Drug profile

The FDA adverse-event record for Narasin

295 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Narasin. See the species affected, top reactions, and outcomes below.

295
adverse-event reports
72.9%
death-coded share
Pig
most-reported species
162
Death - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
295
Total Reports
215
Deaths Reported
72.9%
Death Rate

Active Ingredients

Narasin

Administration Routes

OralUnknownRespiratory (Inhalation)Intraocular

Species Affected

Pig 147
Chicken 118
Turkey 7
Cattle 7
Unknown 6
Human 5
Dog 3
Other Reptiles 1
Horse 1

Most Affected Breeds

Pig (unknown) 94
Chicken (unknown) 78
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 162
Lack of efficacy (protozoa) - Coccidia 48
Lameness 46
Death by euthanasia 34
Recumbency 29
Increased mortality rate 26
Vocalisation 24
NT - Abnormal necropsy finding NOS 22
Lack of efficacy - NOS 16
Respiratory tract disorder NOS 16
Rectal prolapse 14
Accidental exposure 12

Outcome Breakdown

Died
200 (48.8%)
Outcome Unknown
122 (29.8%)
Euthanized
38 (9.3%)
Recovered/Normal
24 (5.9%)
Ongoing
23 (5.6%)
Recovered with Sequela
3 (0.7%)

Narasin Adverse Event Insights

295 reports name Narasin; 215 recorded a death outcome (72.9% of reported events, not a population-level mortality rate). Active ingredient: Narasin. Administration routes: Oral, Unknown, Respiratory (Inhalation), Intraocular.

By species: Pig (147 reports), Chicken (118 reports), Turkey (7 reports). By breed: Pig (unknown) (94), Chicken (unknown) (78), Crossbred Porcine/Pig (37).

Leading clinical signs: Death (162), Lack of efficacy (protozoa) - Coccidia (48), Lameness (46), Death by euthanasia (34). Outcome, 410 coded reports: Died leads at 48.8%.

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.

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

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.