Excessive thirst after Ivermectin (Heartgard) in dogs

100 reports to the FDA describe excessive thirst in dogs given Ivermectin. That is 0.8% of all reports for this medicine, compared with 1.4% across reports for all dog medicines, so it is reported less often than average with this medicine.

100Reports

39%Marked serious

17%Recovered

14%Died or euthanised

13 daysTypical onset

How soon it started

Same day

11 21%

1–2 days

4 7.5%

3–7 days

7 13%

1–4 weeks

12 23%

Over a month

19 36%

How the animals did

Recovered

14 14%

Recovered with lasting effects

3 3.0%

Still unwell when reported

35 35%

Died

6 6.0%

Euthanised

8 8.0%

Not known

34 34%

Problems reported at the same time

47 47%

35 35%

32 32%

29 29%

24 24%

22 22%

19 19%

14 14%

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 excessive thirst in dogs?: 100 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 13 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).

Excessive thirst with similar medicines

Excessive thirst after Ivermectin + Pyrantel (Heartgard Plus) 404 reports · 0.3% of its reports
Excessive thirst after Milbemycin Oxime + Spinosad (Trifexis) 448 reports · 0.3% of its reports
Excessive thirst after Moxidectin (ProHeart 6) 361 reports · 0.7% of its reports
Excessive thirst after Milbemycin Oxime + Praziquantel (Interceptor Plus) 123 reports · 0.4% of its reports
Excessive thirst after Milbemycin Oxime (Interceptor) 147 reports · 0.5% of its reports
Excessive thirst after Selamectin (Revolution) 160 reports · 0.5% of its reports
Excessive thirst after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 25 reports · 0.3% of its reports

All reported side effects of Ivermectin in dogs · Medicines most reported with excessive thirst