Drug profile

The FDA adverse-event record for Fipronil + (S)-Methoprene

378 FDA reports name Fipronil + (S)-Methoprene, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#364 of 2,679
by report volume (all drugs)
378
adverse-event reports
1.6%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Fipronil + (S)-Methoprene ranks #364 of 2679 by total reports (378) and #1022 of 1130 by death-coded share (1.6%). 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)
#364
This drug, reports of 2679
#1022
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. Fipronil + (S)-Methoprene has 378 reports now versus 371 in that prior snapshot: 7 more (1.9%).

Report change
+7
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 + (S)-Methoprene changes

Signature read: 378 reports place Fipronil + (S)-Methoprene in the upper third of FDA AER volume (#364 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.
378
Total Reports
6
Deaths Reported
1.6%
Death-coded share of reports

Active Ingredients

Fipronil + (S)-Methoprene

Administration Routes

TopicalUnknownOralCutaneousIntraocular

Species Affected

Dog 316
Cat 62

Most Affected Breeds

Retriever - Labrador 42
Domestic Shorthair 24
Dog (unknown) 17
Crossbred Canine/dog 15
Cat (unknown) 15
Shepherd Dog - German 14
Domestic Longhair 11
Beagle 10
Shepherd Dog - Australian 10
Shih Tzu 9

Most Reported Reactions

Emesis 94
Lack of efficacy (ectoparasite) - flea 67
Vomiting 47
Lethargy (see also Central nervous system depression in 'Neurological') 42
Lack of efficacy - NOS 41
Diarrhoea 22
Other abnormal test result NOS 18
Behavioural disorder NOS 16
Lack of efficacy (flea) 14
Lack of efficacy (endoparasite) - heartworm 14
Panting 12
Seizure NOS 11

Outcome Breakdown

Outcome Unknown
168 (44.4%)
Recovered/Normal
147 (38.9%)
Ongoing
41 (10.8%)
Recovered with Sequela
16 (4.2%)
Died
5 (1.3%)
Euthanized
1 (0.3%)

Fipronil + (S)-Methoprene: 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 Fipronil + (S)-Methoprene, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

Similar report volume

Nearest other drugs by FDA report count (378 here).

Similar death-coded share

Nearest other drugs by death-coded share (1.6% here), distinct from the volume row.

What to do with this drug

  • Compare Fipronil + (S)-Methoprene'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 Fipronil + (S)-Methoprene (#364 of 2,679 by report volume); death-coded 1.6%. PlainBreed drug row · report volume stamp 378 · 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 →