Sleepiness - systemic disorder after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 75 reports of sleepiness - systemic disorder 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, so it is reported less often than average with this medicine.

75Reports

23%Marked serious

31%Recovered

9.3%Died or euthanised

Same dayTypical onset

How soon it started

Same day

32 53%

1–2 days

11 18%

3–7 days

2 3.3%

1–4 weeks

6 10%

Over a month

9 15%

How the animals did

Recovered

23 31%

Still unwell when reported

8 11%

Died

2 2.7%

Euthanised

5 6.7%

Not known

37 49%

Problems reported at the same time

22 29%

21 28%

14 19%

11 15%

10 13%

7 9.3%

6 8.0%

6 8.0%

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 sleepiness - systemic disorder in dogs?: 75 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 the same day 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).

Sleepiness - systemic disorder with similar medicines

Sleepiness - systemic disorder after Milbemycin Oxime + Spinosad (Trifexis) 99 reports · 0.1% of its reports
Sleepiness - systemic disorder after Moxidectin (ProHeart 6) 32 reports · 0.1% of its reports
Sleepiness - systemic disorder after Milbemycin Oxime + Praziquantel (Interceptor Plus) 81 reports · 0.3% of its reports

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with sleepiness - systemic disorder