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Roxee Medication Guide

Spinosad, Milbemycin

Medication reference facts with explicit FDA-approval, off-label, source-limited, and safety context. Roxee does not sell, prescribe, or dispense medications.

Both Reference complete FDA data linked Rx required Chewable Tablets Elanco US Inc. Official label facts Owner quick guide first
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Data freshness

Reference facts
Reference refreshed
Aug 6, 2026, 7:47 p.m.

These are the reference facts Roxee uses on browse cards and quick facts.

FDA applications
FDA application data refreshed
Aug 6, 2026, 7:47 p.m.

Sponsor, product, and application records imported from Animal Drugs @ FDA.

Safety reports
Safety data refreshed
Aug 6, 2026, 7:49 p.m.

openFDA reaction terms and case summaries are supporting evidence, not proof of causality.

Source timing details
Source timing details
  • Reference facts: Source Roxee | Refreshed Aug 6, 2026, 7:47 PM UTC
    The reference fact projection used for browse cards and quick facts.
  • Animal Drugs @ FDA: Source FDA | Refreshed Aug 6, 2026, 7:46 PM UTC
    Applications/products are imported from FDA export data.
  • Animal Drugs @ FDA previews: Source FDA | Refreshed Feb 9, 2026, 3:05 AM UTC
    Label highlights/doc links are fetched from FDA preview endpoints.
  • Animal Drug Product Listing Directory (NDC): Source FDA | Refreshed Aug 6, 2026, 7:47 PM UTC
    Package/product NDCs from FDA’s electronic listing directory (XLS).
  • openFDA reaction terms: Source FDA openFDA | Refreshed Aug 6, 2026, 7:52 PM UTC
  • openFDA case summaries: Source FDA openFDA | Refreshed Aug 6, 2026, 7:52 PM UTC
Illustration placeholder
Spinosad, Milbemycin

Spinosad, Milbemycin

Drug type: Generic ingredient • Branded profile • FDA branded products available

Both Chewable Tablets Rx required 100% reference complete

Species: Both

Manufacturer: Elanco US Inc.

Medication Snapshot

Merged from the current Roxee medication system with field-level provenance, freshness, and completeness tracking.

Spinosad, Milbemycin

Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatment of flea infestations ( Ctenocephalides felis ), and the treatment and control of adult hookworm ( Ancylostoma caninum ), adult roundworm ( Toxocara canis and Toxascaris leonina ) and adult whipworm ( Trichuris vulpis ) infections in dogs and puppies 8 weeks of age or older and 5 pounds of body weight or greater. Trifexis™Chewable Tablets are indicated for the prevention of heartworm disease ( Dirofilaria immitis ). Species commonly shown: Both, Dog.

Generic name
Spinosad, Milbemycin
Brand names
Trifexis™, Trifexis
Manufacturer
Elanco US Inc.
Species
Both, Dog
Dosage forms
Chewable Tablets
Prescription
Prescription required
Completeness
100%
Validation
Complete
Brand names
Trifexis™ Trifexis
Dosage forms
Chewable Tablets

Indications / Uses

Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatment of flea infestations ( Ctenocephalides felis ), and the treatment and control of adult hookworm ( Ancylostoma caninum ), adult roundworm ( Toxocara canis and Toxascaris leonina ) and adult whipworm ( Trichuris vulpis ) infections in dogs and puppies 8 weeks of age or older and 5 pounds of body weight or greater. Trifexis™Chewable Tablets are indicated for the prevention of heartworm disease ( Dirofilaria immitis ).

Warnings / Contraindications

Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.

  • Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.

Side Effects

Top reported reactions (openFDA): Lack of efficacy (endoparasite) - heartworm, Emesis (multiple), Lethargy (see also Central nervous system depression in 'Neurological'), Shaking, Sleepiness - systemic disorder, Vomiting.

FAQ

Both, Dog

Yes. Roxee shows this as prescription-only.

Chewable Tablets

Related Conditions

Fleas (Flea Infestation) Heartworm Disease

Source Transparency

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Pet Owner Quick Guide

Start here first for the safest next-step summary before the deeper medication detail.

