Drug profile

The FDA adverse-event record for Lactulose

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

265
adverse-event reports
20.4%
death-coded share
Cat
most-reported species
46
Vomiting - top reaction
Verify with FDA CVM →
Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
265
Total Reports
54
Deaths Reported
20.4%
Death Rate

Active Ingredients

Lactulose

Administration Routes

OralUnknownRectalOtherSubcutaneous

Species Affected

Cat 175
Dog 88
Human 1
Other Birds 1

Most Affected Breeds

Domestic Shorthair 114
Terrier - Yorkshire 19
Domestic Mediumhair 11
Chihuahua 8
Cat (other) 8
Cat (unknown) 7
Domestic Longhair 7
Retriever - Labrador 5
Schnauzer - Miniature 5
Shepherd Dog - German 5

Most Reported Reactions

Vomiting 46
Lethargy (see also Central nervous system depression in 'Neurological') 45
Death by euthanasia 33
Anorexia 31
Constipation 29
Weight loss 27
Other abnormal test result NOS 27
Diarrhoea 25
Seizure NOS 25
Decreased appetite 25
Ataxia 22
Lack of efficacy - NOS 21

Outcome Breakdown

Ongoing
92 (34.7%)
Outcome Unknown
60 (22.6%)
Recovered/Normal
59 (22.3%)
Euthanized
33 (12.5%)
Died
21 (7.9%)

Lactulose Adverse Event Insights

265 reports name Lactulose; 54 recorded a death outcome (20.4% of reported events, not a population-level mortality rate). Active ingredient: Lactulose. Administration routes: Oral, Unknown, Rectal, Other.

By species: Cat (175 reports), Dog (88 reports), Human (1 reports). By breed: Domestic Shorthair (114), Terrier - Yorkshire (19), Domestic Mediumhair (11).

Leading clinical signs: Vomiting (46), Lethargy (see also Central nervous system depression in 'Neurological') (45), Death by euthanasia (33), Anorexia (31). Outcome, 265 coded reports: Ongoing leads at 34.7%.

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.