Drug profile

The FDA adverse-event record for Fipronil/Methoprene

16 FDA reports name Fipronil/Methoprene, a lower-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#2018 of 2,679
by report volume (all drugs)
16
adverse-event reports
12.5%
death-coded share
Cat
most-reported species
Verify with FDA CVM →

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Fipronil/Methoprene ranks #1995 of 2679 by total reports (16). 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)
#1995
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. Fipronil/Methoprene has 16 reports now versus 16 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 Fipronil/Methoprene changes

Signature read: 16 reports place Fipronil/Methoprene in the lower third of FDA AER volume (#2018 of 2,679).

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
16
Total Reports
2
Deaths Reported
12.5%
Death-coded share of reports

Active Ingredients

Fipronil/Methoprene

Administration Routes

TopicalUnknown

Species Affected

Cat 8
Dog 8

Most Affected Breeds

Domestic Shorthair 8
Terrier - Yorkshire 2
Spitz - American Eskimo Dog 1
Collie (unspecified) 1
Shepherd Dog - Belgian Laekenois 1
Shepherd Dog - German 1
Mixed (Dog) 1
Terrier - Border 1

Most Reported Reactions

Lack of efficacy (ectoparasite) - flea 4
Stiffness limb 3
Hyperactivity 2
Vocalisation 2
Scratching 2
Seizure NOS 2
Cardiac enlargement 2
Limb weakness 2
Paraparesis 2
Pulmonary disorder NOS 2
Urinary retention 2
Lateral recumbency 2

Outcome Breakdown

Recovered/Normal
7 (43.8%)
Ongoing
5 (31.3%)
Outcome Unknown
2 (12.5%)
Euthanized
2 (12.5%)

Fipronil/Methoprene: lower report volume 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.

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 Fipronil/Methoprene (#2018 of 2,679 by report volume); death-coded 12.5%. PlainBreed drug row · report volume stamp 16 · 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 →