animals did

Recovered

3 0.1%

Recovered with lasting effects

1 0.0%

Still unwell when reported

4 0.1%

Died

1,889 67%

Euthanised

895 32%

Not known

18 0.6%

Problems reported at the same time

Vomiting

448 16%

Lethargy

421 15%

Loss of appetite

375 13%

Didn't prevent heartworm

300 11%

296 11%

237 8.4%

236 8.4%

212 7.5%

Age of the animals

Under 1 year

186

1–3 years

325

4–7 years

403

8–11 years

602

12+ years

590

About this medicine

Ivermectin prevents heartworm disease (monthly). Pyrantel treats roundworms and hookworms.

Products with this combination include Heartgard Plus, Tri-Heart Plus, Iverhart Plus. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Some herding breeds (for example Collies) carry the MDR1 gene variant and can be more sensitive to this drug class at high doses.

Questions owners ask

Can Ivermectin + Pyrantel cause death in dogs?: 2,810 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 14 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Death with similar medicines

Death after Milbemycin Oxime + Spinosad (Trifexis) 3,307 reports · 2.5% of its reports
Death after Moxidectin (ProHeart 6) 2,447 reports · 4.8% of its reports
Death after Milbemycin Oxime + Praziquantel (Interceptor Plus) 920 reports · 2.9% of its reports
Death after Milbemycin Oxime (Interceptor) 1,015 reports · 3.4% of its reports
Death after Selamectin (Revolution) 785 reports · 2.7% of its reports
Death after Ivermectin (Heartgard) 609 reports · 5.1% of its reports
Death after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 125 reports · 1.5% of its reports
Death after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 60 reports · 5.2% of its reports

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with death