Walking difficulty after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 34 reports of walking difficulty in dogs after Milbemycin Oxime. That is 0.1% of all reports for this medicine, compared with 0.4% across reports for all dog medicines, so it is reported less often than average with this medicine.

34Reports

71%Marked serious

29%Recovered

24%Died or euthanised

15 daysTypical onset

How soon it started

Same day

6 27%

1–2 days

5 23%

3–7 days

0 0.0%

1–4 weeks

2 9.1%

Over a month

9 41%

How the animals did

Recovered

10 29%

Still unwell when reported

13 38%

Died

3 8.8%

Euthanised

5 15%

Not known

3 8.8%

Problems reported at the same time

14 41%

14 41%

11 32%

10 29%

10 29%

8 24%

6 18%

5 15%

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 walking difficulty in dogs?: 34 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 15 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).

Walking difficulty with similar medicines

Walking difficulty after Ivermectin + Pyrantel (Heartgard Plus) 281 reports · 0.2% of its reports
Walking difficulty after Milbemycin Oxime + Spinosad (Trifexis) 580 reports · 0.4% of its reports
Walking difficulty after Moxidectin (ProHeart 6) 147 reports · 0.3% of its reports
Walking difficulty after Milbemycin Oxime + Praziquantel (Interceptor Plus) 113 reports · 0.4% of its reports
Walking difficulty after Selamectin (Revolution) 51 reports · 0.2% of its reports
Walking difficulty after Ivermectin (Heartgard) 70 reports · 0.6% of its reports
Walking difficulty after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 24 reports · 0.3% of its reports

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