No sign after Ivermectin + Pyrantel (Heartgard Plus) in dogs

647 reports to the FDA describe no sign in dogs given Ivermectin + Pyrantel. That is 0.4% of all reports for this medicine, compared with 0.5% across reports for all dog medicines.

647Reports

71%Marked serious

57%Recovered

1.1%Died or euthanised

279 daysTypical onset

How soon it started

Same day

19 21%

1–2 days

3 3.4%

3–7 days

3 3.4%

1–4 weeks

4 4.5%

Over a month

60 67%

How the animals did

Recovered

30 4.6%

Recovered with lasting effects

340 53%

Still unwell when reported

7 1.1%

Died

7 1.1%

Not known

263 41%

Problems reported at the same time

Didn't prevent heartworm

443 68%

Didn't work as expected

36 5.6%

25 3.9%

23 3.6%

18 2.8%

14 2.2%

8 1.2%

7 1.1%

Age of the animals

Under 1 year

1–3 years

261

4–7 years

235

8–11 years

101

12+ years

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 no sign in dogs?: 647 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 279 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).

No sign with similar medicines

No sign after Milbemycin Oxime + Spinosad (Trifexis) 41 reports · 0.0% of its reports
No sign after Moxidectin (ProHeart 6) 25 reports · 0.0% of its reports
No sign after Milbemycin Oxime (Interceptor) 70 reports · 0.2% of its reports
No sign after Selamectin (Revolution) 316 reports · 1.1% of its reports
No sign after Ivermectin (Heartgard) 66 reports · 0.5% of its reports

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with no sign