Dehydration after Spinosad (Comfortis) in dogs

The FDA has received 281 reports of dehydration in dogs after Spinosad. That is 0.5% of all reports for this medicine, compared with 0.7% across reports for all dog medicines.

281Reports
52%Marked serious
32%Recovered
20%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
56 37%
1–2 days
33 22%
3–7 days
9 5.9%
1–4 weeks
8 5.2%
Over a month
47 31%

How the animals did

Recovered
58 21%
Recovered with lasting effects
33 12%
Still unwell when reported
23 8.2%
Died
38 14%
Euthanised
18 6.4%
Not known
111 40%

Problems reported at the same time

Age of the animals

Under 1 year
27
1–3 years
85
4–7 years
82
8–11 years
55
12+ years
27

About this medicine

Spinosad kills fleas; monthly chewable.

Products with this ingredient include Comfortis. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Questions owners ask

Can Spinosad cause dehydration in dogs?
281 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 1 day 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).

Dehydration with similar medicines

All reported side effects of Spinosad in dogs · Medicines most reported with dehydration