Leucocytosis after Butorphanol in cats

The FDA has received 41 reports of leucocytosis in cats after Butorphanol. That is 1.8% of all reports for this medicine, compared with 0.9% across reports for all cat medicines, so it is reported unusually often with this medicine.

41Reports

59%Marked serious

15%Recovered

32%Died or euthanised

2 daysTypical onset

How soon it started

Same day

10 33%

1–2 days

7 23%

3–7 days

8 27%

1–4 weeks

3 10%

Over a month

2 6.7%

How the animals did

Recovered

5 12%

Recovered with lasting effects

1 2.4%

Still unwell when reported

12 29%

Died

6 15%

Euthanised

7 17%

Not known

10 24%

Problems reported at the same time

21 51%

17 41%

16 39%

14 34%

14 34%

13 32%

13 32%

12 29%

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 Butorphanol cause leucocytosis in cats?: 41 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).

Leucocytosis with similar medicines

Leucocytosis after Methylprednisolone 57 reports · 3.5% of its reports
Leucocytosis after Marbofloxacin 26 reports · 4.6% of its reports
Leucocytosis after Ampicillin 21 reports · 7.0% of its reports

All reported side effects of Butorphanol in cats · Medicines most reported with leucocytosis