Reaction profile

The FDA adverse-event record for ineffective, worms nos

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

883
reports citing this reaction
6.2%
death-coded share
Dog
most-affected species
Ivermectin + Pyrantel As Pamoate Salt
most-associated drug
Verify with FDA CVM →
883
Total Reports
55
Deaths
6.2%
Death Rate

Species Most Affected

Dog 592
Cattle 127
Cat 82
Horse 36
Chicken 11
Sheep 10
Goat 9
Pig 3
Turkey 3
Other 2

Breeds Most Affected

Dog (unknown) 106
Retriever - Labrador 55
Crossbred Canine/dog 48
Cattle (other) 34
Domestic Shorthair 33
Retriever - Golden 29
Cat (unknown) 27
Pit Bull 26
Chihuahua 23
Mixed (Cattle) 19

Associated Drugs

Ivermectin + Pyrantel As Pamoate Salt 112
Fenbendazol Granules 61
Febantel + Praziquantel + Pyrantel Pamoate 51
Selamectin 47
Moxidectin 41
Milbemycin Oxime, Lufenuron 38
Milbemycin Oxime + Spinosad 37
Praziquantel 34
Doramectin 33
Fenbendazole 29
Praziquantel + Pyrantel Pamoate 29
Fenbendazol Suspension 29
Pyrantel Pamoate;Sarolaner 22
Milbemycin Oxime + Praziquantel 21
Pyrantel Pamoate 19
Albendazole 18
Emodepside + Praziquantel 16
Milbemycin/Lufenuron/Pzq Chew 16
Ivermectin 14
Pyrantel Tartrate 14

INEFFECTIVE, WORMS NOS Reaction Insights

883 reports name INEFFECTIVE, WORMS NOS; 55 recorded a death outcome (6.2% of reported events, not a population-level mortality rate). VeDDRA code: 99160.

By species: Dog (592 reports), Cattle (127 reports), Cat (82 reports). By breed: Dog (unknown) (106), Retriever - Labrador (55), Crossbred Canine/dog (48).

Most co-reported drugs: Ivermectin + Pyrantel As Pamoate Salt (112 reports), Fenbendazol Granules (61 reports), Febantel + Praziquantel + Pyrantel Pamoate (51 reports), Selamectin (47 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.