Used for:

Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatment of flea infestations ( Ctenocephalides felis ), and the treatment and control of adult hookworm ( Ancylostoma caninum ), adult roun...

Dosing note:

Exact dosing depends on your pet's species, weight, and health status. Use your veterinarian's instructions for the exact dose and schedule.

What to watch for:

  • Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian
  • Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention
  • Use with caution in breeding females
  • The safe use of TRIFEXIS in breeding males has not been evaluated
  • Use with caution in dogs with pre-existing epilepsy
  • Walking difficulty (1 reports)
  • Vomiting (1 reports)
  • Urine abnormalities 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 tell or 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?

Next actions

Talk to a Vet / Find a Vet Near You Save to pet meds Share page Review report evidence
Research brief

Medication Research Insights

A source-aware map of what to know, what is uncertain, and what to verify with your veterinarian.

Source Backed Signals

What to know

Evidence-backed context Limited

Roxee has limited cited overview evidence for Spinosad, Milbemycin; use the official documents and your veterinarian's instructions for product-specific decisions.

Source: openFDA case USA-USFDACVM-2026-US-014359
Safety signal coverage Reported signals

32 tracked reaction signals; 32 reported cases; 22 serious reports; 1 species group. These are reporting and label-derived signals for interpretation with a veterinarian.

Source: openFDA case USA-USFDACVM-2026-US-014359
Interpretation guardrail Not causation

Adverse-event reports help form a watch list, but they do not prove the medication caused the reaction and they are not a risk ranking between medications.

Evidence tension

Stronger signal Label / review

Official labels, package inserts, and reviewed summaries carry more weight than isolated reports.

Source: openFDA case USA-USFDACVM-2026-US-014359
Weaker signal Reported data

Case reports and openFDA terms are useful for pattern awareness, but they are incomplete, can include multiple exposures, and do not estimate an individual pet's probability of harm.

Reaction signal map

Most reported reactions Top terms

Walking difficulty (1 reports), Vomiting (1 reports), Urine abnormalities NOS (1 reports), Swelling NOS (1 reports), Stumbling gait (1 reports)

Body systems represented Signal grouping

Digestive (1), Skin & allergy (1), Neurologic (2), Behavior (1)

Explore supporting adverse reports

Species and breed lens

Species represented in reports Species lens

Dog (32 reports)

Breed metadata in reports Metadata only

['Chihuahua', 'Dachshund (unspecified)'] (2), Bulldog - French (1), Shepherd Dog - German (1), Hound - Basset (1). These are report metadata, not proof that a breed is at higher risk.

What your vet may verify

Fit for this patient Vet check

Verify whether Spinosad, Milbemycin fits the pet's species, current diagnosis, age, weight, organ status, pregnancy/lactation status, and concurrent medications.

Evidence limitations Evidence review

Separate label-backed warnings from adverse-event reports and owner observations before changing the plan.

What to watch next

Watch list Owner-safe

Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian, Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide compl, Use with caution in breeding females, The safe use of TRIFEXIS in breeding males has not been evaluated, Use with caution in dogs with pre-existing epilepsy

Call sooner if Escalation

Repeated vomiting or diarrhea. Severe lethargy (hard to wake, very low energy). Collapse or fainting.

Bottom line: Use this Spinosad, Milbemycin brief as a structured watch list and source map, not as a reason to start, stop, or change treatment without your veterinarian.
Vet source depth
  1. openFDA case USA-USFDACVM-2026-US-014359 · adverse_reaction · adverse reactions
  2. Contraindication source · fda_animal_drugs · warnings contraindications
  3. FDA application profile · official_label · quick facts
  4. Medication usage source · fda_animal_drugs · quick facts
  5. FOI · document · documents
  6. Labeling · document · documents
  7. SPL · document · documents
  8. Structured Product Label · document · documents

Evidence

Review status / Updated / Sources

Review status: Clinical reviewer not listed

Updated: April 22, 2026, 10:06 AM UTC

Sources:
Safety & side effects

Side effects to monitor:

  • Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian
  • Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention
  • Use with caution in breeding females
  • The safe use of TRIFEXIS in breeding males has not been evaluated
  • Use with caution in dogs with pre-existing epilepsy

Most reported reactions:

  • Walking difficulty (1 reports)
  • Vomiting (1 reports)
  • Urine abnormalities NOS (1 reports)
Explore reported case details

Emergency warning signs:

  • 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

Vet Fast Scan

Source-backed clinical checkpoints for quick review.

