Death after Diphenhydramine in dogs

455 reports to the FDA describe death in dogs given Diphenhydramine. That is 9.6% of all reports for this medicine, compared with 5.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

455Reports
99%Marked serious
0.0%Recovered
100%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
191 49%
1–2 days
50 13%
3–7 days
32 8.2%
1–4 weeks
49 13%
Over a month
69 18%

How the animals did

Died
231 51%
Euthanised
224 49%

Problems reported at the same time

Age of the animals

Under 1 year
40
1–3 years
68
4–7 years
107
8–11 years
141
12+ years
95

About this medicine

Type: medicine.

Questions owners ask

Can Diphenhydramine cause death in dogs?
455 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).

Death with similar medicines

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