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S-Methoprene

Detailed information about S-Methoprene

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:

  • Seizure NOS (1 reports)
  • Restlessness (1 reports)
  • Panting (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:

  • Seizure NOS
  • Restlessness
  • Panting

Most reported reactions:

  • Seizure NOS (1 reports)
  • Restlessness (1 reports)
  • Panting (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, 10:06 AM UTC
  • openFDA case summaries: Source FDA openFDA | Refreshed Feb 9, 2026, 3:22 AM UTC
Image coming soon
S-Methoprene

S-Methoprene

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

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
6
Serious reports
1
Species represented
2
Grouped by Body System
Digestive (2) · Drooling, Diarrhea Skin & allergy (2) · Hair loss at application site, Application site hair loss Neurologic (2) · Seizure NOS, Lethargy (see also Central nervous system depression in Neurological) Effectiveness (4) · Lack of efficacy (ectoparasite) - flea, Lack of efficacy (tick), Lack of efficacy (ectoparasite) - tick NOS Other (9) · Restlessness, Panting, Increased heart rate
Most Reported Reactions
Reaction Body system Cases Species Serious cases
Neurologic 1 Dog 1
Other 1 Dog 0
Other 1 Dog 0
Effectiveness 1 Cat 0
Other 1 Dog 0
Other 1 Cat 0
Neurologic 0 Dog 0
Effectiveness 0 Dog 0

Species coverage: Dog (11) Cat (8)

View detailed reaction table
Reaction Body system Species Seriousness Frequency Reports
Neurologic Dog Serious - 1
Other Dog Non-serious - 1
Other Dog Non-serious - 1
Effectiveness Cat Non-serious - 1
Other Dog Non-serious - 1
Other Cat Non-serious - 1
Neurologic Dog Unknown - -
Effectiveness Dog Unknown - -
Effectiveness Dog Unknown - -
Effectiveness Dog Unknown - -
Skin & allergy Cat Unknown - -
Other Dog Unknown - -
Digestive Cat Unknown - -
Digestive Dog Unknown - -
Other Dog Unknown - -
Other Cat Unknown - -
Other Cat Unknown - -
Other 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, 10:06 AM UTC
  • openFDA case summaries: Source FDA openFDA | Refreshed Feb 9, 2026, 3:22 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 13 • Cat 8 • View
Case summaries: 10 (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
Seizure NOS (1) Restlessness (1) Panting (1) Lack of efficacy (ectoparasite) - flea (1) Increased heart rate (1) Inappropriate urination (1) Lethargy (see also Central nervous system depression in Neurological) (0) Lack of efficacy (tick) (0)

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'), Se… (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).

Digestive
Drooling • Cat Diarrhea • Dog

Showing top 5 for Digestive.

Skin & allergy
Hair loss at application site • Cat Application site hair loss • Cat

Showing top 5 for Skin & allergy.

Neurologic
Seizure NOS (1) • Dog Tiredness (lethargy) • Dog

Showing top 5 for Neurologic.

Effectiveness
Lack of efficacy (ectoparasite) - flea (1) • Cat Lack of efficacy (ectoparasite) - tick NOS • Dog Lack of efficacy (bacteria) - NOS • Dog Lack of efficacy • Dog

Showing top 5 for Effectiveness.

Other
Restlessness (1) • Dog Panting (1) • Dog Increased heart rate (1) • Dog Inappropriate urination (1) • Cat Drunken gait • Dog
Show more (4)
Cough • Dog Application site scab • Cat Application site reddening • Cat Application site irritation • Cat

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

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, 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, Siberian Husky, Male, 3 year, 25.038 kilogram • Drug: MSK, Oral, Dose: 1 dose per animal • Reactions: Panting, Restlessness, Increased heart rate • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-052180
  • Serious AE: No
  • Treated For AE: No
  • Sex: Male
  • Age: 3.00 Year
  • Weight: 25.038 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Dose: 1 dose per animal
Reactions Reported:
Panting Restlessness Increased heart rate
Outcomes: Outcome Unknown

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

Cat, Ragdoll, Male, 12 year, 4.536 kilogram • Drug: MSK, Topical, Dose: 1 dose per animal, Frequency: 11 per day • Reactions: Lack of efficacy (ectoparasite) - flea • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-028654
  • Serious AE: No
  • Treated For AE: No
  • Sex: Male
  • Age: 12.00 Year
  • Weight: 4.536 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Topical
  • Dose: 1 dose per animal
  • Frequency: 11 per day
Reactions Reported:
Lack of efficacy (ectoparasite) - flea
Outcomes: Outcome Unknown

Cat, Cat (unknown), Male, 9 year, 5.443 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-017289
  • Serious AE: No
  • Treated For AE: Yes
  • Sex: Male
  • Age: 9.00 Year
  • Weight: 5.443 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

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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