Flatulence after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 150 reports of flatulence in dogs after Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

150Reports

49%Marked serious

27%Recovered

0.7%Died or euthanised

11 daysTypical onset

How soon it started

Same day

24 36%

1–2 days

7 10%

3–7 days

1 1.5%

1–4 weeks

10 15%

Over a month

25 37%

How the animals did

Recovered

41 27%

Still unwell when reported

10 6.7%

Euthanised

1 0.7%

Not known

98 65%

Problems reported at the same time

56 37%

45 30%

33 22%

28 19%

26 17%

26 17%

Digestive tract disorder

25 17%

Didn't work as expected

20 13%

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 flatulence in dogs?: 150 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 11 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).

Flatulence with similar medicines

Flatulence after Milbemycin Oxime + Spinosad (Trifexis) 115 reports · 0.1% of its reports
Flatulence after Moxidectin (ProHeart 6) 29 reports · 0.1% of its reports
Flatulence after Milbemycin Oxime + Praziquantel (Interceptor Plus) 56 reports · 0.2% of its reports
Flatulence after Milbemycin Oxime (Interceptor) 59 reports · 0.2% of its reports
Flatulence after Selamectin (Revolution) 26 reports · 0.1% of its reports

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