Application site reaction after Diphenhydramine in dogs

The FDA has received 47 reports of application site reaction in dogs after Diphenhydramine. That is 1.0% of all reports for this medicine, compared with 0.4% across reports for all dog medicines, so it is reported unusually often with this medicine.

47Reports

57%Marked serious

30%Recovered

0.0%Died or euthanised

2 daysTypical onset

How soon it started

Same day

9 23%

1–2 days

12 30%

3–7 days

8 20%

1–4 weeks

6 15%

Over a month

5 13%

How the animals did

Recovered

14 30%

Still unwell when reported

6 13%

Not known

27 57%

Problems reported at the same time

Skin redness

22 47%

Injection site reaction

21 45%

Swelling

19 40%

Didn't work as expected

16 34%

15 32%

12 26%

11 23%

10 21%

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 application site reaction in dogs?: 47 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 2 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).

Application site reaction with similar medicines

Application site reaction after Melarsomine (Immiticide) 22 reports · 0.1% of its reports
Application site reaction after Butorphanol 28 reports · 0.6% of its reports
Application site reaction after Cefpodoxime 47 reports · 1.2% of its reports
Application site reaction after Tramadol 23 reports · 0.6% of its reports
Application site reaction after Florfenicol + Mometasone + Terbinafine 104 reports · 2.9% of its reports
Application site reaction after Isoflurane 20 reports · 0.7% of its reports
Application site reaction after Cephalexin 21 reports · 0.8% of its reports
Application site reaction after Famotidine 25 reports · 0.9% of its reports
Application site reaction after Clotrimazole + Gentamicin + Mometasone 42 reports · 1.6% of its reports
Application site reaction after Betamethasone + Florfenicol + Terbinafine 79 reports · 3.2% of its reports

All reported side effects of Diphenhydramine in dogs · Medicines most reported with application site reaction