Drug profile

The FDA adverse-event record for Fipronil/S-Methoprene

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

#773 of 2,679
by report volume (all drugs)
101
adverse-event reports
11.9%
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 #772 of 2679 by total reports (101) and #459 of 1130 by death-coded share (11.9%). 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)
#772
This drug, reports of 2679
#459
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 101 reports now versus 101 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/S-Methoprene changes

Signature read: 101 reports place Fipronil/S-Methoprene in the upper third of FDA AER volume (#773 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.
101
Total Reports
12
Deaths Reported
11.9%
Death-coded share of reports

Active Ingredients

Fipronil/S-Methoprene

Administration Routes

TopicalUnknownOral

Species Affected

Dog 87
Cat 14

Most Affected Breeds

Retriever - Labrador 15
Domestic Shorthair 10
Terrier - West Highland White 7
Spaniel - King Charles Cavalier 6
Chihuahua 5
Shih Tzu 5
Shepherd Dog - German 3
Shepherd Dog - Australian 3
Spaniel - Cocker American 2
Collie (unspecified) 2

Most Reported Reactions

Lethargy (see also Central nervous system depression in 'Neurological') 24
Other abnormal test result NOS 14
Vomiting 12
Diarrhoea 11
Panting 8
Seizure NOS 8
Pruritus 8
Lack of efficacy (ectoparasite) - flea 8
Decreased appetite 8
Emesis 7
Anorexia 7
Abnormal radiograph finding 7

Outcome Breakdown

Recovered/Normal
44 (43.6%)
Ongoing
28 (27.7%)
Outcome Unknown
16 (15.8%)
Euthanized
6 (5.9%)
Died
6 (5.9%)
Recovered with Sequela
1 (1.0%)

Fipronil/S-Methoprene: high 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.

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 (101 here).

Similar death-coded share

Nearest other drugs by death-coded share (11.9% 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 (#773 of 2,679 by report volume); death-coded 11.9%. PlainBreed drug row · report volume stamp 101 · 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 →