Allergic reaction after Ivermectin + Pyrantel (Heartgard Plus) in dogs

788 reports to the FDA describe allergic reaction in dogs given Ivermectin + Pyrantel. That is 0.5% of all reports for this medicine, compared with 2.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

788Reports

43%Marked serious

31%Recovered

3.7%Died or euthanised

1 daysTypical onset

How soon it started

Same day

156 36%

1–2 days

84 19%

3–7 days

24 5.5%

1–4 weeks

58 13%

Over a month

114 26%

How the animals did

Recovered

236 30%

Recovered with lasting effects

6 0.8%

Still unwell when reported

107 14%

Died

20 2.5%

Euthanised

9 1.1%

Not known

410 52%

Problems reported at the same time

217 28%

181 23%

177 22%

105 13%

89 11%

64 8.1%

Skin rash or irritation

50 6.3%

Skin redness

49 6.2%

Age of the animals

Under 1 year

124

1–3 years

310

4–7 years

211

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 allergic reaction in dogs?: 788 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 1 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).

Allergic reaction with similar medicines

Allergic reaction after Milbemycin Oxime + Spinosad (Trifexis) 1,103 reports · 0.9% of its reports
Allergic reaction after Moxidectin (ProHeart 6) 9,936 reports · 20% of its reports
Allergic reaction after Milbemycin Oxime + Praziquantel (Interceptor Plus) 402 reports · 1.3% of its reports
Allergic reaction after Milbemycin Oxime (Interceptor) 274 reports · 0.9% of its reports
Allergic reaction after Selamectin (Revolution) 473 reports · 1.6% of its reports
Allergic reaction after Ivermectin (Heartgard) 160 reports · 1.3% of its reports
Allergic reaction after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 70 reports · 0.8% of its reports

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