Urine abnormalities after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 74 reports of urine abnormalities in dogs after Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

74Reports

64%Marked serious

23%Recovered

9.5%Died or euthanised

32 daysTypical onset

How soon it started

Same day

7 15%

1–2 days

5 11%

3–7 days

3 6.5%

1–4 weeks

7 15%

Over a month

24 52%

How the animals did

Recovered

16 22%

Recovered with lasting effects

1 1.4%

Still unwell when reported

16 22%

Died

2 2.7%

Euthanised

5 6.8%

Not known

34 46%

Problems reported at the same time

32 43%

31 42%

27 36%

23 31%

23 31%

18 24%

18 24%

16 22%

Age of the animals

Under 1 year

1–3 years

4–7 years

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 urine abnormalities in dogs?: 74 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 32 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).

Urine abnormalities with similar medicines

Urine abnormalities after Milbemycin Oxime + Spinosad (Trifexis) 210 reports · 0.2% of its reports
Urine abnormalities after Moxidectin (ProHeart 6) 59 reports · 0.1% of its reports
Urine abnormalities after Milbemycin Oxime + Praziquantel (Interceptor Plus) 58 reports · 0.2% of its reports
Urine abnormalities after Milbemycin Oxime (Interceptor) 20 reports · 0.1% of its reports
Urine abnormalities after Ivermectin (Heartgard) 27 reports · 0.2% of its reports

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