Drug profile

The FDA adverse-event record for Acetylcysteine

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

36
adverse-event reports
55.6%
death-coded share
Dog
most-reported species
18
Elevated alanine aminotransferase (ALT) - 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.
36
Total Reports
20
Deaths Reported
55.6%
Death Rate

Active Ingredients

Acetylcysteine

Administration Routes

UnknownIntravenousOralParenteral

Species Affected

Dog 33
Cat 2
Horse 1

Most Affected Breeds

Shepherd Dog - German 4
Crossbred Canine/dog 3
Poodle (unspecified) 3
Corgi - Welsh Pembroke 3
Siberian Husky 3
Dog (other) 2
Retriever - Labrador 2
Domestic Shorthair 2
Pit Bull 2
Terrier - Boston 2

Most Reported Reactions

Elevated alanine aminotransferase (ALT) 18
Elevated total bilirubin 17
Abnormal ultrasound finding 17
Death by euthanasia 14
Vomiting 12
Hypokalaemia 11
Other abnormal test result NOS 10
Lethargy (see also Central nervous system depression in Neurological) 10
Leucocytosis NOS 9
Icterus 9
Elevated serum alkaline phosphatase (ALP) 9
Anorexia 8

Outcome Breakdown

Euthanized
14 (36.8%)
Ongoing
9 (23.7%)
Outcome Unknown
7 (18.4%)
Died
6 (15.8%)
Recovered/Normal
1 (2.6%)
Recovered with Sequela
1 (2.6%)

Acetylcysteine Adverse Event Insights

36 reports name Acetylcysteine; 20 recorded a death outcome (55.6% of reported events, not a population-level mortality rate). Active ingredient: Acetylcysteine. Administration routes: Unknown, Intravenous, Oral, Parenteral.

By species: Dog (33 reports), Cat (2 reports), Horse (1 reports). By breed: Shepherd Dog - German (4), Crossbred Canine/dog (3), Poodle (unspecified) (3).

Leading clinical signs: Elevated alanine aminotransferase (ALT) (18), Elevated total bilirubin (17), Abnormal ultrasound finding (17), Death by euthanasia (14). Outcome, 38 coded reports: Euthanized leads at 36.8%.

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.