Drug profile

The FDA adverse-event record for Unspecified Heartworm Preventative

36 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Unspecified Heartworm Preventative. Species, reactions, and outcomes follow.

#1329 of 2,679
by report volume (all drugs)
36
adverse-event reports
8.3%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Unspecified Heartworm Preventative ranks #1311 of 2679 by total reports (36). Death-coded-share rank requires at least 50 reports. National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#1311
This drug, reports of 2679

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Unspecified Heartworm Preventative has 36 reports now versus 36 in that prior snapshot: 0 the same number of (0.0%).

Report change
+0
Death-coded reports
+0
Death-coded share
+0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Unspecified Heartworm Preventative changes

Signature read: death-coded report count at 3 is the most distinctive stamp on Unspecified Heartworm Preventative's FDA AER row.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
36
Total Reports
3
Deaths Reported
8.3%
Death-coded share of reports

Active Ingredients

Unspecified Heartworm Preventative

Administration Routes

UnknownOralTopicalSubcutaneous

Species Affected

Dog 36

Most Affected Breeds

Retriever - Labrador 8
Crossbred Canine/dog 3
Retriever - Golden 3
Spaniel - Cocker American 2
Shih Tzu 2
Beagle 2
Hound (unspecified) 2
Shepherd Dog - German 1
Pug 1
Terrier - Yorkshire 1

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 10
Lack of efficacy - NOS 3
Cough 3
Death by euthanasia 3
Panting 2
Abnormal radiograph finding 2
Lack of efficacy (ectoparasite) - flea 2
Tongue disorder NOS 2
Drooling 2
Lip licking 2
Vomiting 1
INEFFECTIVE, LOSS OF EFFECT 1

Outcome Breakdown

Ongoing
14 (38.9%)
Outcome Unknown
10 (27.8%)
Recovered/Normal
9 (25.0%)
Euthanized
3 (8.3%)

Unspecified Heartworm Preventative Adverse Event Insights

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

What to do with this drug

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Unspecified Heartworm Preventative (#1329 of 2,679 by report volume); death-coded 8.3%. PlainBreed drug row · death-coded report count stamp 3 · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →