Lethargy after Ampicillin in cats

The FDA has received 82 reports of lethargy in cats after Ampicillin. That is 27% of all reports for this medicine, compared with 14% across reports for all cat medicines, so it is reported unusually often with this medicine.

82Reports
85%Marked serious
15%Recovered
41%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
22 30%
1–2 days
19 26%
3–7 days
9 12%
1–4 weeks
12 16%
Over a month
11 15%

How the animals did

Recovered
11 13%
Recovered with lasting effects
1 1.2%
Still unwell when reported
26 32%
Died
10 12%
Euthanised
24 29%
Not known
10 12%

Problems reported at the same time

Age of the animals

Under 1 year
14
1–3 years
7
4–7 years
20
8–11 years
24
12+ years
16

About this medicine

Type: medicine.

Questions owners ask

Can Ampicillin cause lethargy in cats?
82 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).

Lethargy with similar medicines

All reported side effects of Ampicillin in cats · Medicines most reported with lethargy