FDA-labeled species
Dog
Indication / use
Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatment of flea infestations ( Ctenocephalides felis ), and the treatment and control of adult hoo…
Form / route / dose
Form: Chewable Tablets
Route: Oral
Confirm product label and patient-specific plan.
Warnings
  • High: Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3…
Adverse-event caveat
openFDA adverse-event cases are reported signals. They are not verified, do not prove causation, and do not estimate a pet's individual risk.
Source docs

Quick Facts

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

Species: Both
Manufacturer: Elanco US Inc.
Form: Chewable Tablets
Identifiers:
NADA: 141321 NDC Package: 58198-0042-1 NDC Package: 58198-0042-6 NDC Package: 58198-0043-1 NDC Package: 58198-0043-6 NDC Package: 58198-0044-1 NDC Package: 58198-0044-6 NDC Package: 58198-0045-1 NDC Package: 58198-0045-6 NDC Package: 58198-0046-1 NDC Package: 58198-0046-6 NDC Product: 58198
Source metadata:

Warnings / Contraindications

Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.

  • High: Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.
Source metadata:

Adverse Reactions

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

Reported case explorer

Filter stored openFDA reports by pet and report attributes. Counts describe reports in this data set, not risk.

Clear filters
openFDA adverse-event cases are reported signals. They are not verified, do not prove causation, and do not estimate a pet's individual risk.
Stored reports
12
Matching reports
0
Active filters
2
Selected filters
Reaction: UNPALATABLE Clear Body system: Effectiveness Clear
Reset
Drill into common report signals
Lack of efficacy (endoparasite) - heartworm (5) Vomiting (4) Lethargy (see also Central nervous system depression in Neurological) (3) UNPALATABLE (3) Other (7) Effectiveness (6) Digestive (4) Neurologic (4)
No stored openFDA reports match the selected filters. openFDA adverse-event cases are reported signals. They are not verified, do not prove causation, and do not estimate a pet's individual risk.

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

Tracked signals
32
Reported cases
32
Serious reports
22
Species represented
1
Grouped by Body System
Digestive (1) · Vomiting Skin & allergy (1) · Swelling NOS Neurologic (2) · Tiredness (lethargy), Seizure NOS Behavior (1) · Behavioral disorder (unspecified) Effectiveness (2) · Lack of efficacy (endoparasite) - heartworm, Lack of efficacy (ectoparasite) - flea Other (25) · Walking difficulty, Urine abnormalities NOS, UNPALATABLE
Most Reported Reactions
Reaction Body system Cases Species Serious cases
Other 1 Dog 1
Digestive 1 Dog 1
Other 1 Dog 1
Skin & allergy 1 Dog 1
Other 1 Dog 1
Neurologic 1 Dog 1
Other 1 Dog 1
Other 1 Dog 1

Species coverage: Dog (32)

View detailed reaction table
Reaction Body system Species Seriousness Frequency Reports
Other Dog Serious - 1
Digestive Dog Serious - 1
Other Dog Serious - 1
Other Dog Non-serious - 1
Neurologic Dog Non-serious - 1
Skin & allergy Dog Serious - 1
Other Dog Serious - 1
Other Dog Non-serious - 1
Neurologic Dog Serious - 1
Other Dog Serious - 1
Other Dog Non-serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Effectiveness Dog Non-serious - 1
Effectiveness Dog Non-serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Non-serious - 1
Other Dog Non-serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Behavior Dog Non-serious - 1
Other Dog Non-serious - 1
Other Dog Serious - 1
Source metadata:

Source Documents

The most useful source links appear first; full previews and metadata stay in the veterinary/professional layer.

