Swelling after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 257 reports of swelling in dogs after Milbemycin Oxime. That is 0.9% of all reports for this medicine, compared with 2.8% across reports for all dog medicines, so it is reported less often than average with this medicine.

257Reports

18%Marked serious

17%Recovered

12%Died or euthanised

19 daysTypical onset

How soon it started

Same day

21 26%

1–2 days

11 14%

3–7 days

2 2.5%

1–4 weeks

11 14%

Over a month

36 44%

How the animals did

Recovered

43 17%

Still unwell when reported

29 11%

Died

28 11%

Euthanised

2 0.8%

Not known

155 60%

Problems reported at the same time

90 35%

59 23%

49 19%

48 19%

35 14%

33 13%

32 12%

23 8.9%

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 swelling in dogs?: 257 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 19 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).

Swelling with similar medicines

Swelling after Ivermectin + Pyrantel (Heartgard Plus) 839 reports · 0.6% of its reports
Swelling after Milbemycin Oxime + Spinosad (Trifexis) 959 reports · 0.7% of its reports
Swelling after Moxidectin (ProHeart 6) 7,913 reports · 16% of its reports
Swelling after Milbemycin Oxime + Praziquantel (Interceptor Plus) 371 reports · 1.2% of its reports
Swelling after Selamectin (Revolution) 410 reports · 1.4% of its reports
Swelling after Ivermectin (Heartgard) 204 reports · 1.7% of its reports
Swelling after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 66 reports · 0.8% of its reports
Swelling after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 22 reports · 1.9% of its reports

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