Tachycardia after Ivermectin (Heartgard) in dogs

82 reports to the FDA describe tachycardia in dogs given Ivermectin. That is 0.7% of all reports for this medicine, compared with 0.5% across reports for all dog medicines.

82Reports

35%Marked serious

18%Recovered

23%Died or euthanised

14 daysTypical onset

How soon it started

Same day

9 29%

1–2 days

1 3.2%

3–7 days

3 9.7%

1–4 weeks

6 19%

Over a month

12 39%

How the animals did

Recovered

12 15%

Recovered with lasting effects

3 3.7%

Still unwell when reported

8 9.8%

Died

14 17%

Euthanised

5 6.1%

Not known

40 49%

Problems reported at the same time

Wobbliness (ataxia)

32 39%

Tremors

30 37%

Eye or vision problems

27 33%

25 30%

25 30%

24 29%

22 27%

19 23%

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).

Products with this ingredient include Heartgard. 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 cause tachycardia in dogs?: 82 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 Ivermectin + Pyrantel (Heartgard Plus) 204 reports · 0.1% of its reports
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 + Praziquantel + Pyrantel (Iverhart Max) 32 reports · 0.4% of its reports

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