Use original documents to confirm product-specific warnings, ingredients, and handling details with your veterinarian.

TRIFEXIS N141321C0060.pdf Official label / PI · Labeling Trifexis™ SPL · SPL Trifexis SPL SPL · Structured Product Label

Full source previews and metadata remain in the veterinary/professional layer.

Owner handouts

0
No owner handouts linked yet.

Official label / PI

1

SPL

2

FOI

1

TRIFEXIS N141321C0060.pdf

Official label / PI · Labeling

Open original

Trifexis™

SPL · SPL

Open original
FDA Structured Product Label

Trifexis™

Rendered from Roxee's cached FDA SPL package contents for on-page reading. Use Open original for the raw FDA ZIP/XML source.

Sponsor
Elanco US Inc.
NADA
141-321
Status
RX
Form
Chewable Tablets
Route
Oral
Species
Dog
Composition / specifications
The product is available in five tablet strengths:
140 mg spinosad and 2.3 mg milbemycin oxime
270 mg spinosad and 4.5 mg milbemycin oxime
560 mg spinosad and 9.3 mg milbemycin oxime
810 mg spinosad and 13.5 mg milbemycin oxime
1620 mg spinosad and 27 mg milbemycin oxime

Dogs and Puppies (8 Weeks and Older and 5 Lbs or Greater)

Indication
Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatment of flea infestations (Ctenocephalides felis), and the treatment and control of adult hookworm (Ancylostoma caninum), adult roundworm (Toxocara canis and Toxascaris leonina) and adult whipworm (Trichuris vulpis) infections in dogs and puppies 8 weeks of age or older and 5 pounds of body weight or greater.
Dosage
Given orally, once a month at a minimum dosage of 13.5 mg/lb (30 mg/kg) spinosad and 0.2 mg/lb (0.5 mg/kg) milbemycin oxime body weight.
Limitations
Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.
Indication
Trifexis™Chewable Tablets are indicated for the prevention of heartworm disease (Dirofilaria immitis).
Dosage
Given orally, once a month at a minimum dosage of 13.5 mg/lb (30 mg/kg) spinosad and 0.2 mg/lb (0.5 mg/kg) milbemycin oxime body weight.
Limitations
Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.

Trifexis SPL

SPL · Structured Product Label

Open original
FDA Structured Product Label XML for Trifexis. Use the source link for the full official labeling record.

UCM252248.pdf

FOI · FOI

Open original
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
  • Reference facts: Source Roxee | Refreshed Aug 6, 2026, 7:47 PM UTC
    The reference fact projection used for browse cards and quick facts.
  • Animal Drugs @ FDA: Source FDA | Refreshed Aug 6, 2026, 7:46 PM UTC
    Applications/products are imported from FDA export data.
  • Animal Drugs @ FDA previews: Source FDA | Refreshed Feb 9, 2026, 3:05 AM UTC
    Label highlights/doc links are fetched from FDA preview endpoints.
  • Animal Drug Product Listing Directory (NDC): Source FDA | Refreshed Aug 6, 2026, 7:47 PM UTC
    Package/product NDCs from FDA’s electronic listing directory (XLS).
  • openFDA reaction terms: Source FDA openFDA | Refreshed Aug 6, 2026, 7:52 PM UTC
  • openFDA case summaries: Source FDA openFDA | Refreshed Aug 6, 2026, 7:52 PM UTC
Official (FDA)
Identity: Generic ingredient • FDA branded products available
Official FDA brands: Trifexis
Manufacturer mapping: Elanco US Inc.
Case-reported brands (openFDA): MSK
Catalog species: Both • FDA-labeled species: Dog
Rx/OTC: RX
Form/route: Chewable Tablets • Oral
Applications: NADA 141-321
NDC: Packages 58198-0042-1 58198-0042-6 58198-0043-1 58198-0043-6 58198-0044-1 58198-0044-6 • Products 58198
Documents: 2 (FOI: 1) • SPL: 1 • Label highlights • Official documents
Safety (openFDA)
Top reactions: Dog 33 • Cat 0 • View
Case summaries: 12 (showing 8) • View
openFDA reports are unverified and do not prove causation.
Explore
Linked using: Fda_Label (0.95), Fda_Label (0.95)
Diagnosis Codes
ICD10_CM: B74.8 ICD10_CM: B88.1
Other filariases

