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

The FDA has received 153 reports of collapse in dogs after Milbemycin Oxime + Praziquantel. That is 0.5% of all reports for this medicine, compared with 0.9% across reports for all dog medicines, so it is reported less often than average with this medicine.

153Reports

91%Marked serious

29%Recovered

27%Died or euthanised

3 daysTypical onset

How soon it started

Same day

31 31%

1–2 days

17 17%

3–7 days

6 6.0%

1–4 weeks

11 11%

Over a month

35 35%

How the animals did

Recovered

43 28%

Recovered with lasting effects

1 0.7%

Still unwell when reported

36 24%

Died

26 17%

Euthanised

15 9.8%

Not known

32 21%

Problems reported at the same time

41 27%

39 25%

32 21%

31 20%

28 18%

25 16%

25 16%

23 15%

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). 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 collapse in dogs?: 153 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 3 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).

Collapse with similar medicines

Collapse after Ivermectin + Pyrantel (Heartgard Plus) 432 reports · 0.3% of its reports
Collapse after Milbemycin Oxime + Spinosad (Trifexis) 471 reports · 0.4% of its reports
Collapse after Moxidectin (ProHeart 6) 1,511 reports · 3.0% of its reports
Collapse after Milbemycin Oxime (Interceptor) 163 reports · 0.5% of its reports
Collapse after Selamectin (Revolution) 115 reports · 0.4% of its reports
Collapse after Ivermectin (Heartgard) 109 reports · 0.9% of its reports
Collapse after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 60 reports · 0.7% of its reports

All reported side effects of Milbemycin Oxime + Praziquantel in dogs · Medicines most reported with collapse