Drug profile

The FDA adverse-event record for Heartgard Plus

138 FDA reports name Heartgard Plus, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#655 of 2,679
by report volume (all drugs)
138
adverse-event reports
2.2%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Heartgard Plus ranks #655 of 2679 by total reports (138) and #975 of 1130 by death-coded share (2.2%). 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)
#655
This drug, reports of 2679
#975
This drug, death share of 1130

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. Heartgard Plus has 138 reports now versus 138 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 Heartgard Plus changes

Signature read: Heartgard Plus's 2.2% death-coded share is among the lowest in the openFDA drug corpus.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
138
Total Reports
3
Deaths Reported
2.2%
Death-coded share of reports

Active Ingredients

Heartgard Plus

Administration Routes

OralUnknown

Species Affected

Dog 138

Most Affected Breeds

Retriever - Labrador 16
Crossbred Canine/dog 11
Chihuahua 10
Terrier - Bull - American Pit 8
Retriever - Golden 7
Shepherd Dog - German 6
Beagle 5
Terrier (unspecified) 4
Shepherd Dog - Australian 3
Shepherd Dog - Belgian Malinois 3

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 83
Seizure NOS 8
Polyuria 7
Urinary incontinence 6
Lethargy (see also Central nervous system depression in Neurological) 5
Decreased appetite 4
Vomiting 4
Emesis (multiple) 4
Twitching 4
Diarrhoea 4
Urinary tract infection 4
Ataxia 3

Outcome Breakdown

Ongoing
104 (75.4%)
Outcome Unknown
19 (13.8%)
Recovered/Normal
12 (8.7%)
Euthanized
2 (1.4%)
Died
1 (0.7%)

Heartgard Plus: low death-coded share in the FDA AER row

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.

High-volume nationwide drug peers

Two openFDA-derived peer sets for Heartgard Plus, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

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 Heartgard Plus (#655 of 2,679 by report volume); death-coded 2.2%. PlainBreed drug row · death-coded share stamp 2.2% · 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 →