Counseling and Monitoring Highlights

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

Owner-facing counseling points
  • Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy. (Contraindication, High)
Top reaction signals
Walking difficulty (1) Vomiting (1) Urine abnormalities NOS (1) Swelling NOS (1) Stumbling gait (1) Seizure NOS (1) Proprioception deficit (1) Other abnormal test result NOS (1)

Identifiers & Packages

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

Identifiers
NADA: 141321 NDC Package: 58198-0042-1 NDC Package: 58198-0042-6 NDC Package: 58198-0043-1 NDC Package: 58198-0043-6 NDC Package: 58198-0044-1 NDC Package: 58198-0044-6 NDC Package: 58198-0045-1 NDC Package: 58198-0045-6 NDC Package: 58198-0046-1 NDC Package: 58198-0046-6 NDC Product: 58198
Package NDC Product NDC Form / Route Status
58198-0042-1 58198 -
58198-0042-6 58198 -
58198-0043-1 58198 -
58198-0043-6 58198 -
58198-0044-1 58198 -
58198-0044-6 58198 -
58198-0045-1 58198 -
58198-0045-6 58198 -
58198-0046-1 58198 -
58198-0046-6 58198 -

Enriched Documents

Documents are tiered by source trust: Official, Clinical, Manufacturer, Marketing.

  • Trifexis SPL • Structured Product Label • Official
    FDA Structured Product Label from the electronic animal drug product listing directory.
  • TRIFEXIS N141321C0060.pdf • Official label • Official • May 17, 2021
    FDA official labeling for application 141321
  • UCM252248.pdf • FOI summary • Official • May 17, 2021
    FDA FOI summary for application 141321

Data Sources & Change Log

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

Official 121 Clinical 2 Manufacturer 0 Marketing 0
Current Field Facts
  • side_effects: Top reported reactions (openFDA): Lack of efficacy (endoparasite) - heartworm, Emesis (multiple), Lethargy (see also Central nervous system depression in 'Neur… (Clinical, 2026-04-15)
  • side_effects: Top reported reactions (openFDA): Lack of efficacy (endoparasite) - heartworm, Emesis (multiple), Lethargy (see also Central nervous system depression in 'Neur… (Clinical, 2026-04-11)
  • contraindications: Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure t… (Official, 2026-04-22)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-08-06)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-08-05)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-08-04)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-08-03)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-08-02)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-08-01)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-31)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-30)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-29)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-28)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-27)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-26)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-25)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-25)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-22)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-22)
  • indications: Indicated for the prevention of heartworm disease ( Dirofilaria immitis). Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatm… (Official, 2026-07-22)
Recent Revisions
  • side_effects updated 2026-04-22 10:07 by etl_backfill • Backfilled from existing medication fields
  • contraindications updated 2026-04-22 10:07 by etl_backfill • Backfilled from existing medication fields
  • usage updated 2026-04-22 10:07 by etl_backfill • Backfilled from existing medication fields
  • side_effects updated 2026-04-15 10:04 by etl_backfill • Backfilled from existing medication fields
  • side_effects updated 2026-04-11 10:05 by etl_backfill • Backfilled from existing medication fields
  • side_effects updated 2026-02-12 22:44 by etl_backfill • Backfilled from existing medication fields

FDA Products & Applications (Animal Drugs @ FDA)

Official sponsor/proprietary-name/application-status records linked by active ingredient.

Product Sponsor Application Status Published
Trifexis™
RX
Milbemycin Oxime Spinosad
Chewable Tablets • Oral
Label highlights
Official documents
Elanco US Inc. NADA 141-321 Approved May 17, 2021

Data source: FDA Animal Drugs @ FDA (public search export).

What It's For (FDA Label Highlights)

Extracted from FDA Animal Drugs @ FDA product labeling. Always confirm details with your veterinarian.

