Hair coat discolouration after Spinosad (Comfortis) in dogs

32 reports to the FDA describe hair coat discolouration in dogs given Spinosad. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

32Reports
6.3%Marked serious
50%Recovered
6.3%Died or euthanised
22 daysTypical onset
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How soon it started

Same day
4 33%
1–2 days
0 0.0%
3–7 days
1 8.3%
1–4 weeks
3 25%
Over a month
4 33%

How the animals did

Recovered
3 9.4%
Recovered with lasting effects
13 41%
Still unwell when reported
2 6.3%
Died
2 6.3%
Not known
12 38%

Problems reported at the same time

Age of the animals

Under 1 year
1
1–3 years
6
4–7 years
7
8–11 years
8
12+ years
2

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 hair coat discolouration in dogs?
32 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).

Hair coat discolouration with similar medicines

All reported side effects of Spinosad in dogs · Medicines most reported with hair coat discolouration