Fentanyl side effects in cats

83 reports sent to the FDA between 1998 and 2026 involve Fentanyl in cats. The most reported problems were loss of appetite, fever, hypotension. 63% were marked serious.

83Reports
63%Marked serious
7.2%Only medicine involved
22%Recovered
30%Died or euthanised
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About this medicine

Type: medicine.

Most reported side effects

Fever
15 18%
Hypotension
14 17%
Lethargy
12 14%
Hyperglycaemia
12 14%
Swelling
11 13%
Blood problems
10 12%
Liver problems
10 12%
Kidney problems
10 12%
Breathing problems
10 12%
Weight loss
9 11%
Behaviour change
9 11%
Dehydration
8 9.6%
Drooling
7 8.4%
Hypothermia
7 8.4%

Share = percentage of this medicine's reports that mention the problem. One report can list several problems.

Reports that it didn't work

Some reports are about the medicine not working (for example a cat still getting fleas or heartworm), not about a side effect.

Didn't work as expected
9 11%

How soon problems started

Same day
31 48%
1–2 days
11 17%
3–7 days
7 11%
1–4 weeks
10 15%
Over a month
6 9.2%

Time from the first dose to the first sign, where both dates were reported (65 reports).

How the animals did

Recovered
17 20%
Recovered with lasting effects
1 1.2%
Still unwell when reported
24 29%
Died
11 13%
Euthanised
14 17%
Not known
16 19%

Breeds named most often

Popular breeds appear more often because there are more of them.

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