Species: Dog
Composition / specifications
The product is available in five tablet strengths:
140 mg spinosad and 2.3 mg milbemycin oxime
270 mg spinosad and 4.5 mg milbemycin oxime
560 mg spinosad and 9.3 mg milbemycin oxime
810 mg spinosad and 13.5 mg milbemycin oxime
1620 mg spinosad and 27 mg milbemycin oxime
Dogs and Puppies (8 Weeks and Older and 5 Lbs or Greater)
Indication
Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatment of flea infestations (Ctenocephalides felis), and the treatment and control of adult hookworm (Ancylostoma caninum), adult roundworm (Toxocara canis and Toxascaris leonina) and adult whipworm (Trichuris vulpis) infections in dogs and puppies 8 weeks of age or older and 5 pounds of body weight or greater.
Dosage
Given orally, once a month at a minimum dosage of 13.5 mg/lb (30 mg/kg) spinosad and 0.2 mg/lb (0.5 mg/kg) milbemycin oxime body weight.
Limitations
Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.
Indication
Trifexis™Chewable Tablets are indicated for the prevention of heartworm disease (Dirofilaria immitis).
Dosage
Given orally, once a month at a minimum dosage of 13.5 mg/lb (30 mg/kg) spinosad and 0.2 mg/lb (0.5 mg/kg) milbemycin oxime body weight.
Limitations
Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.

FDA page: Open in Animal Drugs @ FDA

Usage

Trifexis™ Chewable Tablets kill fleas and are indicated for the prevention and treatment of flea infestations ( Ctenocephalides felis ), and the treatment and control of adult hookworm ( Ancylostoma caninum ), adult roundworm ( Toxocara canis and Toxascaris leonina ) and adult whipworm ( Trichuris vulpis ) infections in dogs and puppies 8 weeks of age or older and 5 pounds of body weight or greater. Trifexis™Chewable Tablets are indicated for the prevention of heartworm disease ( Dirofilaria immitis ).

Source: FDA Animal Drugs @ FDA • Reference

Contraindications

Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Treatment with fewer than 3 monthly doses after the last exposure to mosquitos may not provide complete heartworm prevention. Use with caution in breeding females. The safe use of TRIFEXIS in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy.

Top Reported Reactions (openFDA)

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

Digestive
Vomiting (1) • Dog

Showing top 5 for Digestive.

Skin & allergy
Swelling NOS (1) • Dog

Showing top 5 for Skin & allergy.

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

Showing top 5 for Neurologic.

Behavior
Behavioral disorder (1) • Dog

Showing top 5 for Behavior.

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

Showing top 5 for Effectiveness.

Other
Walking difficulty (1) • Dog Urine abnormalities NOS (1) • Dog UNPALATABLE (1) • Dog Stumbling gait (1) • Dog Shaking (1) • Dog
Show more (20)
Proprioception deficit (1) • Dog Overdose (1) • Dog Other abnormal test result NOS (1) • Dog Not himself/herself (1) • Dog Not eating (1) • Dog Neutrophilia (1) • Dog Increased lung sounds (1) • Dog Hypokalaemia (1) • Dog Haemolytic anaemia (1) • Dog Falling (1) • Dog Difficulty standing (1) • Dog Decreased red blood cell count (1) • Dog Decreased percentage of reticulocytes (1) • Dog Death by euthanasia (1) • Dog Cough (1) • Dog Corneal opacity (1) • Dog Cloudy eye (1) • Dog Blood in urine (1) • Dog Accidental exposure (1) • Dog Abnormal breathing (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, ['Chihuahua', 'Dachshund (unspecified)'], Male, 11 month, 5.9 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal, Frequency: 1 per month • Reactions: Lack of efficacy (endoparasite) - heartworm • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2026-US-014250
  • Serious AE: No
  • Treated For AE: No
  • Sex: Male
  • Age: 11.00 Month
  • Weight: 5.900 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
  • Frequency: 1 per month
Reactions Reported:
Lack of efficacy (endoparasite) - heartworm
Outcomes: Outcome Unknown

