Urinary tract infection after Milbemycin Oxime + Praziquantel (Interceptor Plus) in dogs

The FDA has received 147 reports of urinary tract infection in dogs after Milbemycin Oxime + Praziquantel. That is 0.5% of all reports for this medicine, compared with 0.5% across reports for all dog medicines.

147Reports

30%Marked serious

15%Recovered

4.1%Died or euthanised

33 daysTypical onset

How soon it started

Same day

4 5.7%

1–2 days

5 7.1%

3–7 days

5 7.1%

1–4 weeks

17 24%

Over a month

39 56%

How the animals did

Recovered

18 12%

Recovered with lasting effects

4 2.7%

Still unwell when reported

39 27%

Died

2 1.4%

Euthanised

4 2.7%

Not known

80 54%

Problems reported at the same time

Didn't stop worms

33 22%

Vomiting

28 19%

Didn't work as expected

26 18%

Didn't prevent heartworm

22 15%

18 12%

17 12%

15 10%

15 10%

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 urinary tract infection in dogs?: 147 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).

Urinary tract infection with similar medicines

Urinary tract infection after Ivermectin + Pyrantel (Heartgard Plus) 135 reports · 0.1% of its reports
Urinary tract infection after Milbemycin Oxime + Spinosad (Trifexis) 337 reports · 0.3% of its reports
Urinary tract infection after Moxidectin (ProHeart 6) 111 reports · 0.2% of its reports
Urinary tract infection after Milbemycin Oxime (Interceptor) 50 reports · 0.2% of its reports
Urinary tract infection after Selamectin (Revolution) 34 reports · 0.1% of its reports
Urinary tract infection after Ivermectin (Heartgard) 52 reports · 0.4% of its reports

All reported side effects of Milbemycin Oxime + Praziquantel in dogs · Medicines most reported with urinary tract infection