Reaction profile

The FDA adverse-event record for muscle rigidity

183 FDA adverse-event reports reference muscle rigidity (VeDDRA 1628). See the species, breeds, and drugs most associated with it below.

183
reports citing this reaction
19.1%
death-coded share
Dog
most-affected species
Afoxolaner
most-associated drug
Verify with FDA CVM →
183
Total Reports
35
Deaths
19.1%
Death Rate

Species Most Affected

Dog 156
Cat 18
Horse 7
Cattle 2

Breeds Most Affected

Chihuahua 16
Retriever - Labrador 13
Crossbred Canine/dog 12
Shih Tzu 12
Domestic Shorthair 9
Dog (unknown) 6
Maltese 5
Quarter Horse 4
Collie - Border 4
Retriever - Golden 4

Associated Drugs

Afoxolaner 25
Milbemycin Oxime + Spinosad 18
Ivermectin + Pyrantel As Pamoate Salt 18
Carprofen 15
Isoflurane 12
Fluralaner Chew Tablets 11
Alfaxalone 9
Propofol 8
Gabapentin 8
Lotilaner 7
Spinosad 6
Oclacitinib Maleate 6
Midazolam 6
Fluralaner 13.64% 12-Week Chew 6
Pyrantel Pamoate;Sarolaner 6
Bedinvetmab 6
Imidacloprid + Moxidectin 5
Hydromorphone 5
Dexmedetomidine Hydrochloride 5
Ketamine Hydrochloride 4

Muscle rigidity Reaction Insights

183 reports name Muscle rigidity; 35 recorded a death outcome (19.1% of reported events, not a population-level mortality rate). VeDDRA code: 1628.

By species: Dog (156 reports), Cat (18 reports), Horse (7 reports). By breed: Chihuahua (16), Retriever - Labrador (13), Crossbred Canine/dog (12).

Most co-reported drugs: Afoxolaner (25 reports), Milbemycin Oxime + Spinosad (18 reports), Ivermectin + Pyrantel As Pamoate Salt (18 reports), Carprofen (15 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.