Anxiety after Ivermectin + Pyrantel (Heartgard Plus) in dogs

382 reports to the FDA describe anxiety in dogs given Ivermectin + Pyrantel. That is 0.3% of all reports for this medicine, compared with 0.5% across reports for all dog medicines, so it is reported less often than average with this medicine.

382Reports

57%Marked serious

42%Recovered

2.9%Died or euthanised

2 daysTypical onset

How soon it started

Same day

88 35%

1–2 days

39 15%

3–7 days

14 5.5%

1–4 weeks

29 11%

Over a month

83 33%

How the animals did

Recovered

157 41%

Recovered with lasting effects

4 1.0%

Still unwell when reported

35 9.2%

Died

3 0.8%

Euthanised

8 2.1%

Not known

175 46%

Problems reported at the same time

Behaviour change

110 29%

Breathing problems

86 23%

Vomiting

74 19%

Restlessness or agitation

71 19%

66 17%

55 14%

50 13%

43 11%

Age of the animals

Under 1 year

1–3 years

119

4–7 years

108

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 anxiety in dogs?: 382 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).

Anxiety with similar medicines

Anxiety after Milbemycin Oxime + Spinosad (Trifexis) 623 reports · 0.5% of its reports
Anxiety after Moxidectin (ProHeart 6) 156 reports · 0.3% of its reports
Anxiety after Milbemycin Oxime + Praziquantel (Interceptor Plus) 194 reports · 0.6% of its reports
Anxiety after Milbemycin Oxime (Interceptor) 70 reports · 0.2% of its reports
Anxiety after Selamectin (Revolution) 54 reports · 0.2% of its reports
Anxiety after Ivermectin (Heartgard) 75 reports · 0.6% of its reports
Anxiety after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 30 reports · 0.4% of its reports

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