Foaming at the mouth after Ivermectin (Heartgard) in dogs

21 reports to the FDA describe foaming at the mouth in dogs given Ivermectin. That is 0.2% of all reports for this medicine, compared with 0.2% across reports for all dog medicines.

21Reports

76%Marked serious

48%Recovered

19%Died or euthanised

50 daysTypical onset

How soon it started

Same day

4 25%

1–2 days

2 13%

3–7 days

0 0.0%

1–4 weeks

2 13%

Over a month

8 50%

How the animals did

Recovered

7 33%

Recovered with lasting effects

3 14%

Still unwell when reported

5 24%

Died

2 9.5%

Euthanised

2 9.5%

Not known

2 9.5%

Problems reported at the same time

11 52%

6 29%

6 29%

5 24%

5 24%

Restlessness or agitation

5 24%

Itching

5 24%

Lethargy

5 24%

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 foaming at the mouth in dogs?: 21 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 50 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).

Foaming at the mouth with similar medicines

Foaming at the mouth after Ivermectin + Pyrantel (Heartgard Plus) 224 reports · 0.2% of its reports
Foaming at the mouth after Milbemycin Oxime + Spinosad (Trifexis) 221 reports · 0.2% of its reports
Foaming at the mouth after Moxidectin (ProHeart 6) 34 reports · 0.1% of its reports
Foaming at the mouth after Milbemycin Oxime + Praziquantel (Interceptor Plus) 62 reports · 0.2% of its reports
Foaming at the mouth after Selamectin (Revolution) 32 reports · 0.1% of its reports

All reported side effects of Ivermectin in dogs · Medicines most reported with foaming at the mouth