Hiding after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 177 reports of hiding in dogs after Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

177Reports

41%Marked serious

39%Recovered

5.1%Died or euthanised

2 daysTypical onset

How soon it started

Same day

23 29%

1–2 days

17 22%

3–7 days

3 3.8%

1–4 weeks

11 14%

Over a month

24 31%

How the animals did

Recovered

65 37%

Recovered with lasting effects

4 2.3%

Still unwell when reported

18 10%

Died

7 4.0%

Euthanised

2 1.1%

Not known

81 46%

Problems reported at the same time

57 32%

51 29%

49 28%

46 26%

37 21%

28 16%

Restlessness or agitation

16 9.0%

Itching

16 9.0%

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 hiding in dogs?: 177 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 2 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).

Hiding with similar medicines

Hiding after Milbemycin Oxime + Spinosad (Trifexis) 198 reports · 0.2% of its reports
Hiding after Moxidectin (ProHeart 6) 119 reports · 0.2% of its reports
Hiding after Milbemycin Oxime + Praziquantel (Interceptor Plus) 65 reports · 0.2% of its reports
Hiding after Milbemycin Oxime (Interceptor) 45 reports · 0.2% of its reports
Hiding after Selamectin (Revolution) 91 reports · 0.3% of its reports
Hiding after Ivermectin (Heartgard) 21 reports · 0.2% of its reports
Hiding after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 21 reports · 0.2% of its reports

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