Swelling after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 839 reports of swelling in dogs after Ivermectin + Pyrantel. That is 0.6% of all reports for this medicine, compared with 2.8% across reports for all dog medicines, so it is reported less often than average with this medicine.

839Reports

48%Marked serious

26%Recovered

8.6%Died or euthanised

9 daysTypical onset

How soon it started

Same day

135 28%

1–2 days

74 15%

3–7 days

32 6.6%

1–4 weeks

79 16%

Over a month

166 34%

How the animals did

Recovered

212 25%

Recovered with lasting effects

7 0.8%

Still unwell when reported

121 14%

Died

41 4.9%

Euthanised

31 3.7%

Not known

427 51%

Problems reported at the same time

217 26%

169 20%

129 15%

113 13%

85 10%

84 10%

71 8.5%

68 8.1%

Age of the animals

Under 1 year

167

1–3 years

284

4–7 years

227

8–11 years

101

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 swelling in dogs?: 839 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 9 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).

Swelling with similar medicines

Swelling after Milbemycin Oxime + Spinosad (Trifexis) 959 reports · 0.7% of its reports
Swelling after Moxidectin (ProHeart 6) 7,913 reports · 16% of its reports
Swelling after Milbemycin Oxime + Praziquantel (Interceptor Plus) 371 reports · 1.2% of its reports
Swelling after Milbemycin Oxime (Interceptor) 257 reports · 0.9% of its reports
Swelling after Selamectin (Revolution) 410 reports · 1.4% of its reports
Swelling after Ivermectin (Heartgard) 204 reports · 1.7% of its reports
Swelling after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 66 reports · 0.8% of its reports
Swelling after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 22 reports · 1.9% of its reports

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