Reaction profile
The FDA adverse-event record for opisthotonus
211 FDA adverse-event reports reference opisthotonus (VeDDRA 644). Plate codes and volume neighbourhood below; species, breeds, and drugs follow.
- #1005 of 2,481
- by report volume (all reactions)
- 211
- reports citing this reaction
- 35.1%
- 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. Opisthotonus has 211 reports now versus 207 in that prior snapshot: 4 more (1.9%).
- Report change
- +4
- Death-coded reports
- +1
- Death-coded share
- −0.2 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 Opisthotonus changesFDA AER · VeDDRA plate
Code 644 VOL-LOW
VOL-LOW · DEATH-HOT · MID-PACK · PHOTO-FINISH · SPECIES-DOG · DRUG-LEAD · DESK-WIDE · BOOK-FULL
- VOL-LOW 211 reports
- DEATH-HOT 35.1%
- MID-PACK #1005/2481
- PHOTO-FINISH Chewing - oral cavity…
- SPECIES-DOG Dog · 163
- DRUG-LEAD Milbemycin Oxime… · 27
- DESK-WIDE 20 breeds
- BOOK-FULL 8/8 fields
Nearest volume peer: Chewing - oral cavity disorder (see also 'Pruritus') (±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 Opisthotonus
Highest and lowest poles plus nearest volume peers, not a full 2,500-reaction corpus board reprint.
Opisthotonus: high death-coded share in the FDA AER plate
Signature read: Opisthotonus's 35.1% 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: 74 of 211 reports (35.1% of named reports). Nearest volume peer: Chewing - oral cavity disorder (see also 'Pruritus') (±0 reports). Lead species Dog (163). Lead co-reported drug Milbemycin Oxime + Spinosad (27).
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
Breeds Most Affected
Associated Drugs
Nationwide reactions with similar profiles
Two openFDA-derived peer sets for Opisthotonus, 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 (211 here).
Similar death-coded share
Nearest other reactions by death-coded share (35.1% here), distinct from the volume row.
What to do with this reaction
- Compare Opisthotonus's report profile against similar reactions nationwide. See similar reactions
- Read how death-coded share differs from a mortality rate before drawing conclusions. Understanding adverse events
- Browse the full reaction directory to compare report counts across reaction types. All reactions
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
Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →