Drug profile

The FDA adverse-event record for Clorsulon, Ivermectin

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

87
adverse-event reports
12.6%
death-coded share
Cattle
most-reported species
17
Seal, 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.
87
Total Reports
11
Deaths Reported
12.6%
Death Rate

Active Ingredients

Clorsulon, Ivermectin

Administration Routes

SubcutaneousUnknownOralTopicalIntramuscular

Species Affected

Cattle 48
Unknown 27
Human 6
Dog 5
Other 1

Most Affected Breeds

Unknown 34
Cattle (unknown) 22
Aberdeen Angus 9
Crossbred Bovine/Cattle 7
Cattle (other) 4
Mixed (Cattle) 2
Crossbred Canine/dog 2
Holstein-Friesian also known as Holstein 2
Limousin 1
Beefmaster 1

Most Reported Reactions

Seal, Abnormal 17
INEFFECTIVE, PARASITE(S) NOS 8
Death 7
INEFFECTIVE, LICE BITING 7
Unclassifiable adverse event 7
Accidental exposure 7
Lack of efficacy (ectoparasite) - lice 6
Injection site swelling 5
Alopecia NOS 4
Injection site pain 4
Lack of efficacy - NOS 3
Trembling 3

Outcome Breakdown

Died
11 (91.7%)
Recovered/Normal
1 (8.3%)

Clorsulon, Ivermectin Adverse Event Insights

87 reports name Clorsulon, Ivermectin; 11 recorded a death outcome (12.6% of reported events, not a population-level mortality rate). Active ingredient: Clorsulon, Ivermectin. Administration routes: Subcutaneous, Unknown, Oral, Topical.

By species: Cattle (48 reports), Unknown (27 reports), Human (6 reports). By breed: Unknown (34), Cattle (unknown) (22), Aberdeen Angus (9).

Leading clinical signs: Seal, Abnormal (17), INEFFECTIVE, PARASITE(S) NOS (8), Death (7), INEFFECTIVE, LICE BITING (7). Outcome, 12 coded reports: Died leads at 91.7%.

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.