Overdose after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 131 reports of overdose in dogs after Milbemycin Oxime. That is 0.4% of all reports for this medicine, compared with 1.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

131Reports

42%Marked serious

24%Recovered

3.8%Died or euthanised

9 daysTypical onset

How soon it started

Same day

16 40%

1–2 days

3 7.5%

3–7 days

1 2.5%

1–4 weeks

5 13%

Over a month

15 38%

How the animals did

Recovered

31 24%

Recovered with lasting effects

1 0.8%

Still unwell when reported

44 34%

Died

3 2.3%

Euthanised

2 1.5%

Not known

50 38%

Problems reported at the same time

Didn't prevent heartworm

44 34%

23 18%

21 16%

20 15%

16 12%

Didn't work as expected

14 11%

Tremors

12 9.2%

Diarrhea

11 8.4%

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 overdose in dogs?: 131 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 9 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).

Overdose with similar medicines

Overdose after Ivermectin + Pyrantel (Heartgard Plus) 1,647 reports · 1.1% of its reports
Overdose after Milbemycin Oxime + Spinosad (Trifexis) 2,052 reports · 1.6% of its reports
Overdose after Moxidectin (ProHeart 6) 366 reports · 0.7% of its reports
Overdose after Milbemycin Oxime + Praziquantel (Interceptor Plus) 266 reports · 0.8% of its reports
Overdose after Selamectin (Revolution) 160 reports · 0.5% of its reports
Overdose after Ivermectin (Heartgard) 134 reports · 1.1% of its reports
Overdose after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 185 reports · 2.2% of its reports
Overdose after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 31 reports · 2.7% of its reports

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