Seizures after Diphenhydramine in dogs

192 reports to the FDA describe seizures in dogs given Diphenhydramine. That is 4.1% of all reports for this medicine, compared with 4.4% across reports for all dog medicines.

192Reports
92%Marked serious
25%Recovered
24%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
85 54%
1–2 days
21 13%
3–7 days
9 5.8%
1–4 weeks
15 9.6%
Over a month
26 17%

How the animals did

Recovered
44 23%
Recovered with lasting effects
4 2.1%
Still unwell when reported
66 34%
Died
27 14%
Euthanised
20 10%
Not known
31 16%

Problems reported at the same time

Age of the animals

Under 1 year
19
1–3 years
53
4–7 years
55
8–11 years
35
12+ years
30

About this medicine

Type: medicine.

Questions owners ask

Can Diphenhydramine cause seizures in dogs?
192 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 the same 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).

Seizures with similar medicines

All reported side effects of Diphenhydramine in dogs · Medicines most reported with seizures