Drug profile

The FDA adverse-event record for B12

34 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference B12. Species, reactions, and outcomes follow.

#1345 of 2,679
by report volume (all drugs)
34
adverse-event reports
11.8%
death-coded share
Cat
most-reported species
Verify with FDA CVM →

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, B12 ranks #1344 of 2679 by total reports (34). Death-coded-share rank requires at least 50 reports. National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#1344
This drug, reports of 2679

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. B12 has 34 reports now versus 34 in that prior snapshot: 0 the same number of (0.0%).

Report change
+0
Death-coded reports
+0
Death-coded share
+0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to B12 changes

Signature read: death-coded share at 11.8% is the most distinctive stamp on B12's FDA AER row.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
34
Total Reports
4
Deaths Reported
11.8%
Death-coded share of reports

Active Ingredients

B12

Administration Routes

UnknownSubcutaneousOralParenteral

Species Affected

Cat 19
Dog 13
Human 1
Lynx 1

Most Affected Breeds

Domestic Shorthair 10
Domestic Mediumhair 5
Unknown 2
Crossbred Canine/dog 2
Mountain Cur 2
Domestic Longhair 2
Mountain Dog - Bernese 2
Terrier - Yorkshire 2
Schnauzer - Miniature 1
Spitz - German Pomeranian 1

Most Reported Reactions

Vomiting 9
Lethargy (see also Central nervous system depression in Neurological) 7
Diarrhoea 6
Decreased appetite 6
Weight loss 5
Ataxia 5
Elevated alanine aminotransferase (ALT) 5
Application site reddening 3
Twitching 3
Seizure NOS 3
Anaemia NOS 3
Skin lesion NOS 3

Outcome Breakdown

Ongoing
17 (50.0%)
Outcome Unknown
8 (23.5%)
Recovered/Normal
5 (14.7%)
Died
2 (5.9%)
Euthanized
2 (5.9%)

B12 Adverse Event Insights

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

What to do with this drug

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for B12 (#1345 of 2,679 by report volume); death-coded 11.8%. PlainBreed drug row · death-coded share stamp 11.8% · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →