Reaction profile

The FDA adverse-event record for tonic-clonic seizure

285 FDA adverse-event reports reference tonic-clonic seizure (VeDDRA 646). Plate codes and volume neighbourhood below; species, breeds, and drugs follow.

#890 of 2,481
by report volume (all reactions)
285
reports citing this reaction
20.7%
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. Tonic-clonic seizure has 285 reports now versus 280 in that prior snapshot: 5 more (1.8%).

Report change
+5
Death-coded reports
+0
Death-coded share
−0.4 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 Tonic-clonic seizure changes

FDA AER · VeDDRA plate

Code 646 VOL-LOW

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

  • VOL-LOW 285 reports
  • DEATH-HOT 20.7%
  • MID-PACK #890/2481
  • PHOTO-FINISH Uveitis
  • SPECIES-DOG Dog · 254
  • DRUG-LEAD Sarolaner · 32
  • DESK-WIDE 20 breeds
  • BOOK-FULL 8/8 fields

Nearest volume peer: Uveitis (±0 reports)

Instrument codes from this reaction’s FDA CVM adverse-event extract: volume band, death-coded share, corpus rank, photo-finish peer, lead species, lead drug, breed desk, and book completeness. Not a clinical diagnosis.

Report-volume neighbourhood around Tonic-clonic seizure

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

Vomiting · highest174348Impaired propriocepti… · near286Tonic-clonic seizure · this …285Uveitis · near285Growling · near284Cardiomyopathy · near283Urinary tract neoplas… · low…10
FDA AER report volume · neighbourhood around Tonic-clonic seizure

What the FDA AER plate says about Tonic-clonic seizure

Signature read: 59 death-coded reports is a heavy tail count for Tonic-clonic seizure in the CVM extract. Report volume sits in the middle third of the reaction corpus. 59 of 285 reports were death-coded (20.7% of named reports, not a population mortality rate). Nearest volume peer: Uveitis (±0 reports). Lead species Dog (254). Lead co-reported drug Sarolaner (32).

Read these counts as reporting volume, not risk: per our methodology, Lead co-reported drug Sarolaner appears in filings alongside this reaction; that is association, not causation. Browse the full reactions index or the about page for how PlainBreed frames FDA CVM extracts.

Species Most Affected

Dog 254
Cat 20
Horse 8
Rabbit 1
Cattle 1
Human 1

Breeds Most Affected

Retriever - Labrador 26
Crossbred Canine/dog 22
Domestic Shorthair 12
Shih Tzu 11
Shepherd Dog - German 10
Collie - Border 9
Shepherd Dog - Australian 8
Retriever - Golden 8
Chihuahua 8
Spaniel - King Charles Cavalier 7

Associated Drugs

Sarolaner 32
Fluralaner Chew Tablets 31
Bedinvetmab 22
Carprofen 19
Pyrantel Pamoate;Sarolaner 17
Milbemycin Oxime + Spinosad 15
Afoxolaner 15
Oclacitinib Maleate 14
Ivermectin + Pyrantel As Pamoate Salt 12
Maropitant Citrate 10
Levetiracetam 9
Dexmedetomidine Hydrochloride 9
Milbemycin Oxime, Lufenuron 9
Diazepam 9
Grapiprant 9
Butorphanol 8
Isoflurane 8
Selamectin 8
Gabapentin 8
Phenobarbital 7

Nationwide reactions with similar profiles

Two openFDA-derived peer sets for Tonic-clonic seizure, 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 (285 here).

Similar death-coded share

Nearest other reactions by death-coded share (20.7% 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 Tonic-clonic seizure (#890 of 2,481 by report volume); death-coded 20.7%. PlainBreed reaction plate · death-coded report count stamp 59 · 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 →