Tremors after Milbemycin Oxime (Interceptor) in dogs

729 reports to the FDA describe tremors in dogs given Milbemycin Oxime. That is 2.4% of all reports for this medicine, compared with 3.4% across reports for all dog medicines.

729Reports

18%Marked serious

17%Recovered

4.8%Died or euthanised

1 daysTypical onset

How soon it started

Same day

81 40%

1–2 days

41 20%

3–7 days

14 6.9%

1–4 weeks

23 11%

Over a month

43 21%

How the animals did

Recovered

114 16%

Recovered with lasting effects

7 1.0%

Still unwell when reported

92 13%

Died

26 3.6%

Euthanised

9 1.2%

Not known

481 66%

Problems reported at the same time

237 33%

187 26%

152 21%

118 16%

111 15%

93 13%

64 8.8%

55 7.5%

Age of the animals

Under 1 year

166

1–3 years

227

4–7 years

148

8–11 years

113

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 tremors in dogs?: 729 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 1 day 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).

Tremors with similar medicines

Tremors after Ivermectin + Pyrantel (Heartgard Plus) 2,169 reports · 1.5% of its reports
Tremors after Milbemycin Oxime + Spinosad (Trifexis) 5,684 reports · 4.4% of its reports
Tremors after Moxidectin (ProHeart 6) 1,208 reports · 2.4% of its reports
Tremors after Milbemycin Oxime + Praziquantel (Interceptor Plus) 766 reports · 2.4% of its reports
Tremors after Selamectin (Revolution) 984 reports · 3.3% of its reports
Tremors after Ivermectin (Heartgard) 959 reports · 8.0% of its reports
Tremors after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 245 reports · 2.9% of its reports
Tremors after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 56 reports · 4.8% of its reports
Tremors after Ivermectin + Praziquantel 61 reports · 30% of its reports
Tremors after Moxidectin + Praziquantel 27 reports · 36% of its reports

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