Tremors after Milbemycin Oxime + Praziquantel (Interceptor Plus) in dogs

The FDA has received 766 reports of tremors in dogs after Milbemycin Oxime + Praziquantel. That is 2.4% of all reports for this medicine, compared with 3.4% across reports for all dog medicines.

766Reports

33%Marked serious

42%Recovered

2.3%Died or euthanised

2 daysTypical onset

How soon it started

Same day

231 38%

1–2 days

94 15%

3–7 days

37 6.0%

1–4 weeks

49 8.0%

Over a month

205 33%

How the animals did

Recovered

317 41%

Recovered with lasting effects

2 0.3%

Still unwell when reported

259 34%

Died

6 0.8%

Euthanised

12 1.6%

Not known

170 22%

Problems reported at the same time

236 31%

181 24%

142 19%

135 18%

134 17%

99 13%

89 12%

82 11%

Age of the animals

Under 1 year

137

1–3 years

223

4–7 years

181

8–11 years

128

12+ years

About this medicine

Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly). Praziquantel treats tapeworms.

Products with this combination include Interceptor Plus. 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 + Praziquantel cause tremors in dogs?: 766 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).

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 (Interceptor) 729 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 + Praziquantel in dogs · Medicines most reported with tremors