Shock after Diphenhydramine in dogs

The FDA has received 20 reports of shock in dogs after Diphenhydramine. That is 0.4% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

20Reports

100%Marked serious

20%Recovered

45%Died or euthanised

Same dayTypical onset

How soon it started

Same day

13 68%

1–2 days

1 5.3%

3–7 days

2 11%

1–4 weeks

1 5.3%

Over a month

2 11%

How the animals did

Recovered

4 20%

Still unwell when reported

6 30%

Died

3 15%

Euthanised

6 30%

Not known

1 5.0%

Problems reported at the same time

15 75%

11 55%

9 45%

8 40%

8 40%

8 40%

7 35%

6 30%

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 shock in dogs?: 20 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).

Shock with similar medicines

Shock after Melarsomine (Immiticide) 183 reports · 0.8% of its reports
Shock after Butorphanol 25 reports · 0.6% of its reports
Shock after Propofol 25 reports · 0.8% of its reports
Shock after Isoflurane 21 reports · 0.8% of its reports
Shock after Triamcinolone 30 reports · 3.4% of its reports

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