Musculoskeletal disorder after Ivermectin (Heartgard) in dogs

53 reports to the FDA describe musculoskeletal disorder in dogs given Ivermectin. That is 0.4% of all reports for this medicine, compared with 0.3% across reports for all dog medicines.

53Reports

60%Marked serious

26%Recovered

11%Died or euthanised

34 daysTypical onset

How soon it started

Same day

5 16%

1–2 days

3 9.4%

3–7 days

4 13%

1–4 weeks

4 13%

Over a month

16 50%

How the animals did

Recovered

10 19%

Recovered with lasting effects

4 7.5%

Still unwell when reported

20 38%

Died

2 3.8%

Euthanised

4 7.5%

Not known

13 25%

Problems reported at the same time

17 32%

12 23%

11 21%

8 15%

7 13%

7 13%

7 13%

6 11%

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 musculoskeletal disorder in dogs?: 53 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 34 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).

Musculoskeletal disorder with similar medicines

Musculoskeletal disorder after Ivermectin + Pyrantel (Heartgard Plus) 197 reports · 0.1% of its reports
Musculoskeletal disorder after Milbemycin Oxime + Spinosad (Trifexis) 352 reports · 0.3% of its reports
Musculoskeletal disorder after Moxidectin (ProHeart 6) 127 reports · 0.3% of its reports
Musculoskeletal disorder after Milbemycin Oxime + Praziquantel (Interceptor Plus) 92 reports · 0.3% of its reports
Musculoskeletal disorder after Milbemycin Oxime (Interceptor) 60 reports · 0.2% of its reports
Musculoskeletal disorder after Selamectin (Revolution) 61 reports · 0.2% of its reports

All reported side effects of Ivermectin in dogs · Medicines most reported with musculoskeletal disorder