Weight loss after Milbemycin Oxime (Interceptor) in dogs

348 reports to the FDA describe weight loss in dogs given Milbemycin Oxime. That is 1.2% of all reports for this medicine, compared with 1.7% across reports for all dog medicines.

348Reports

24%Marked serious

6.3%Recovered

14%Died or euthanised

80 daysTypical onset

How soon it started

Same day

13 20%

1–2 days

5 7.7%

3–7 days

2 3.1%

1–4 weeks

7 11%

Over a month

38 58%

How the animals did

Recovered

20 5.7%

Recovered with lasting effects

2 0.6%

Still unwell when reported

58 17%

Died

30 8.6%

Euthanised

17 4.9%

Not known

221 64%

Problems reported at the same time

120 34%

97 28%

95 27%

91 26%

78 22%

Didn't work as expected

53 15%

Didn't prevent heartworm

52 15%

Death

45 13%

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 weight loss in dogs?: 348 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 80 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).

Weight loss with similar medicines

Weight loss after Ivermectin + Pyrantel (Heartgard Plus) 889 reports · 0.6% of its reports
Weight loss after Milbemycin Oxime + Spinosad (Trifexis) 1,989 reports · 1.5% of its reports
Weight loss after Moxidectin (ProHeart 6) 858 reports · 1.7% of its reports
Weight loss after Milbemycin Oxime + Praziquantel (Interceptor Plus) 515 reports · 1.6% of its reports
Weight loss after Selamectin (Revolution) 230 reports · 0.8% of its reports
Weight loss after Ivermectin (Heartgard) 200 reports · 1.7% of its reports
Weight loss after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 42 reports · 0.5% of its reports
Weight loss after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 29 reports · 2.5% of its reports

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