Reaction profile

The FDA adverse-event record for muscle stiffness

565 FDA adverse-event reports reference muscle stiffness (VeDDRA 609). See the species, breeds, and drugs most associated with it below.

565
reports citing this reaction
17.2%
death-coded share
Dog
most-affected species
Milbemycin Oxime + Spinosad
most-associated drug
Verify with FDA CVM →
565
Total Reports
97
Deaths
17.2%
Death Rate

Species Most Affected

Dog 404
Horse 93
Cat 39
Cattle 19
Human 5
Sheep 2
Hamster 1
Other Equids 1
Goat 1

Breeds Most Affected

Retriever - Labrador 38
Crossbred Canine/dog 31
Quarter Horse 28
Chihuahua 24
Domestic Shorthair 19
Thoroughbred 19
Boxer (German Boxer) 18
Maltese 18
Shih Tzu 15
Terrier - Yorkshire 13

Associated Drugs

Milbemycin Oxime + Spinosad 58
Ceftiofur Crystalline Free Acid 47
Spinosad 44
Carprofen 32
Afoxolaner 23
Ivermectin + Pyrantel As Pamoate Salt 22
Bedinvetmab 18
Moxidectin 17
Pyrantel Pamoate;Sarolaner 17
Selamectin 16
Polysulfated Glycosaminoglycan 13
Enrofloxacin 12
Dexmedetomidine Hydrochloride 11
Oclacitinib Maleate 11
Fluralaner Chew Tablets 11
Ivermectin, Pyrantel 10
Fluralaner 13.64% 12-Week Chew 10
Imidacloprid + Moxidectin 9
Pergolide Mesylate 9
Glycosaminoglycan Polysulfate 8

Muscle stiffness Reaction Insights

565 reports name Muscle stiffness; 97 recorded a death outcome (17.2% of reported events, not a population-level mortality rate). VeDDRA code: 609.

By species: Dog (404 reports), Horse (93 reports), Cat (39 reports). By breed: Retriever - Labrador (38), Crossbred Canine/dog (31), Quarter Horse (28).

Most co-reported drugs: Milbemycin Oxime + Spinosad (58 reports), Ceftiofur Crystalline Free Acid (47 reports), Spinosad (44 reports), Carprofen (32 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.