Neutrophilia after Vitamin B12 in cats

The FDA has received 20 reports of neutrophilia in cats after Vitamin B12. That is 5.2% of all reports for this medicine, compared with 0.7% across reports for all cat medicines, so it is reported unusually often with this medicine.

20Reports

75%Marked serious

10%Recovered

10%Died or euthanised

10 daysTypical onset

How soon it started

Same day

2 11%

1–2 days

4 22%

3–7 days

1 5.6%

1–4 weeks

6 33%

Over a month

5 28%

How the animals did

Recovered

1 5.0%

Recovered with lasting effects

1 5.0%

Still unwell when reported

9 45%

Euthanised

2 10%

Not known

7 35%

Problems reported at the same time

12 60%

9 45%

8 40%

8 40%

Leucocytosis

7 35%

Kidney problems

7 35%

Weakness

6 30%

Decreased haematocrit

6 30%

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 Vitamin B12 cause neutrophilia in cats?: 20 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 10 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).

Neutrophilia with similar medicines

Neutrophilia after Ketamine 23 reports · 0.7% of its reports
Neutrophilia after Butorphanol 29 reports · 1.3% of its reports
Neutrophilia after Isoflurane 28 reports · 1.4% of its reports
Neutrophilia after Methylprednisolone 42 reports · 2.6% of its reports

All reported side effects of Vitamin B12 in cats · Medicines most reported with neutrophilia