Drug profile

The FDA adverse-event record for Narasin + Nicarbazin

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

160
adverse-event reports
68.1%
death-coded share
Chicken
most-reported species
68
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.
160
Total Reports
109
Deaths Reported
68.1%
Death Rate

Active Ingredients

NarasinNicarbazin

Administration Routes

OralUnknownRespiratory (Inhalation)Ophthalmic

Species Affected

Chicken 156
Human 2
Unknown 1
Dog 1

Most Affected Breeds

Chicken (unknown) 121
Chicken (other) 28
Chicken (unspecified) 4
Unknown 3
Cornish Cobb 1
Crossbred Chicken 1
Dog (unknown) 1
Mixed (Chicken) 1

Most Reported Reactions

Death 68
Lack of efficacy (protozoa) - Coccidia 53
Increased mortality rate 40
Lack of efficacy - NOS 17
NT - Abnormal necropsy finding NOS 15
Enteritis 14
Loss of egg quantity 14
Digestive tract disorder NOS 12
Loss of egg quality 11
Abnormal necropsy finding 9
Death by euthanasia 8
Dermatitis 7

Outcome Breakdown

Died
104 (51.7%)
Outcome Unknown
66 (32.8%)
Euthanized
14 (7.0%)
Recovered/Normal
12 (6.0%)
Recovered with Sequela
4 (2.0%)
Ongoing
1 (0.5%)

Narasin + Nicarbazin Adverse Event Insights

160 reports name Narasin + Nicarbazin; 109 recorded a death outcome (68.1% of reported events, not a population-level mortality rate). Active ingredients: Narasin, Nicarbazin. Administration routes: Oral, Unknown, Respiratory (Inhalation), Ophthalmic.

By species: Chicken (156 reports), Human (2 reports), Unknown (1 reports). By breed: Chicken (unknown) (121), Chicken (other) (28), Chicken (unspecified) (4).

Leading clinical signs: Death (68), Lack of efficacy (protozoa) - Coccidia (53), Increased mortality rate (40), Lack of efficacy - NOS (17). Outcome, 201 coded reports: Died leads at 51.7%.

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.