Pacing after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 37 reports of pacing in dogs after Milbemycin Oxime. That is 0.1% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

37Reports

24%Marked serious

19%Recovered

8.1%Died or euthanised

2 daysTypical onset

How soon it started

Same day

4 27%

1–2 days

4 27%

3–7 days

0 0.0%

1–4 weeks

1 6.7%

Over a month

6 40%

How the animals did

Recovered

7 19%

Still unwell when reported

6 16%

Died

1 2.7%

Euthanised

2 5.4%

Not known

21 57%

Problems reported at the same time

Breathing problems

16 43%

Restlessness or agitation

14 38%

11 30%

7 19%

7 19%

7 19%

7 19%

6 16%

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 pacing in dogs?: 37 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 2 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).

Pacing with similar medicines

Pacing after Ivermectin + Pyrantel (Heartgard Plus) 205 reports · 0.1% of its reports
Pacing after Milbemycin Oxime + Spinosad (Trifexis) 139 reports · 0.1% of its reports
Pacing after Moxidectin (ProHeart 6) 119 reports · 0.2% of its reports
Pacing after Milbemycin Oxime + Praziquantel (Interceptor Plus) 54 reports · 0.2% of its reports
Pacing after Selamectin (Revolution) 112 reports · 0.4% of its reports
Pacing after Ivermectin (Heartgard) 27 reports · 0.2% of its reports

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