Restlessness or agitation after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 250 reports of restlessness or agitation in dogs after Milbemycin Oxime. That is 0.8% of all reports for this medicine, compared with 1.6% across reports for all dog medicines, so it is reported less often than average with this medicine.

250Reports

18%Marked serious

19%Recovered

3.2%Died or euthanised

3 daysTypical onset

How soon it started

Same day

23 37%

1–2 days

8 13%

3–7 days

3 4.8%

1–4 weeks

3 4.8%

Over a month

25 40%

How the animals did

Recovered

47 19%

Still unwell when reported

24 9.6%

Died

6 2.4%

Euthanised

2 0.8%

Not known

171 68%

Problems reported at the same time

49 20%

47 19%

41 16%

38 15%

37 15%

34 14%

32 13%

25 10%

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 restlessness or agitation in dogs?: 250 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 3 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).

Restlessness or agitation with similar medicines

Restlessness or agitation after Ivermectin + Pyrantel (Heartgard Plus) 1,021 reports · 0.7% of its reports
Restlessness or agitation after Milbemycin Oxime + Spinosad (Trifexis) 1,101 reports · 0.8% of its reports
Restlessness or agitation after Moxidectin (ProHeart 6) 508 reports · 1.0% of its reports
Restlessness or agitation after Milbemycin Oxime + Praziquantel (Interceptor Plus) 222 reports · 0.7% of its reports
Restlessness or agitation after Selamectin (Revolution) 561 reports · 1.9% of its reports
Restlessness or agitation after Ivermectin (Heartgard) 213 reports · 1.8% of its reports
Restlessness or agitation after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 82 reports · 1.0% of its reports
Restlessness or agitation after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 20 reports · 1.7% of its reports

All reported side effects of Milbemycin Oxime in dogs · Medicines most reported with restlessness or agitation