Breathing problems after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) in dogs

The FDA has received 231 reports of breathing problems in dogs after Ivermectin + Praziquantel + Pyrantel. That is 2.7% of all reports for this medicine, compared with 2.7% across reports for all dog medicines.

231Reports
49%Marked serious
51%Recovered
6.5%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
144 77%
1–2 days
24 13%
3–7 days
5 2.7%
1–4 weeks
3 1.6%
Over a month
10 5.4%

How the animals did

Recovered
115 50%
Recovered with lasting effects
2 0.9%
Still unwell when reported
7 3.0%
Died
11 4.8%
Euthanised
4 1.7%
Not known
92 40%

Problems reported at the same time

Age of the animals

Under 1 year
12
1–3 years
74
4–7 years
80
8–11 years
34
12+ years
23

About this medicine

Ivermectin prevents heartworm disease (monthly). Praziquantel treats tapeworms. Pyrantel treats roundworms and hookworms.

Products with this combination include Iverhart Max. 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 + Praziquantel + Pyrantel cause breathing problems in dogs?
231 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 the same 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).

Breathing problems with similar medicines

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