Diarrhea after Fipronil in dogs

123 reports to the FDA describe diarrhea in dogs given Fipronil. That is 8.7% of all reports for this medicine, compared with 8.4% across reports for all dog medicines.

123Reports
41%Marked serious
48%Recovered
5.7%Died or euthanised
22 daysTypical onset
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How soon it started

Same day
13 16%
1–2 days
10 12%
3–7 days
4 4.8%
1–4 weeks
17 20%
Over a month
39 47%

How the animals did

Recovered
52 42%
Recovered with lasting effects
7 5.7%
Still unwell when reported
23 19%
Died
3 2.4%
Euthanised
4 3.3%
Not known
34 28%

Problems reported at the same time

62 50%
39 32%
13 11%
Dehydration
11 8.9%
9 7.3%

Age of the animals

Under 1 year
14
1–3 years
33
4–7 years
30
8–11 years
29
12+ years
16

About this medicine

Fipronil kills fleas and ticks (spot-on).

Questions owners ask

Can Fipronil cause diarrhea in dogs?
123 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 22 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).

Diarrhea with similar medicines

All reported side effects of Fipronil in dogs · Medicines most reported with diarrhea