Drug profile

The FDA adverse-event record for Rejensa

11 FDA reports name Rejensa, a lower-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#2500 of 2,679
by report volume (all drugs)
11
adverse-event reports
36.4%
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, Rejensa ranks #2412 of 2679 by total reports (11). 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)
#2412
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. Rejensa has 11 reports now versus 11 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 Rejensa changes

Signature read: 11 reports place Rejensa in the lower third of FDA AER volume (#2500 of 2,679).

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
11
Total Reports
4
Deaths Reported
36.4%
Death-coded share of reports

Active Ingredients

Rejensa

Administration Routes

OralUnknown

Species Affected

Dog 11

Most Affected Breeds

Retriever - Labrador 3
Dog (unknown) 1
Poodle (unspecified) 1
Terrier - Bull - Staffordshire 1
Beagle 1
Collie - Border 1
Pointing Dog - Hungarian Short-haired (Vizsla) 1
Sheepdog - Old English (Bobtail) 1
Shepherd Dog - German 1

Most Reported Reactions

Death 3
Vomiting 3
Lethargy (see also Central nervous system depression in Neurological) 2
Diarrhoea 2
Panting 2
Dyspnoea 1
Seizure NOS 1
Fever 1
Lack of efficacy - NOS 1
Limb weakness 1
Gum disorder NOS 1
Hypertension 1

Outcome Breakdown

Ongoing
5 (45.5%)
Died
3 (27.3%)
Recovered/Normal
1 (9.1%)
Euthanized
1 (9.1%)
Outcome Unknown
1 (9.1%)

Rejensa: 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.

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 Rejensa (#2500 of 2,679 by report volume); death-coded 36.4%. PlainBreed drug row · report volume stamp 11 · 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 →