Drug profile

The FDA adverse-event record for Amprolium Ion

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

80
adverse-event reports
20.0%
death-coded share
Cattle
most-reported species
22
Lack of efficacy (protozoa) - Coccidia - 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.
80
Total Reports
16
Deaths Reported
20.0%
Death Rate

Active Ingredients

Amprolium Ion

Administration Routes

OralUnknownOphthalmicTopicalRespiratory (Inhalation)

Species Affected

Cattle 24
Unknown 24
Human 15
Chicken 8
Goat 3
Duck 1
Llama 1
Other Deer 1
Sheep 1
Dog 1

Most Affected Breeds

Unknown 41
Holstein-Friesian also known as Holstein 11
Cattle (unknown) 5
Crossbred Bovine/Cattle 4
Chicken (unknown) 3
Bantam 3
Aberdeen Angus 2
Goat (unknown) 2
Duck (unknown) 1
Guernsey 1

Most Reported Reactions

Lack of efficacy (protozoa) - Coccidia 22
Death 16
Appearance, Abnormal 13
Accidental exposure 12
Lethargy (see also Central nervous system depression in 'Neurological') 8
Diarrhoea 6
Anorexia 6
Contamination, Particulate Matter 6
Potency, Low 5
NT - Abnormal necropsy finding NOS 5
No sign 5
Underdose 5

Outcome Breakdown

Outcome Unknown
31 (53.4%)
Died
16 (27.6%)
Recovered/Normal
8 (13.8%)
Recovered with Sequela
2 (3.4%)
Ongoing
1 (1.7%)

Amprolium Ion Adverse Event Insights

80 reports name Amprolium Ion; 16 recorded a death outcome (20.0% of reported events, not a population-level mortality rate). Active ingredient: Amprolium Ion. Administration routes: Oral, Unknown, Ophthalmic, Topical.

By species: Cattle (24 reports), Unknown (24 reports), Human (15 reports). By breed: Unknown (41), Holstein-Friesian also known as Holstein (11), Cattle (unknown) (5).

Leading clinical signs: Lack of efficacy (protozoa) - Coccidia (22), Death (16), Appearance, Abnormal (13), Accidental exposure (12). Outcome, 58 coded reports: Outcome Unknown leads at 53.4%.

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.