Not drinking after Ivermectin + Pyrantel (Heartgard Plus) in dogs

282 reports to the FDA describe not drinking in dogs given Ivermectin + Pyrantel. That is 0.2% of all reports for this medicine, compared with 0.5% across reports for all dog medicines, so it is reported less often than average with this medicine.

282Reports

55%Marked serious

29%Recovered

8.2%Died or euthanised

1 daysTypical onset

How soon it started

Same day

77 37%

1–2 days

56 27%

3–7 days

15 7.3%

1–4 weeks

20 9.7%

Over a month

38 18%

How the animals did

Recovered

80 28%

Recovered with lasting effects

1 0.4%

Still unwell when reported

46 16%

Died

9 3.2%

Euthanised

14 5.0%

Not known

132 47%

Problems reported at the same time

248 88%

164 58%

131 46%

82 29%

32 11%

32 11%

Digestive tract disorder

24 8.5%

Death

23 8.2%

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 not drinking in dogs?: 282 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 1 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).

Not drinking with similar medicines

Not drinking after Milbemycin Oxime + Spinosad (Trifexis) 962 reports · 0.7% of its reports
Not drinking after Moxidectin (ProHeart 6) 169 reports · 0.3% of its reports
Not drinking after Milbemycin Oxime + Praziquantel (Interceptor Plus) 187 reports · 0.6% of its reports
Not drinking after Milbemycin Oxime (Interceptor) 43 reports · 0.1% of its reports
Not drinking after Selamectin (Revolution) 42 reports · 0.1% of its reports
Not drinking after Ivermectin (Heartgard) 48 reports · 0.4% of its reports
Not drinking after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 41 reports · 0.5% of its reports

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with not drinking