Blood in faeces after Milbemycin Oxime + Praziquantel (Interceptor Plus) in dogs

The FDA has received 84 reports of blood in faeces in dogs after Milbemycin Oxime + Praziquantel. That is 0.3% of all reports for this medicine, compared with 0.2% across reports for all dog medicines.

84Reports

29%Marked serious

14%Recovered

6.0%Died or euthanised

29 daysTypical onset

How soon it started

Same day

8 13%

1–2 days

10 16%

3–7 days

4 6.5%

1–4 weeks

11 18%

Over a month

29 47%

How the animals did

Recovered

12 14%

Still unwell when reported

27 32%

Died

2 2.4%

Euthanised

3 3.6%

Not known

40 48%

Problems reported at the same time

36 43%

30 36%

29 35%

21 25%

19 23%

16 19%

9 11%

8 9.5%

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 blood in faeces in dogs?: 84 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 29 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).

Blood in faeces with similar medicines

Blood in faeces after Ivermectin + Pyrantel (Heartgard Plus) 355 reports · 0.2% of its reports
Blood in faeces after Milbemycin Oxime + Spinosad (Trifexis) 215 reports · 0.2% of its reports
Blood in faeces after Moxidectin (ProHeart 6) 133 reports · 0.3% of its reports
Blood in faeces after Milbemycin Oxime (Interceptor) 26 reports · 0.1% of its reports
Blood in faeces after Selamectin (Revolution) 31 reports · 0.1% of its reports
Blood in faeces after Ivermectin (Heartgard) 32 reports · 0.3% of its reports
Blood in faeces after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 26 reports · 0.3% of its reports

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