Drug profile

The FDA adverse-event record for Monensin Sodium

2,499 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Monensin Sodium. See the species affected, top reactions, and outcomes below.

2,499
adverse-event reports
51.9%
death-coded share
Cattle
most-reported species
1,148
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.
2,499
Total Reports
1,296
Deaths Reported
51.9%
Death Rate

Active Ingredients

Monensin Sodium

Administration Routes

OralUnknownRespiratory (Inhalation)OtherIntraocularOphthalmic

Species Affected

Cattle 1,874
Turkey 189
Horse 112
Chicken 94
Unknown 71
Goat 41
Sheep 33
Pig 29
Dog 15
Human 15

Most Affected Breeds

Holstein-Friesian also known as Holstein 838
Cattle (unknown) 482
Turkey (unknown) 166
Crossbred Bovine/Cattle 131
Mixed (Cattle) 106
Aberdeen Angus 104
Unknown 98
Jersey 90
Cattle (other) 88
Horse (unknown) 75

Most Reported Reactions

Death 1,148
Diarrhoea 242
Decreased appetite 201
Milk production decrease 196
Lack of efficacy (protozoa) - Coccidia 196
Not eating 184
Lack of efficacy - NOS 172
NT - Abnormal necropsy finding NOS 155
Anorexia 147
Recumbency 131
Alteration of milk quality 124
Loose stool 117

Outcome Breakdown

Died
1,265 (40.0%)
Outcome Unknown
1,092 (34.5%)
Recovered/Normal
424 (13.4%)
Ongoing
210 (6.6%)
Recovered with Sequela
90 (2.8%)
Euthanized
84 (2.7%)

Monensin Sodium Adverse Event Insights

2,499 reports name Monensin Sodium; 1,296 recorded a death outcome (51.9% of reported events, not a population-level mortality rate). Active ingredient: Monensin Sodium. Administration routes: Oral, Unknown, Respiratory (Inhalation), Other.

By species: Cattle (1,874 reports), Turkey (189 reports), Horse (112 reports). By breed: Holstein-Friesian also known as Holstein (838), Cattle (unknown) (482), Turkey (unknown) (166).

Leading clinical signs: Death (1,148), Diarrhoea (242), Decreased appetite (201), Milk production decrease (196). Outcome, 3,165 coded reports: Died leads at 40.0%.

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.