Dog, Bulldog - French, Male, 10 month, 8.2 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal, Frequency: 1 per month • Reactions: Lack of efficacy (ectoparasite) - flea • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2026-US-014245
  • Serious AE: No
  • Treated For AE: Yes
  • Sex: Male
  • Age: 10.00 Month
  • Weight: 8.200 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
  • Frequency: 1 per month
Reactions Reported:
Lack of efficacy (ectoparasite) - flea
Outcomes: Outcome Unknown

Dog, Shepherd Dog - German, Male, 9 year, 32.56 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal, Frequency: 1 per month • Reactions: Lack of efficacy (endoparasite) - heartworm • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2026-US-012586
  • Serious AE: No
  • Treated For AE: No
  • Sex: Male
  • Age: 9.00 Year
  • Weight: 32.560 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
  • Frequency: 1 per month
Reactions Reported:
Lack of efficacy (endoparasite) - heartworm
Outcomes: Outcome Unknown

Dog, Hound - Basset, Female, 7 year, 18.597 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal, Frequency: 1 per month • Reactions: Stumbling gait, Not eating, Seizure NOS, Neutrophilia, Proprioception deficit… • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2026-US-014094
  • Serious AE: Yes
  • Treated For AE: Yes
  • Sex: Female
  • Age: 7.00 Year
  • Weight: 18.597 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
  • Frequency: 1 per month
Reactions Reported:
Stumbling gait Not eating Seizure NOS Neutrophilia Proprioception deficit Not himself/herself Hypokalaemia
Outcomes: Outcome Unknown

Dog, Retriever - Labrador, Male, 1 year, 37.82 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal • Reactions: Lack of efficacy (endoparasite) - heartworm • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2026-US-013254
  • Serious AE: No
  • Treated For AE: No
  • Sex: Male
  • Age: 1.00 Year
  • Weight: 37.820 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
Reactions Reported:
Lack of efficacy (endoparasite) - heartworm
Outcomes: Outcome Unknown

Dog, ['Siberian Husky', 'Shepherd Dog - German'], Male, 9 year, 41.277 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal, Frequency: 1 per day • Reactions: Other abnormal test result NOS, Lack of efficacy (endoparasite) - heartworm, Tiredness (lethargy), Death by euthanasia, Blood in urine… • Outcome: Euthanized

  • Report ID: USA-USFDACVM-2026-US-014359
  • Serious AE: Yes
  • Treated For AE: Yes
  • Sex: Male
  • Age: 9.00 Year
  • Weight: 41.277 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
  • Frequency: 1 per day
Reactions Reported:
Other abnormal test result NOS Lack of efficacy (endoparasite) - heartworm Tiredness (lethargy) Death by euthanasia Blood in urine Cloudy eye Cough Swelling NOS Corneal opacity Urine abnormalities NOS Weakness Increased lung sounds Haemolytic anaemia Not eating Abnormal breathing Walking difficulty Decreased red blood cell count Decreased percentage of reticulocytes
Outcomes: Euthanized

Dog, Doberman Pinscher, Female, 9 year, 27.21 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal • Reactions: Vomiting, UNPALATABLE • Outcome: Recovered/Normal

  • Report ID: USA-USFDACVM-2026-US-009736
  • Serious AE: No
  • Treated For AE: No
  • Sex: Female
  • Age: 9.00 Year
  • Weight: 27.210 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
Reactions Reported:
Vomiting UNPALATABLE
Outcomes: Recovered/Normal

Dog, ['Chihuahua', 'Dachshund (unspecified)'], Male, 7 year, 9.072 kilogram • Drug: MSK, Tablet, chewable, Oral, Dose: 1 tablet per animal • Reactions: Behavioral disorder (unspecified), UNPALATABLE • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-074717
  • Serious AE: No
  • Treated For AE: No
  • Sex: Male
  • Age: 7.00 Year
  • Weight: 9.072 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Dose: 1 tablet per animal
Reactions Reported:
Behavioral disorder (unspecified) UNPALATABLE
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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