Drug profile

The FDA adverse-event record for Unspecified Heartworm Prevention

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

#933 of 2,679
by report volume (all drugs)
71
adverse-event reports
8.5%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Unspecified Heartworm Prevention ranks #928 of 2679 by total reports (71) and #622 of 1130 by death-coded share (8.5%). 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)
#928
This drug, reports of 2679
#622
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. Unspecified Heartworm Prevention has 71 reports now versus 70 in that prior snapshot: 1 more (1.4%).

Report change
+1
Death-coded reports
+0
Death-coded share
−0.1 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 Prevention changes

Signature read: report volume at 71 is the most distinctive stamp on Unspecified Heartworm Prevention'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.
71
Total Reports
6
Deaths Reported
8.5%
Death-coded share of reports

Active Ingredients

Unspecified Heartworm Prevention

Administration Routes

UnknownOralSubcutaneous

Species Affected

Dog 71

Most Affected Breeds

Retriever - Golden 7
Dog (unknown) 4
Retriever - Labrador 4
Beagle 4
Boxer (German Boxer) 4
Crossbred Canine/dog 4
Shih Tzu 3
Doberman Pinscher 3
Shepherd (unspecified) 3
Siberian Husky 3

Most Reported Reactions

Vomiting 15
Lack of efficacy (endoparasite) - heartworm 12
Diarrhoea 9
Lack of efficacy - NOS 8
Lethargy (see also Central nervous system depression in 'Neurological') 7
Weight loss 6
Underdose 5
Lethargy (see also Central nervous system depression in Neurological) 5
Other abnormal test result NOS 4
Death by euthanasia 4
Weakness 4
Panting 4

Outcome Breakdown

Outcome Unknown
29 (40.8%)
Ongoing
22 (31.0%)
Recovered/Normal
14 (19.7%)
Euthanized
4 (5.6%)
Died
2 (2.8%)

Unspecified Heartworm Prevention 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.

Nationwide drugs with similar profiles

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

Similar report volume

Nearest other drugs by FDA report count (71 here).

Similar death-coded share

Nearest other drugs by death-coded share (8.5% here), distinct from the volume row.

What to do with this drug

  • Compare Unspecified Heartworm Prevention's report volume and death-coded share against similar drugs nationwide. See similar drugs
  • Read how death-coded share differs from a mortality rate before drawing conclusions. Understanding adverse events
  • Browse the full drug directory to compare report counts across products. All drugs

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 Prevention (#933 of 2,679 by report volume); death-coded 8.5%. PlainBreed drug row · report volume stamp 71 · 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 →