Reaction profile

The FDA adverse-event record for ineffective, worms

465 FDA adverse-event reports reference ineffective, worms (VeDDRA 99160). See the species, breeds, and drugs most associated with it below.

465
reports citing this reaction
4.1%
death-coded share
Dog
most-affected species
Ivermectin + Pyrantel As Pamoate Salt
most-associated drug
Verify with FDA CVM →
465
Total Reports
19
Deaths
4.1%
Death Rate

Species Most Affected

Dog 363
Cattle 47
Cat 31
Sheep 8
Horse 6
Goat 4
Pig 2
Unknown 1
Buffalo 1
Quail 1

Breeds Most Affected

Dog (unknown) 66
Retriever - Labrador 43
Crossbred Canine/dog 30
Retriever - Golden 20
Shepherd Dog - German 17
Mixed (Cattle) 16
Domestic Shorthair 16
Cattle (other) 14
Pit Bull 11
Chihuahua 11

Associated Drugs

Ivermectin + Pyrantel As Pamoate Salt 104
Febantel + Praziquantel + Pyrantel Pamoate 55
Milbemycin Oxime + Spinosad 43
Fenbendazol Granules 29
Lufenuron + Milbemycin Oxime 28
Imidacloprid + Moxidectin 19
Praziquantel + Pyrantel Pamoate 18
Albendazole 16
Lufenuron + Milbemycin Oxime + Praziquantel 16
Selamectin 15
Praziquantel 14
Doramectin 13
Milbemycin Oxime, Lufenuron 11
Fenbendazol Suspension 11
Praziquantel/Pyrantel Pamoate/Febantel 9
Milbemycin Oxime 6
Ivermectin 6
Pyrantel Pamoate (Pyrantel Embonate) 6
Afoxolaner 6
Doramectin; Phenol 5

INEFFECTIVE, WORMS Reaction Insights

465 reports name INEFFECTIVE, WORMS; 19 recorded a death outcome (4.1% of reported events, not a population-level mortality rate). VeDDRA code: 99160.

By species: Dog (363 reports), Cattle (47 reports), Cat (31 reports). By breed: Dog (unknown) (66), Retriever - Labrador (43), Crossbred Canine/dog (30).

Most co-reported drugs: Ivermectin + Pyrantel As Pamoate Salt (104 reports), Febantel + Praziquantel + Pyrantel Pamoate (55 reports), Milbemycin Oxime + Spinosad (43 reports), Fenbendazol Granules (29 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.