Disorientation after Ivermectin + Pyrantel (Heartgard Plus) in dogs

588 reports to the FDA describe disorientation in dogs given Ivermectin + Pyrantel. That is 0.4% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported less often than average with this medicine.

588Reports

48%Marked serious

38%Recovered

8.2%Died or euthanised

4 daysTypical onset

How soon it started

Same day

99 29%

1–2 days

52 15%

3–7 days

35 10%

1–4 weeks

49 15%

Over a month

101 30%

How the animals did

Recovered

218 37%

Recovered with lasting effects

6 1.0%

Still unwell when reported

63 11%

Died

23 3.9%

Euthanised

25 4.3%

Not known

253 43%

Problems reported at the same time

212 36%

166 28%

129 22%

122 21%

120 20%

95 16%

89 15%

65 11%

Age of the animals

Under 1 year

1–3 years

160

4–7 years

150

8–11 years

113

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 disorientation in dogs?: 588 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 4 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).

Disorientation with similar medicines

Disorientation after Milbemycin Oxime + Spinosad (Trifexis) 1,317 reports · 1.0% of its reports
Disorientation after Moxidectin (ProHeart 6) 293 reports · 0.6% of its reports
Disorientation after Milbemycin Oxime + Praziquantel (Interceptor Plus) 183 reports · 0.6% of its reports
Disorientation after Milbemycin Oxime (Interceptor) 154 reports · 0.5% of its reports
Disorientation after Selamectin (Revolution) 202 reports · 0.7% of its reports
Disorientation after Ivermectin (Heartgard) 246 reports · 2.0% of its reports
Disorientation after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 45 reports · 0.5% of its reports

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