Inappropriate urination after Ivermectin (Heartgard) in dogs

The FDA has received 60 reports of inappropriate urination in dogs after Ivermectin. That is 0.5% of all reports for this medicine, compared with 0.5% across reports for all dog medicines.

60Reports

43%Marked serious

52%Recovered

12%Died or euthanised

40 daysTypical onset

How soon it started

Same day

7 18%

1–2 days

4 10%

3–7 days

2 5.0%

1–4 weeks

6 15%

Over a month

21 53%

How the animals did

Recovered

26 43%

Recovered with lasting effects

5 8.3%

Still unwell when reported

12 20%

Died

2 3.3%

Euthanised

5 8.3%

Not known

10 17%

Problems reported at the same time

18 30%

17 28%

15 25%

11 18%

10 17%

10 17%

9 15%

9 15%

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).

Products with this ingredient include Heartgard. 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 cause inappropriate urination in dogs?: 60 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 40 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).

Inappropriate urination with similar medicines

Inappropriate urination after Ivermectin + Pyrantel (Heartgard Plus) 352 reports · 0.2% of its reports
Inappropriate urination after Milbemycin Oxime + Spinosad (Trifexis) 494 reports · 0.4% of its reports
Inappropriate urination after Moxidectin (ProHeart 6) 168 reports · 0.3% of its reports
Inappropriate urination after Milbemycin Oxime + Praziquantel (Interceptor Plus) 124 reports · 0.4% of its reports
Inappropriate urination after Milbemycin Oxime (Interceptor) 34 reports · 0.1% of its reports
Inappropriate urination after Selamectin (Revolution) 35 reports · 0.1% of its reports
Inappropriate urination after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 20 reports · 0.2% of its reports

All reported side effects of Ivermectin in dogs · Medicines most reported with inappropriate urination