Drug dose omission after Ivermectin (Heartgard) in dogs

72 reports to the FDA describe drug dose omission in dogs given Ivermectin. That is 0.6% of all reports for this medicine, compared with 0.4% across reports for all dog medicines, so it is reported unusually often with this medicine.

72Reports

18%Marked serious

5.6%Recovered

0.0%Died or euthanised

256 daysTypical onset

How soon it started

Same day

1 9.1%

1–2 days

0 0.0%

3–7 days

0 0.0%

1–4 weeks

0 0.0%

Over a month

10 91%

How the animals did

Recovered

3 4.2%

Recovered with lasting effects

1 1.4%

Still unwell when reported

17 24%

Not known

51 71%

Problems reported at the same time

Didn't prevent heartworm

52 72%

Didn't stop fleas

14 19%

Didn't work as expected

5 6.9%

5 6.9%

3 4.2%

3 4.2%

3 4.2%

3 4.2%

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).

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 drug dose omission in dogs?: 72 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 256 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).

Drug dose omission with similar medicines

Drug dose omission after Ivermectin + Pyrantel (Heartgard Plus) 503 reports · 0.3% of its reports
Drug dose omission after Milbemycin Oxime + Spinosad (Trifexis) 1,201 reports · 0.9% of its reports
Drug dose omission after Moxidectin (ProHeart 6) 53 reports · 0.1% of its reports
Drug dose omission after Milbemycin Oxime + Praziquantel (Interceptor Plus) 399 reports · 1.3% of its reports
Drug dose omission after Milbemycin Oxime (Interceptor) 109 reports · 0.4% of its reports
Drug dose omission after Selamectin (Revolution) 87 reports · 0.3% of its reports
Drug dose omission after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 87 reports · 1.0% of its reports

All reported side effects of Ivermectin in dogs · Medicines most reported with drug dose omission