Lethargy after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) in dogs

969 reports to the FDA describe lethargy in dogs given Ivermectin + Praziquantel + Pyrantel. That is 11% of all reports for this medicine, compared with 11% across reports for all dog medicines.

969Reports

25%Marked serious

50%Recovered

4.1%Died or euthanised

Same dayTypical onset

How soon it started

Same day

527 74%

1–2 days

84 12%

3–7 days

26 3.7%

1–4 weeks

25 3.5%

Over a month

48 6.8%

How the animals did

Recovered

476 49%

Recovered with lasting effects

5 0.5%

Still unwell when reported

21 2.2%

Died

28 2.9%

Euthanised

12 1.2%

Not known

427 44%

Problems reported at the same time

568 59%

222 23%

210 22%

101 10%

80 8.3%

67 6.9%

59 6.1%

57 5.9%

Age of the animals

Under 1 year

1–3 years

379

4–7 years

286

8–11 years

130

12+ years

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 lethargy in dogs?: 969 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).

Lethargy with similar medicines

Lethargy after Ivermectin + Pyrantel (Heartgard Plus) 7,391 reports · 5.0% of its reports
Lethargy after Milbemycin Oxime + Spinosad (Trifexis) 19,835 reports · 15% of its reports
Lethargy after Moxidectin (ProHeart 6) 6,640 reports · 13% of its reports
Lethargy after Milbemycin Oxime + Praziquantel (Interceptor Plus) 2,407 reports · 7.6% of its reports
Lethargy after Milbemycin Oxime (Interceptor) 2,528 reports · 8.5% of its reports
Lethargy after Selamectin (Revolution) 2,964 reports · 10% of its reports
Lethargy after Ivermectin (Heartgard) 1,488 reports · 12% of its reports
Lethargy after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 135 reports · 12% of its reports
Lethargy after Ivermectin + Praziquantel 35 reports · 17% of its reports
Lethargy after Moxidectin + Praziquantel 21 reports · 28% of its reports

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