Drug profile

The FDA adverse-event record for Amprolium

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

222
adverse-event reports
17.1%
death-coded share
Unknown
most-reported species
72
Appearance, Abnormal - 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.
222
Total Reports
38
Deaths Reported
17.1%
Death Rate

Active Ingredients

Amprolium

Administration Routes

UnknownOralTopicalRespiratory (Inhalation)

Species Affected

Unknown 117
Cattle 55
Human 21
Chicken 6
Goat 5
Sheep 5
Dog 4
Horse 4
Turkey 3
Rabbit 1

Most Affected Breeds

Unknown 138
Holstein-Friesian also known as Holstein 13
Cattle (unknown) 13
Aberdeen Angus 9
Cattle (other) 9
Mixed (Cattle) 6
Chicken (unknown) 5
Goat (unknown) 4
Sheep (unknown) 3
Turkey (unknown) 3

Most Reported Reactions

Appearance, Abnormal 72
Contamination, Particulate Matter 35
Death 29
Lack of efficacy (protozoa) - Coccidia 25
Potency, Low 16
Unclassifiable adverse event 15
Accidental exposure 15
Diarrhoea 13
Bloody diarrhoea 9
Lack of efficacy - NOS 9
Uncoded sign 9
Product Defect, General 7

Outcome Breakdown

Died
38 (44.7%)
Outcome Unknown
22 (25.9%)
Recovered/Normal
13 (15.3%)
Ongoing
7 (8.2%)
Euthanized
5 (5.9%)

Amprolium Adverse Event Insights

222 reports name Amprolium; 38 recorded a death outcome (17.1% of reported events, not a population-level mortality rate). Active ingredient: Amprolium. Administration routes: Unknown, Oral, Topical, Respiratory (Inhalation).

By species: Unknown (117 reports), Cattle (55 reports), Human (21 reports). By breed: Unknown (138), Holstein-Friesian also known as Holstein (13), Cattle (unknown) (13).

Leading clinical signs: Appearance, Abnormal (72), Contamination, Particulate Matter (35), Death (29), Lack of efficacy (protozoa) - Coccidia (25). Outcome, 85 coded reports: Died leads at 44.7%.

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.