Drug profile

The FDA adverse-event record for Melengestrol Acetate

285 FDA reports name Melengestrol Acetate, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#438 of 2,679
by report volume (all drugs)
285
adverse-event reports
17.2%
death-coded share
Cattle
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Melengestrol Acetate ranks #436 of 2679 by total reports (285) and #297 of 1130 by death-coded share (17.2%). 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)
#436
This drug, reports of 2679
#297
This drug, death share of 1130

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. Melengestrol Acetate has 285 reports now versus 285 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 Melengestrol Acetate changes

Signature read: death-coded report count at 49 is the most distinctive stamp on Melengestrol Acetate'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.
285
Total Reports
49
Deaths Reported
17.2%
Death-coded share of reports

Active Ingredients

Melengestrol Acetate

Administration Routes

OralUnknown

Species Affected

Cattle 262
Unknown 22
Human 1

Most Affected Breeds

Mixed (Cattle) 121
Cattle (other) 49
Cattle (unknown) 43
Crossbred Bovine/Cattle 26
Unknown 24
Holstein-Friesian also known as Holstein 8
Aberdeen Angus 7
Charolais 2
Simmental 1
Jersey 1

Most Reported Reactions

INEFFECTIVE, ESTRUS SUPPRESSIO 110
Lack of efficacy - NOS 84
Death 27
Lameness 19
Pneumonia 14
Increased sexual interest 13
Death by euthanasia 12
No sign 11
Unclassifiable adverse event 11
Sexual disorder NOS (see 'Reproductive' for named sexual disorders) 10
Bloated 9
Found dead 9

Outcome Breakdown

Outcome Unknown
203 (68.4%)
Died
39 (13.1%)
Recovered/Normal
33 (11.1%)
Euthanized
13 (4.4%)
Recovered with Sequela
7 (2.4%)
Ongoing
2 (0.7%)

Melengestrol Acetate: high death-coded share in the FDA AER row

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.

High-volume nationwide drug peers

Two openFDA-derived peer sets for Melengestrol Acetate, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

Similar death-coded share

Nearest other drugs by death-coded share (17.2% here), distinct from the volume row.

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 Melengestrol Acetate (#438 of 2,679 by report volume); death-coded 17.2%. PlainBreed drug row · death-coded report count stamp 49 · 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 →