Drug profile

The FDA adverse-event record for Narasin

298 FDA reports name Narasin, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#423 of 2,679
by report volume (all drugs)
298
adverse-event reports
73.2%
death-coded share
Pig
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Narasin ranks #423 of 2679 by total reports (298) and #29 of 1130 by death-coded share (73.2%). 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)
#423
This drug, reports of 2679
#29
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. Narasin has 298 reports now versus 296 in that prior snapshot: 2 more (0.7%).

Report change
+2
Death-coded reports
+2
Death-coded share
+0.2 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 Narasin changes

Signature read: Narasin's 73.2% death-coded share is among the highest in the openFDA drug corpus.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
298
Total Reports
218
Deaths Reported
73.2%
Death-coded share of reports

Active Ingredients

Narasin

Administration Routes

OralUnknownRespiratory (Inhalation)Intraocular

Species Affected

Pig 147
Chicken 121
Turkey 7
Cattle 7
Unknown 6
Human 5
Dog 3
Other Reptiles 1
Horse 1

Most Affected Breeds

Pig (unknown) 94
Chicken (unknown) 81
Crossbred Porcine/Pig 37
Chicken (other) 28
Unknown 11
Cornish Cobb 6
Mixed (Pig) 6
Turkey (unknown) 5
Chicken (unspecified) 4
Duroc 3

Most Reported Reactions

Death 163
Lack of efficacy (protozoa) - Coccidia 50
Lameness 46
Death by euthanasia 34
Recumbency 29
Increased mortality rate 29
Vocalisation 24
NT - Abnormal necropsy finding NOS 22
Lack of efficacy - NOS 16
Respiratory tract disorder NOS 16
Rectal prolapse 14
Enteritis 13

Outcome Breakdown

Died
203 (49.2%)
Outcome Unknown
122 (29.5%)
Euthanized
38 (9.2%)
Recovered/Normal
24 (5.8%)
Ongoing
23 (5.6%)
Recovered with Sequela
3 (0.7%)

Narasin: high death-coded share 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 Narasin, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

Similar report volume

Nearest other drugs by FDA report count (298 here).

Similar death-coded share

Nearest other drugs by death-coded share (73.2% 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 Narasin (#423 of 2,679 by report volume); death-coded 73.2%. PlainBreed drug row · death-coded share stamp 73.2% · 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 →