Reaction profile

The FDA adverse-event record for decreased mean corpuscular volume (mcv)

135 FDA adverse-event reports reference decreased mean corpuscular volume (mcv) (VeDDRA 2855). Plate codes and volume neighbourhood below; species, breeds, and drugs follow.

#1240 of 2,481
by report volume (all reactions)
135
reports citing this reaction
31.9%
death-coded share
Dog
most-affected species

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. Decreased mean corpuscular volume (MCV) has 135 reports now versus 125 in that prior snapshot: 10 more (8.0%).

Report change
+10
Death-coded reports
+7
Death-coded share
+3.1 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 Decreased mean corpuscular volume (MCV) changes

FDA AER · VeDDRA plate

Code 2855 VOL-LOW

VOL-LOW · DEATH-HOT · MID-PACK · PHOTO-FINISH · SPECIES-DOG · DRUG-LEAD · DESK-WIDE · BOOK-FULL

  • VOL-LOW 135 reports
  • DEATH-HOT 31.9%
  • MID-PACK #1240/2481
  • PHOTO-FINISH Abnormal serum protei…
  • SPECIES-DOG Dog · 114
  • DRUG-LEAD Maropitant Citrate · 23
  • DESK-WIDE 20 breeds
  • BOOK-FULL 8/8 fields

Nearest volume peer: Abnormal serum protein NOS (±0 reports)

Upper-third death-coded share drives the outcome stamps on this plate; volume band, corpus rank, and co-report peers follow. Not a clinical diagnosis.

Report-volume neighbourhood around Decreased mean corpuscular volume

Highest and lowest poles plus nearest volume peers, not a full 2,500-reaction corpus board reprint.

Vomiting · highest174348Abnormal serum protei… · near135Cholangiohepatitis · near135Decreased mean corpus… · thi…135Laminitis · near135Other coagulation abn… · near135Urinary tract neoplas… · low…10
FDA AER report volume · neighbourhood around Decreased mean corpuscular volume (MCV)

Decreased mean corpuscular volume (MCV): high death-coded share in the FDA AER plate

Signature read: Decreased mean corpuscular volume (MCV)'s 31.9% death-coded share is among the highest in the openFDA reaction corpus. Report volume sits in the middle third of the reaction corpus. Death-coded share is upper-third: 43 of 135 reports (31.9% of named reports). Nearest volume peer: Abnormal serum protein NOS (±0 reports). Lead species Dog (114). Lead co-reported drug Maropitant Citrate (23).

Read these counts as reporting volume, not risk: per our methodology, A high death-coded share in FDA filings does not prove causation; co-reporting is voluntary temporal association only. Browse the full reactions index or the about page for how PlainBreed frames FDA CVM extracts.

Species Most Affected

Dog 114
Cat 19
Cattle 1
Horse 1

Breeds Most Affected

Retriever - Labrador 17
Domestic Shorthair 12
Shepherd Dog - German 10
Crossbred Canine/dog 6
Schnauzer - Miniature 5
Beagle 5
Bulldog - French 4
Retriever - Golden 4
Hound - Basset 3
Dachshund (unspecified) 3

Associated Drugs

Maropitant Citrate 23
Gabapentin 22
Afoxolaner 16
Ilunocitinib 15
Enrofloxacin 14
Carprofen 13
Oclacitinib Maleate 12
Metronidazole 11
Prednisone 11
Fluid Therapy 10
Buprenorphine 9
Bedinvetmab 9
Ampicillin Sodium/Sulbactam Sodium 9
Milbemycin Oxime + Praziquantel 8
Amoxicillin + Clavulanic Acid 8
Ondansetron 8
Dexamethasone Sodium Phosphate 7
Doxycycline 7
Trilostane 6
Bordetella Vaccine 6

Nationwide reactions with similar profiles

Two openFDA-derived peer sets for Decreased mean corpuscular volume (MCV), both floored at ≥50 reports so the neighborhoods stay in the advertised mass (the volume chart above is the unfloored photo-finish strip).

Similar report volume

Nearest other reactions by FDA report count (135 here).

Similar death-coded share

Nearest other reactions by death-coded share (31.9% here), distinct from the volume row.

What to do with this reaction

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 Decreased mean corpuscular volume (MCV) (#1240 of 2,481 by report volume); death-coded 31.9%. PlainBreed reaction plate · death-coded share stamp 31.9% · 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 →