Respiratory tract disorder after Diphenhydramine in dogs

The FDA has received 22 reports of respiratory tract disorder in dogs after Diphenhydramine. That is 0.5% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported unusually often with this medicine.

22Reports

82%Marked serious

14%Recovered

59%Died or euthanised

1 daysTypical onset

How soon it started

Same day

8 44%

1–2 days

2 11%

3–7 days

1 5.6%

1–4 weeks

2 11%

Over a month

5 28%

How the animals did

Recovered

3 14%

Still unwell when reported

6 27%

Died

8 36%

Euthanised

5 23%

Problems reported at the same time

13 59%

9 41%

8 36%

7 32%

7 32%

7 32%

Abnormal radiograph finding

7 32%

Allergic reaction

6 27%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Type: medicine.

Questions owners ask

Can Diphenhydramine cause respiratory tract disorder in dogs?: 22 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).

Respiratory tract disorder with similar medicines

Respiratory tract disorder after Melarsomine (Immiticide) 31 reports · 0.1% of its reports

All reported side effects of Diphenhydramine in dogs · Medicines most reported with respiratory tract disorder