Loss of appetite after Diphenhydramine in cats

The FDA has received 124 reports of loss of appetite in cats after Diphenhydramine. That is 34% of all reports for this medicine, compared with 14% across reports for all cat medicines, so it is reported unusually often with this medicine.

124Reports
67%Marked serious
33%Recovered
20%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
69 59%
1–2 days
22 19%
3–7 days
9 7.8%
1–4 weeks
11 9.5%
Over a month
5 4.3%

How the animals did

Recovered
41 33%
Still unwell when reported
43 35%
Died
10 8.1%
Euthanised
15 12%
Not known
15 12%

Problems reported at the same time

Age of the animals

Under 1 year
17
1–3 years
36
4–7 years
35
8–11 years
17
12+ years
19

About this medicine

Type: medicine.

Questions owners ask

Can Diphenhydramine cause loss of appetite in cats?
124 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).

Loss of appetite with similar medicines

All reported side effects of Diphenhydramine in cats · Medicines most reported with loss of appetite