Drug profile

The FDA adverse-event record for Cephalexin

2,780 FDA reports name Cephalexin, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#81 of 2,679
by report volume (all drugs)
2,780
adverse-event reports
9.6%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Cephalexin ranks #81 of 2679 by total reports (2,780) and #557 of 1130 by death-coded share (9.6%). 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)
#81
This drug, reports of 2679
#557
This drug, death share of 1130

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. Cephalexin has 2,780 reports now versus 2,758 in that prior snapshot: 22 more (0.8%).

Report change
+22
Death-coded reports
+3
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 Cephalexin changes

Signature read: death-coded report count at 268 is the most distinctive stamp on Cephalexin'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.
2,780
Total Reports
268
Deaths Reported
9.6%
Death-coded share of reports

Active Ingredients

Cephalexin

Administration Routes

OralUnknownTopicalIntravenousSubcutaneousOtherOphthalmicParenteral

Species Affected

Dog 2,600
Cat 89
Unknown 86
Human 3
Ferret 2

Most Affected Breeds

Retriever - Labrador 405
Shepherd Dog - German 165
Retriever - Golden 132
Crossbred Canine/dog 111
Pit Bull 107
Terrier - Bull - American Pit 92
Boxer (German Boxer) 90
Unknown 90
Bulldog 84
Domestic Shorthair 56

Most Reported Reactions

Vomiting 752
Emesis 373
Lethargy (see also Central nervous system depression in 'Neurological') 367
Diarrhoea 222
Overdose 219
Other abnormal test result NOS 214
Accidental exposure 207
Lack of efficacy - NOS 182
Anorexia 170
Death by euthanasia 137
Seizure NOS 135
Weight loss 122

Outcome Breakdown

Recovered/Normal
978 (36.2%)
Ongoing
779 (28.9%)
Outcome Unknown
596 (22.1%)
Euthanized
136 (5.0%)
Died
135 (5.0%)
Recovered with Sequela
74 (2.7%)

Cephalexin: high report volume in the FDA AER row

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.

High-volume nationwide drug peers

Two openFDA-derived peer sets for Cephalexin, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

Similar death-coded share

Nearest other drugs by death-coded share (9.6% here), distinct from the volume row.

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 Cephalexin (#81 of 2,679 by report volume); death-coded 9.6%. PlainBreed drug row · death-coded report count stamp 268 · 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 →