Lethargy after Vitamin B12 in dogs

119 reports to the FDA describe lethargy in dogs given Vitamin B12. That is 31% of all reports for this medicine, compared with 11% across reports for all dog medicines, so it is reported unusually often with this medicine.

119Reports
79%Marked serious
13%Recovered
35%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
21 21%
1–2 days
26 26%
3–7 days
14 14%
1–4 weeks
17 17%
Over a month
23 23%

How the animals did

Recovered
14 12%
Recovered with lasting effects
2 1.7%
Still unwell when reported
52 44%
Died
24 20%
Euthanised
18 15%
Not known
9 7.6%

Problems reported at the same time

Age of the animals

Under 1 year
19
1–3 years
18
4–7 years
22
8–11 years
35
12+ years
25

About this medicine

Type: medicine.

Questions owners ask

Can Vitamin B12 cause lethargy in dogs?
119 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 3 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 Vitamin B12 in dogs · Medicines most reported with lethargy