Reaction profile

The FDA adverse-event record for lack of efficacy (ectoparasite) - demodex

248 FDA adverse-event reports reference lack of efficacy (ectoparasite) - demodex (VeDDRA 2789). See the species, breeds, and drugs most associated with it below.

248
reports citing this reaction
1.2%
death-coded share
Dog
most-affected species
Milbemycin Oxime + Spinosad
most-associated drug
Verify with FDA CVM →
248
Total Reports
3
Deaths
1.2%
Death Rate

Species Most Affected

Dog 236
Cat 10
Cattle 2

Breeds Most Affected

Dog (unknown) 29
Crossbred Canine/dog 23
Retriever - Labrador 18
Shepherd Dog - German 18
Pug 11
Pit Bull 11
Chihuahua 11
Shih Tzu 7
Retriever - Golden 6
Bulldog 5

Associated Drugs

Milbemycin Oxime + Spinosad 45
Amitraz 33
Fluralaner Chew Tablets 30
Fluralaner 13.64% 12-Week Chew 25
Selamectin 20
Spinosad 19
Ivermectin 17
Afoxolaner 16
Pyrantel Pamoate;Sarolaner 15
Sarolaner 12
Cephalexin 8
Moxidectin 6
Imidacloprid + Moxidectin 5
Lufenuron + Milbemycin Oxime 5
Cefpodoxime Proxetil 5
Prednisone 5
Cefpodoxime 5
Imidacloprid And Moxidectin 5
Oclacitinib Maleate 5
Lotilaner 5

Lack of efficacy (ectoparasite) - Demodex Reaction Insights

248 reports name Lack of efficacy (ectoparasite) - Demodex; 3 recorded a death outcome (1.2% of reported events, not a population-level mortality rate). VeDDRA code: 2789.

By species: Dog (236 reports), Cat (10 reports), Cattle (2 reports). By breed: Dog (unknown) (29), Crossbred Canine/dog (23), Retriever - Labrador (18).

Most co-reported drugs: Milbemycin Oxime + Spinosad (45 reports), Amitraz (33 reports), Fluralaner Chew Tablets (30 reports), Fluralaner 13.64% 12-Week Chew (25 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.