Reaction profile

The FDA adverse-event record for hypertonia

51 FDA adverse-event reports reference hypertonia (VeDDRA 1529). See the species, breeds, and drugs most associated with it below.

51
reports citing this reaction
25.5%
death-coded share
Dog
most-affected species
Ketamine Hydrochloride
most-associated drug
Verify with FDA CVM →
51
Total Reports
13
Deaths
25.5%
Death Rate

Species Most Affected

Dog 32
Cat 13
Horse 3
Other 1
Mouse 1
Donkey 1

Breeds Most Affected

Cat (unknown) 6
Domestic (unspecified) 5
Pointing Dog - German Short-haired 4
Crossbred Canine/dog 4
Retriever - Labrador 3
Unknown 2
Maltese 2
Terrier - Yorkshire 2
Cattle Dog - Australian (blue heeler, red heeler, Queensland cattledog) 2
Spaniel - King Charles Cavalier 2

Associated Drugs

Ketamine Hydrochloride 6
Isoflurane 4
Tiletamine, Zolazepam 4
Selamectin 3
Milbemycin, Lufenuron 3
Moxidectin 3
Carprofen 3
Butorphanol 3
Meloxicam 2
Ivermectin, Pyrantel 2
Dexmedetomidine Hydrochloride 2
Ivermectin 2
Trilostane 2
Gabapentin 2
Methocarbamol 2
Midazolam 2
Diphenhydramine 2
Xylazine 1
Spinosad 1
Milbemycin 1

Hypertonia Reaction Insights

51 reports name Hypertonia; 13 recorded a death outcome (25.5% of reported events, not a population-level mortality rate). VeDDRA code: 1529.

By species: Dog (32 reports), Cat (13 reports), Horse (3 reports). By breed: Cat (unknown) (6), Domestic (unspecified) (5), Pointing Dog - German Short-haired (4).

Most co-reported drugs: Ketamine Hydrochloride (6 reports), Isoflurane (4 reports), Tiletamine, Zolazepam (4 reports), Selamectin (3 reports).

Read these counts as reporting volume, not risk: per our methodology, co-reporting reflects temporal association captured in voluntary submissions, not proof that a drug caused this reaction. A widely-prescribed drug will rack up more raw co-reports at an identical true rate than a rarely-used one, so compare within similar-exposure products.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.