Diarrhea after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 2,873 reports of diarrhea in dogs after Milbemycin Oxime. That is 9.7% of all reports for this medicine, compared with 8.4% across reports for all dog medicines.

2,873Reports

6.7%Marked serious

9.0%Recovered

4.8%Died or euthanised

2 daysTypical onset

How soon it started

Same day

141 34%

1–2 days

71 17%

3–7 days

19 4.5%

1–4 weeks

40 9.5%

Over a month

149 35%

How the animals did

Recovered

252 8.8%

Recovered with lasting effects

8 0.3%

Still unwell when reported

200 7.0%

Died

116 4.0%

Euthanised

21 0.7%

Not known

2,276 79%

Problems reported at the same time

1,042 36%

986 34%

508 18%

470 16%

Didn't work as expected

352 12%

Death

135 4.7%

Weight loss

91 3.2%

Liver problems

88 3.1%

Age of the animals

Under 1 year

539

1–3 years

961

4–7 years

650

8–11 years

464

12+ years

183

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 diarrhea in dogs?: 2,873 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).

Diarrhea with similar medicines

Diarrhea after Ivermectin + Pyrantel (Heartgard Plus) 9,076 reports · 6.1% of its reports
Diarrhea after Milbemycin Oxime + Spinosad (Trifexis) 7,183 reports · 5.5% of its reports
Diarrhea after Moxidectin (ProHeart 6) 4,291 reports · 8.5% of its reports
Diarrhea after Milbemycin Oxime + Praziquantel (Interceptor Plus) 2,695 reports · 8.5% of its reports
Diarrhea after Selamectin (Revolution) 1,974 reports · 6.7% of its reports
Diarrhea after Ivermectin (Heartgard) 693 reports · 5.8% of its reports
Diarrhea after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 954 reports · 11% of its reports
Diarrhea after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 125 reports · 11% of its reports

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