Drug profile

The FDA adverse-event record for Mitotane

41 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Mitotane. Species, reactions, and outcomes follow.

#1239 of 2,679
by report volume (all drugs)
41
adverse-event reports
9.8%
death-coded share
Dog
most-reported species
Verify with FDA CVM →

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Mitotane ranks #1235 of 2679 by total reports (41). Death-coded-share rank requires at least 50 reports. National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#1235
This drug, reports of 2679

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Mitotane has 41 reports now versus 41 in that prior snapshot: 0 the same number of (0.0%).

Report change
+0
Death-coded reports
+0
Death-coded share
−0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Mitotane changes

Signature read: report volume at 41 is the most distinctive stamp on Mitotane's FDA AER row.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
41
Total Reports
4
Deaths Reported
9.8%
Death-coded share of reports

Active Ingredients

Mitotane

Administration Routes

OralUnknown

Species Affected

Dog 41

Most Affected Breeds

Schnauzer (unspecified) 3
Lhasa Apso 3
Terrier - Yorkshire 3
Crossbred Canine/dog 3
Dog (unknown) 2
Shepherd Dog - German 2
Dachshund (unspecified) 2
Boxer (German Boxer) 2
Poodle - Miniature 2
Mastiff 2

Most Reported Reactions

Lethargy (see also Central nervous system depression in 'Neurological') 8
Elevated serum alkaline phosphatase (SAP) 7
Weight loss 6
Diarrhoea 6
Hypoadrenocorticism 6
Elevated alanine aminotransferase (ALT) 6
Seizure NOS 5
Underdose 4
Abnormal adrenocorticotropic hormone (ACTH) stimulation test 4
Pancreatitis 4
Decreased appetite 4
INEFFECTIVE, CUSHINGS 3

Outcome Breakdown

Outcome Unknown
15 (36.6%)
Ongoing
13 (31.7%)
Recovered/Normal
7 (17.1%)
Euthanized
3 (7.3%)
Recovered with Sequela
2 (4.9%)
Died
1 (2.4%)

Mitotane Adverse Event Insights

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.

What to do with this drug

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Mitotane (#1239 of 2,679 by report volume); death-coded 9.8%. PlainBreed drug row · report volume stamp 41 · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →