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Fipronil

Detailed information about Fipronil

Official label facts Owner quick guide first Marketing clearly labeled
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Reviewed / Updated / Sources

Reviewed: Not available

Updated: February 12, 2026, 10:44 PM UTC

Sources:

Pet Owner Quick Guide

Start here first for the simple next-step summary.

Used for:

Your vet decides this. Here's what owners typically ask/watch for.

What to watch for:

  • Unclassifiable adverse event (1 reports)
  • Skin lesion NOS (1 reports)
  • Skin haemorrhage NOS (1 reports)

When to call the vet:

  • Repeated vomiting or diarrhea.
  • Severe lethargy (hard to wake, very low energy).
  • Collapse or fainting.
  • Trouble breathing.
  • Facial swelling or hives.
  • Blood in vomit or stool.

What to ask your vet today:

  • Is this medicine the right fit for my pet’s current symptoms?
  • Which warning signs mean I should call back right away?
  • How should I handle missed doses or refusal to take the medicine?
Safety & side effects

What to watch:

  • Unclassifiable adverse event
  • Skin lesion NOS
  • Skin haemorrhage NOS

Most reported reactions:

  • Unclassifiable adverse event (1 reports)
  • Skin lesion NOS (1 reports)
  • Skin haemorrhage NOS (1 reports)

When to call your vet:

  • Repeated vomiting or diarrhea.
  • Severe lethargy (hard to wake, very low energy).
  • Collapse or fainting.
  • Trouble breathing.
Talk to a Vet / Find a Vet Near You Start Symptom Intake

Data freshness: source data appears current.

Latest refresh: Mar 21, 2026, 10:01 a.m.

Data freshness
  • Medication catalog: Source Roxee | Refreshed Feb 12, 2026, 10:44 PM UTC
  • Animal Drug Product Listing Directory (NDC): Source FDA | Refreshed Mar 21, 2026, 10:01 AM UTC
    Package/product NDCs from FDA’s electronic listing directory (XLS).
  • openFDA reaction terms: Source FDA openFDA | Refreshed Mar 16, 2026, 10:05 AM UTC
  • openFDA case summaries: Source FDA openFDA | Refreshed Feb 17, 2026, 11:06 AM UTC
Image coming soon
Fipronil

Fipronil

Drug type: Generic ingredient • Generic profile • No FDA branded products linked

Species: Both

Manufacturer: Not available (source)

Quick Facts

Official label facts first, then secondary summaries. Marketing content is separated below.

Species: Both
Manufacturer: Not available
Identifiers:
NDC Package: 73377-155-01 NDC Product: 73377

Adverse Reactions

Snapshot first, detailed rows second. This section summarizes signal data and is not a diagnosis.

Tap or hover a reaction to see what it means in plain language.

Tracked signals
19
Reported cases
16
Serious reports
5
Species represented
2
Grouped by Body System
Skin & allergy (4) · Itching, Chewing - pruritus, Hair loss at application site Neurologic (1) · Seizure NOS Behavior (3) · Biting -aggression, Behavioral disorder (unspecified), Biting -aggression (see also Skin and appendages disorders) Effectiveness (1) · Lack of efficacy (ectoparasite) - flea Other (10) · Unclassifiable adverse event, Skin scab, Skin lesion NOS
Most Reported Reactions
Reaction Body system Cases Species Serious cases
Other 1 Dog 1
Other 1 Dog 1
Other 1 Dog 1
Neurologic 1 Dog 1
Skin & allergy 1 Dog 1
Other 1 Cat 0
Other 1 Cat 0
Other 1 Cat 0

Species coverage: Dog (10) Cat (9)

View detailed reaction table
Reaction Body system Species Seriousness Frequency Reports
Other Dog Serious - 1
Other Cat Non-serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Neurologic Dog Serious - 1
Other Cat Non-serious - 1
Other Cat Non-serious - 1
Other Dog Non-serious - 1
Effectiveness Dog Non-serious - 1
Skin & allergy Dog Serious - 1
Other Dog Non-serious - 1
Other Dog Non-serious - 1
Other Dog Non-serious - 1
Skin & allergy Cat Non-serious - 1
Behavior Cat Non-serious - 1
Behavior Cat Non-serious - 1
Skin & allergy Cat Unknown - -
Behavior Cat Unknown - -
Skin & allergy Cat Unknown - -
Source metadata:
Veterinary reference (advanced)

Canonical medication sections are above. This legacy block remains available for deeper cross-reference without cluttering the primary workflow.

At a Glance

Quick facts and links to official labeling and safety signals.

Data freshness
  • Medication catalog: Source Roxee | Refreshed Feb 12, 2026, 10:44 PM UTC
  • Animal Drug Product Listing Directory (NDC): Source FDA | Refreshed Mar 21, 2026, 10:01 AM UTC
    Package/product NDCs from FDA’s electronic listing directory (XLS).
  • openFDA reaction terms: Source FDA openFDA | Refreshed Mar 16, 2026, 10:05 AM UTC
  • openFDA case summaries: Source FDA openFDA | Refreshed Feb 17, 2026, 11:06 AM UTC
Official (FDA)
Identity: Generic ingredient • No FDA branded products linked
No official FDA brand rows linked yet for this ingredient.
Case-reported brands (openFDA): MSK
Catalog species: Both
Safety (openFDA)
Top reactions: Dog 20 • Cat 13 • View
Case summaries: 11 (showing 8) • View
openFDA reports are unverified and do not prove causation.
Diagnosis Codes

Diagnosis-code mappings are not available for this medication yet.

Counseling and Monitoring Highlights

Global Pet owner/Vet mode is controlled in the header. This section avoids duplicate in-page persona tabs.

Top reaction signals
Unclassifiable adverse event (1) Skin lesion NOS (1) Skin haemorrhage NOS (1) Seizure NOS (1) Itching (1) Skin scab (1) Scratching (1) Rolling (1)

Identifiers & Packages

Normalized identifiers (NDC/NADA/ANADA) and package metadata from regulator listings.

Identifiers
NDC Package: 73377-155-01 NDC Product: 73377
Package NDC Product NDC Form / Route Status
73377-155-01 73377 -

Data Sources & Change Log

Every non-trivial field is expected to include provenance and update timestamps.

Official 1 Clinical 0 Manufacturer 0 Marketing 0
Current Field Facts
  • side_effects: Top reported reactions (openFDA): Lack of efficacy (ectoparasite) - flea, Vomiting, Lethargy (see also Central nervous system depression in 'Neurological'), Di… (Official, 2026-02-12)
Recent Revisions
  • side_effects updated 2026-02-12 22:44 by etl_backfill • Backfilled from existing medication fields

Top Reported Reactions (openFDA)

De-duplicated reaction terms grouped by body system from FDA openFDA reports (not verified; does not prove causation).

Skin & allergy
Itching (1) • Dog Chewing - pruritus (1) • Cat Hair loss at application site • Cat Application site hair loss • Cat

Showing top 5 for Skin & allergy.

Neurologic
Seizure NOS (1) • Dog

Showing top 5 for Neurologic.

Behavior
Biting -aggression (1) • Cat Behavioral disorder (1) • Cat

Showing top 5 for Behavior.

Effectiveness
Lack of efficacy (ectoparasite) - flea (1) • Dog

Showing top 5 for Effectiveness.

Other
Unclassifiable adverse event (1) • Dog Skin scab (1) • Cat Skin lesion NOS (1) • Dog Skin haemorrhage NOS (1) • Dog Scratching (1) • Cat
Show more (5)
Rolling (1) • Cat Leucopenia NOS (1) • Dog Decreased red blood cell count (1) • Dog Decreased haemoglobin (1) • Dog Decreased haematocrit (1) • Dog

Showing top 5 for Other.

Data source: FDA openFDA Animal & Veterinary adverse event reports.

Adverse Event Case Summaries (openFDA)

These are individual FDA adverse event reports. They are unverified and do not prove the medication caused the reaction.

Dog, Terrier - Yorkshire, Mixed, 6 year, 2.722 kilogram • Drug: MSK, Topical, Dose: 1 dose per animal, Frequency: 1 per month • Reactions: Lack of efficacy (ectoparasite) - flea • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-055722
  • Serious AE: No
  • Treated For AE: Yes
  • Sex: Mixed
  • Age: 6.00 Year
  • Weight: 2.722 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Topical
  • Dose: 1 dose per animal
  • Frequency: 1 per month
Reactions Reported:
Lack of efficacy (ectoparasite) - flea
Outcomes: Outcome Unknown

Cat, Cat (unknown), Male • Drug: MSK, Suspension, Topical, Dose: 1 tube per animal • Reactions: Lack of efficacy (ectoparasite) - flea, Chewing - pruritus, Biting -aggression, Scratching, Behavioral disorder (unspecified)… • Outcome: Ongoing

  • Report ID: USA-USFDACVM-2025-US-054396
  • Serious AE: No
  • Treated For AE: Yes
  • Sex: Male
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Topical
  • Form: Suspension
  • Dose: 1 tube per animal
Reactions Reported:
Lack of efficacy (ectoparasite) - flea Chewing - pruritus Biting -aggression Scratching Behavioral disorder (unspecified) Rolling
Outcomes: Ongoing

Dog, Shih Tzu, Female, 4 year, 4.99 kilogram • Drug: MSK, Topical, Dose: 1 dose per animal • Reactions: Lack of efficacy (ectoparasite) - flea • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-053057
  • Serious AE: No
  • Treated For AE: No
  • Sex: Female
  • Age: 4.00 Year
  • Weight: 4.990 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Topical
  • Dose: 1 dose per animal
Reactions Reported:
Lack of efficacy (ectoparasite) - flea
Outcomes: Outcome Unknown

Dog, Dog (unknown), Female • Drug: MSK, Suspension, Topical, Dose: 1 tube per animal, Frequency: 1 per day • Reactions: Lack of efficacy (ectoparasite) - flea, Skin haemorrhage NOS, Unclassifiable adverse event, Skin lesion NOS, Behavioral disorder (unspecified)… • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-053915
  • Serious AE: Yes
  • Treated For AE: Yes
  • Sex: Female
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Topical
  • Form: Suspension
  • Dose: 1 tube per animal
  • Frequency: 1 per day
Reactions Reported:
Lack of efficacy (ectoparasite) - flea Skin haemorrhage NOS Unclassifiable adverse event Skin lesion NOS Behavioral disorder (unspecified) Itching
Outcomes: Outcome Unknown

Dog, Spaniel (unspecified), Female, 7 year, 17.69 kilogram • Drug: MSK, Topical, Dose: 1 dose per animal, Frequency: 31 per day • Reactions: Lack of efficacy (ectoparasite) - flea • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-053037
  • Serious AE: No
  • Treated For AE: Yes
  • Sex: Female
  • Age: 7.00 Year
  • Weight: 17.690 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Topical
  • Dose: 1 dose per animal
  • Frequency: 31 per day
Reactions Reported:
Lack of efficacy (ectoparasite) - flea
Outcomes: Outcome Unknown

Dog, Crossbred Canine/dog, Female, 7 week, 18.597 kilogram • Drug: MSK, Unknown • Reactions: Seizure NOS • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-052767
  • Serious AE: Yes
  • Treated For AE: No
  • Sex: Female
  • Age: 7.00 Week
  • Weight: 18.597 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Unknown
Reactions Reported:
Seizure NOS
Outcomes: Outcome Unknown

Dog, Retriever - Labrador, Female, 6.75 year, 40.6 kilogram • Drug: MSK, Unknown • Reactions: Decreased haemoglobin, Leucopenia NOS, Decreased haematocrit, Decreased red blood cell count • Outcome: Recovered/Normal

  • Report ID: USA-USFDACVM-2025-US-052522
  • Serious AE: No
  • Treated For AE: No
  • Sex: Female
  • Age: 6.75 Year
  • Weight: 40.600 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Unknown
Reactions Reported:
Decreased haemoglobin Leucopenia NOS Decreased haematocrit Decreased red blood cell count
Outcomes: Recovered/Normal

Cat, Domestic Longhair, Mixed, 6 month, 1.361 kilogram • Drug: MSK, Topical, Dose: 1 dose per animal • Reactions: Lack of efficacy (ectoparasite) - flea • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-043462
  • Serious AE: No
  • Treated For AE: Yes
  • Sex: Mixed
  • Age: 6.00 Month
  • Weight: 1.361 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Topical
  • Dose: 1 dose per animal
Reactions Reported:
Lack of efficacy (ectoparasite) - flea
Outcomes: Outcome Unknown

Data source: FDA openFDA Animal & Veterinary adverse event reports.

Overdose Information

No approved overdose-management text is linked yet. If overdose is suspected, contact a veterinarian or emergency clinic immediately.

Storage & Handling

No approved storage guidance is linked yet for this ingredient. Use manufacturer packaging and veterinary guidance for handling/storage.

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