Breathing problems after Ivermectin + Pyrantel (Heartgard Plus) in dogs

1,458 reports to the FDA describe breathing problems in dogs given Ivermectin + Pyrantel. That is 1.0% of all reports for this medicine, compared with 2.7% across reports for all dog medicines, so it is reported less often than average with this medicine.

1,458Reports
59%Marked serious
30%Recovered
17%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
309 36%
1–2 days
111 13%
3–7 days
56 6.6%
1–4 weeks
117 14%
Over a month
258 30%

How the animals did

Recovered
423 29%
Recovered with lasting effects
21 1.4%
Still unwell when reported
164 11%
Died
162 11%
Euthanised
83 5.7%
Not known
605 41%

Problems reported at the same time

418 29%
316 22%
236 16%
189 13%
179 12%
162 11%

Age of the animals

Under 1 year
121
1–3 years
364
4–7 years
411
8–11 years
337
12+ years
187

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 breathing problems in dogs?
1,458 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 3 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).

Breathing problems with similar medicines

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