Urinary tract infection after Milbemycin Oxime (Interceptor) in dogs

The FDA has received 50 reports of urinary tract infection in dogs after Milbemycin Oxime. That is 0.2% of all reports for this medicine, compared with 0.5% across reports for all dog medicines, so it is reported less often than average with this medicine.

50Reports

30%Marked serious

16%Recovered

4.0%Died or euthanised

72 daysTypical onset

How soon it started

Same day

0 0.0%

1–2 days

2 15%

3–7 days

0 0.0%

1–4 weeks

2 15%

Over a month

9 69%

How the animals did

Recovered

6 12%

Recovered with lasting effects

2 4.0%

Still unwell when reported

15 30%

Died

1 2.0%

Euthanised

1 2.0%

Not known

25 50%

Problems reported at the same time

Vomiting

16 32%

Lethargy

11 22%

Loss of appetite

9 18%

Crystalluria

6 12%

Didn't work as expected

6 12%

Didn't stop worms

6 12%

Diarrhea

5 10%

Excessive thirst

5 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).

Products with this ingredient include Interceptor. 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 cause urinary tract infection in dogs?: 50 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 72 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 + Praziquantel (Interceptor Plus) 147 reports · 0.5% 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 in dogs · Medicines most reported with urinary tract infection