Reaction profile

The FDA adverse-event record for heart block 2nd degree

53 FDA adverse-event reports reference heart block 2nd degree (VeDDRA 2432). See the species, breeds, and drugs most associated with it below.

53
reports citing this reaction
11.3%
death-coded share
Dog
most-affected species
Dexmedetomidine Hydrochloride
most-associated drug
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53
Total Reports
6
Deaths
11.3%
Death Rate

Species Most Affected

Dog 45
Horse 4
Cat 2
Ferret 1
Pigeon 1

Breeds Most Affected

Dog (unknown) 5
Retriever - Labrador 5
Terrier - Yorkshire 3
Mixed (Dog) 3
Unknown 2
Terrier - Bull - American Pit 2
Schnauzer - Miniature 2
Terrier - West Highland White 2
Thoroughbred 2
Collie - Border 2

Associated Drugs

Dexmedetomidine Hydrochloride 21
Atipamezole Hydrochloride 6
Butorphanol Tartrate 5
Butorphanol 5
Dexmedetomidine 5
Detomidine Hydrochloride 4
Buprenorphine 4
Fluralaner Chew Tablets 3
Propofol 3
Anesthetic 3
Maropitant Citrate 3
Hydromorphone 3
Moxidectin 3
Canine Cough Syrup 3
Midazolam 3
Carprofen 2
Cefazolin 2
Hydromorphone Hcl 2
Isoflurane 2
Pimobendan 2

Heart block 2nd degree Reaction Insights

53 reports name Heart block 2nd degree; 6 recorded a death outcome (11.3% of reported events, not a population-level mortality rate). VeDDRA code: 2432.

By species: Dog (45 reports), Horse (4 reports), Cat (2 reports). By breed: Dog (unknown) (5), Retriever - Labrador (5), Terrier - Yorkshire (3).

Most co-reported drugs: Dexmedetomidine Hydrochloride (21 reports), Atipamezole Hydrochloride (6 reports), Butorphanol Tartrate (5 reports), Butorphanol (5 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.