Hair loss after Ivermectin (Heartgard) in dogs

104 reports to the FDA describe hair loss in dogs given Ivermectin. That is 0.9% of all reports for this medicine, compared with 1.0% across reports for all dog medicines.

104Reports

33%Marked serious

33%Recovered

3.8%Died or euthanised

39 daysTypical onset

How soon it started

Same day

11 18%

1–2 days

2 3.3%

3–7 days

5 8.2%

1–4 weeks

12 20%

Over a month

31 51%

How the animals did

Recovered

14 13%

Recovered with lasting effects

20 19%

Still unwell when reported

30 29%

Died

1 1.0%

Euthanised

3 2.9%

Not known

36 35%

Problems reported at the same time

Itching

40 38%

Skin rash or irritation

18 17%

14 13%

13 13%

12 12%

10 9.6%

9 8.7%

Reddening of the skin

9 8.7%

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 hair loss in dogs?: 104 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 39 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).

Hair loss with similar medicines

Hair loss after Ivermectin + Pyrantel (Heartgard Plus) 539 reports · 0.4% of its reports
Hair loss after Milbemycin Oxime + Spinosad (Trifexis) 1,029 reports · 0.8% of its reports
Hair loss after Moxidectin (ProHeart 6) 325 reports · 0.6% of its reports
Hair loss after Milbemycin Oxime + Praziquantel (Interceptor Plus) 158 reports · 0.5% of its reports
Hair loss after Milbemycin Oxime (Interceptor) 132 reports · 0.4% of its reports
Hair loss after Selamectin (Revolution) 1,036 reports · 3.5% of its reports
Hair loss after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 20 reports · 0.2% of its reports

All reported side effects of Ivermectin in dogs · Medicines most reported with hair loss