Conjunctivitis after Diphenhydramine in dogs

The FDA has received 24 reports of conjunctivitis 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.

24Reports

67%Marked serious

21%Recovered

25%Died or euthanised

2 daysTypical onset

How soon it started

Same day

8 40%

1–2 days

3 15%

3–7 days

1 5.0%

1–4 weeks

4 20%

Over a month

4 20%

How the animals did

Recovered

5 21%

Still unwell when reported

9 38%

Died

3 13%

Euthanised

3 13%

Not known

4 17%

Problems reported at the same time

14 58%

11 46%

9 38%

8 33%

7 29%

7 29%

6 25%

6 25%

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 conjunctivitis in dogs?: 24 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).

Conjunctivitis with similar medicines

Conjunctivitis after Melarsomine (Immiticide) 21 reports · 0.1% of its reports
Conjunctivitis after Cefpodoxime 21 reports · 0.5% of its reports
Conjunctivitis after Florfenicol + Mometasone + Terbinafine 52 reports · 1.5% of its reports
Conjunctivitis after Betamethasone + Florfenicol + Terbinafine 20 reports · 0.8% of its reports
Conjunctivitis after Ketoconazole 20 reports · 0.9% of its reports
Conjunctivitis after Etodolac 20 reports · 1.1% of its reports

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