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

The FDA has received 133 reports of neutrophilia in dogs after Milbemycin Oxime + Praziquantel. That is 0.4% of all reports for this medicine, compared with 0.6% across reports for all dog medicines.

133Reports

71%Marked serious

12%Recovered

17%Died or euthanised

33 daysTypical onset

How soon it started

Same day

14 16%

1–2 days

15 18%

3–7 days

3 3.5%

1–4 weeks

9 11%

Over a month

44 52%

How the animals did

Recovered

15 11%

Recovered with lasting effects

1 0.8%

Still unwell when reported

54 41%

Died

11 8.3%

Euthanised

11 8.3%

Not known

41 31%

Problems reported at the same time

66 50%

61 46%

56 42%

48 36%

47 35%

35 26%

34 26%

31 23%

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 neutrophilia in dogs?: 133 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 33 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).

Neutrophilia with similar medicines

Neutrophilia after Ivermectin + Pyrantel (Heartgard Plus) 327 reports · 0.2% of its reports
Neutrophilia after Milbemycin Oxime + Spinosad (Trifexis) 440 reports · 0.3% of its reports
Neutrophilia after Moxidectin (ProHeart 6) 429 reports · 0.8% of its reports
Neutrophilia after Milbemycin Oxime (Interceptor) 56 reports · 0.2% of its reports
Neutrophilia after Selamectin (Revolution) 75 reports · 0.3% of its reports
Neutrophilia after Ivermectin (Heartgard) 69 reports · 0.6% of its reports
Neutrophilia after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 20 reports · 0.2% of its reports

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