Reaction profile

The FDA adverse-event record for slow heart rate

172 FDA adverse-event reports reference slow heart rate (VeDDRA 190). See the species, breeds, and drugs most associated with it below.

172
reports citing this reaction
18.6%
death-coded share
Dog
most-affected species
Milbemycin Oxime + Spinosad
most-associated drug
Verify with FDA CVM →
172
Total Reports
32
Deaths
18.6%
Death Rate

Species Most Affected

Dog 138
Cat 29
Human 2
Horse 2
Parrot 1

Breeds Most Affected

Domestic Shorthair 16
Retriever - Labrador 14
Terrier - Yorkshire 10
Dog (unknown) 9
Chihuahua 8
Shih Tzu 7
Dachshund (unspecified) 6
Crossbred Canine/dog 6
Cat (unknown) 5
Collie - Border 4

Associated Drugs

Milbemycin Oxime + Spinosad 30
Isoflurane 17
Buprenorphine 15
Dexmedetomidine Hydrochloride 13
Moxidectin 12
Dexmedetomidine 11
Maropitant Citrate 11
Spinosad 9
Carprofen 8
Trilostane 8
Butorphanol 8
Ketamine 8
Atipamezole Hydrochloride 6
Milbemycin Oxime + Praziquantel 6
Meloxicam 5
Diazepam 5
Fipronil 9.8%/S-Methoprene 8.8%/ Amitraz 22.1% Spot-On 4
Rabies Vaccine 4
Fluralaner Chew Tablets 4
Acepromazine 4

Slow heart rate Reaction Insights

172 reports name Slow heart rate; 32 recorded a death outcome (18.6% of reported events, not a population-level mortality rate). VeDDRA code: 190.

By species: Dog (138 reports), Cat (29 reports), Human (2 reports). By breed: Domestic Shorthair (16), Retriever - Labrador (14), Terrier - Yorkshire (10).

Most co-reported drugs: Milbemycin Oxime + Spinosad (30 reports), Isoflurane (17 reports), Buprenorphine (15 reports), Dexmedetomidine Hydrochloride (13 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.