Tachycardia after Ivermectin + Pyrantel (Heartgard Plus) in dogs

204 reports to the FDA describe tachycardia in dogs given Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.5% across reports for all dog medicines, so it is reported less often than average with this medicine.

204Reports

58%Marked serious

20%Recovered

18%Died or euthanised

14 daysTypical onset

How soon it started

Same day

27 26%

1–2 days

14 14%

3–7 days

5 4.9%

1–4 weeks

15 15%

Over a month

41 40%

How the animals did

Recovered

37 18%

Recovered with lasting effects

4 2.0%

Still unwell when reported

26 13%

Died

23 11%

Euthanised

14 6.9%

Not known

100 49%

Problems reported at the same time

73 36%

71 35%

70 34%

41 20%

40 20%

37 18%

36 18%

Restlessness or agitation

33 16%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

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 tachycardia in dogs?: 204 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).

Tachycardia with similar medicines

Tachycardia after Milbemycin Oxime + Spinosad (Trifexis) 209 reports · 0.2% of its reports
Tachycardia after Moxidectin (ProHeart 6) 628 reports · 1.2% of its reports
Tachycardia after Milbemycin Oxime + Praziquantel (Interceptor Plus) 55 reports · 0.2% of its reports
Tachycardia after Milbemycin Oxime (Interceptor) 78 reports · 0.3% of its reports
Tachycardia after Selamectin (Revolution) 86 reports · 0.3% of its reports
Tachycardia after Ivermectin (Heartgard) 82 reports · 0.7% of its reports
Tachycardia after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 32 reports · 0.4% of its reports

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