Ear infection after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 36 reports of ear infection in dogs after Milbemycin Oxime. That is 0.1% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

36Reports

28%Marked serious

19%Recovered

5.6%Died or euthanised

118 daysTypical onset

How soon it started

Same day

1 10%

1–2 days

1 10%

3–7 days

1 10%

1–4 weeks

1 10%

Over a month

6 60%

How the animals did

Recovered

6 17%

Recovered with lasting effects

1 2.8%

Still unwell when reported

14 39%

Died

1 2.8%

Euthanised

1 2.8%

Not known

13 36%

Problems reported at the same time

Didn't work as expected

8 22%

Vomiting

7 19%

Didn't prevent heartworm

6 17%

Itching

5 14%

Diarrhea

5 14%

Skin rash or irritation

4 11%

Didn't stop worms

3 8.3%

Skin redness

3 8.3%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly).

Products with this ingredient include Interceptor. 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 Milbemycin Oxime cause ear infection in dogs?: 36 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 118 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).

Ear infection with similar medicines

Ear infection after Ivermectin + Pyrantel (Heartgard Plus) 116 reports · 0.1% of its reports
Ear infection after Milbemycin Oxime + Spinosad (Trifexis) 524 reports · 0.4% of its reports
Ear infection after Moxidectin (ProHeart 6) 34 reports · 0.1% of its reports
Ear infection after Milbemycin Oxime + Praziquantel (Interceptor Plus) 206 reports · 0.7% of its reports
Ear infection after Ivermectin (Heartgard) 36 reports · 0.3% of its reports

All reported side effects of Milbemycin Oxime in dogs · Medicines most reported with ear infection