Excessive thirst after Ivermectin + Pyrantel (Heartgard Plus) in dogs

404 reports to the FDA describe excessive thirst in dogs given Ivermectin + Pyrantel. That is 0.3% 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.

404Reports

50%Marked serious

22%Recovered

9.2%Died or euthanised

7 daysTypical onset

How soon it started

Same day

58 31%

1–2 days

24 13%

3–7 days

22 12%

1–4 weeks

25 13%

Over a month

61 32%

How the animals did

Recovered

81 20%

Recovered with lasting effects

9 2.2%

Still unwell when reported

59 15%

Died

14 3.5%

Euthanised

23 5.7%

Not known

218 54%

Problems reported at the same time

143 35%

130 32%

111 27%

96 24%

63 16%

62 15%

52 13%

39 9.7%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

116

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 excessive thirst in dogs?: 404 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 7 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 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 (Heartgard) 100 reports · 0.8% of its reports
Excessive thirst after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 25 reports · 0.3% of its reports

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