Drug profile

The FDA adverse-event record for Altrenogest

88 FDA reports name Altrenogest, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#828 of 2,679
by report volume (all drugs)
88
adverse-event reports
2.3%
death-coded share
Unknown
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Altrenogest ranks #827 of 2679 by total reports (88) and #968 of 1130 by death-coded share (2.3%). 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)
#827
This drug, reports of 2679
#968
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. Altrenogest has 88 reports now versus 87 in that prior snapshot: 1 more (1.1%).

Report change
+1
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 Altrenogest changes

Signature read: Altrenogest's 2.3% death-coded share is among the lowest in the openFDA drug corpus.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
88
Total Reports
2
Deaths Reported
2.3%
Death-coded share of reports

Active Ingredients

Altrenogest

Administration Routes

UnknownOralTopical

Species Affected

Unknown 35
Horse 24
Human 19
Pig 10

Most Affected Breeds

Unknown 54
Quarter Horse 6
Pig (unknown) 6
Horse (unknown) 5
Arab 2
Warmblood - Dutch 2
Crossbred Porcine/Pig 2
Mixed (Pig) 1
Belgian Draft, also called Brabant or Brabants trekpaard 1
Welsh Pony 1

Most Reported Reactions

Unclassifiable adverse event 19
Accidental exposure 17
Containers, Leaking 16
INEFFECTIVE, ESTRUS SUPPRESSIO 8
Rash 5
Vials, Leaking 5
Closure, Abnormal 5
Caps, Abnormal 4
Abdominal pain 4
INEFFECTIVE, ESTRUS SYNCHRONIZ 4
Disorders of menstrual cycle NOS 4
Restlessness 4

Outcome Breakdown

Outcome Unknown
7 (43.8%)
Ongoing
5 (31.3%)
Recovered/Normal
2 (12.5%)
Died
1 (6.3%)
Euthanized
1 (6.3%)

Altrenogest: low 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 Altrenogest, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

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 Altrenogest (#828 of 2,679 by report volume); death-coded 2.3%. PlainBreed drug row · death-coded share stamp 2.3% · 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 →