Skip to main content
Start triage

Start triage first, then route to emergency care.

Start symptom intake Emergency vets near you

Need urgent help? Start triage first, then route to emergency care.

Start symptom intake Emergency vets near you

Meds A-Z

Heartworm Prevention

Detailed information about Heartworm Prevention

Official label facts Owner quick guide first Marketing clearly labeled
Talk to a Vet / Find a Vet Near You Start Symptom Intake

Veterinary professional?

Showing simplified owner view. Switch to Vet View for full technical detail.

Add to My Pet's Meds

Choose a pet, confirm current or past, and optionally add reminder notes.

Sign in to save this medication to your pet profile.

Sign in to continue

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:

  • wobbly/unsteady walking (1 reports)
  • very low energy (1 reports)
  • Stroke (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:

  • wobbly/unsteady walking
  • very low energy
  • Stroke

Most reported reactions:

  • Unsteady walking (ataxia) (1 reports)
  • Tiredness (lethargy) (1 reports)
  • Stroke (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 Feb 9, 2026, 3:15 AM UTC
  • openFDA case summaries: Source FDA openFDA | Refreshed Feb 9, 2026, 3:22 AM UTC
Image coming soon
Heartworm Prevention

Heartworm Prevention

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
27
Reported cases
22
Serious reports
22
Species represented
1
Grouped by Body System
Digestive (1) · Vomiting Neurologic (3) · Unsteady walking (ataxia), Tiredness (lethargy), Lethargy (see also Central nervous system depression in 'Neurological') Behavior (1) · Behavioral disorder (unspecified) Effectiveness (1) · Lack of efficacy (endoparasite) - heartworm Other (21) · Stroke, Splenic neoplasm NOS, Skin lesion NOS
Most Reported Reactions
Reaction Body system Cases Species Serious cases
Neurologic 1 Dog 1
Neurologic 1 Dog 1
Other 1 Dog 1
Other 1 Dog 1
Other 1 Dog 1
Other 1 Dog 1
Other 1 Dog 1
Other 1 Dog 1

Species coverage: Dog (27)

View detailed reaction table
Reaction Body system Species Seriousness Frequency Reports
Neurologic Dog Serious - 1
Neurologic 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
Other Dog Serious - 1
Effectiveness 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
Other Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Behavior Dog Serious - 1
Other Dog Serious - 1
Other Dog Serious - 1
Digestive Dog Unknown - -
Neurologic Dog Unknown - -
Other Dog Unknown - -
Other Dog Unknown - -
Other Dog 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 Feb 9, 2026, 3:15 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 8 • Cat 0 • View
Case summaries: 5 (showing 5) • 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
Unsteady walking (ataxia) (1) Tiredness (lethargy) (1) Stroke (1) Splenic neoplasm NOS (1) Skin lesion NOS (1) Scale (1) Not sleeping (1) Not eating (1)

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): Vomiting, Lack of efficacy (endoparasite) - heartworm, Lethargy (see also Central nervous system depression in 'Neurological'… (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
Vomiting • Dog

Showing top 5 for Digestive.

Neurologic
Unsteady walking (1) • Dog Tiredness (1) • Dog Tiredness (lethargy) • Dog

Showing top 5 for Neurologic.

Behavior
Behavioral disorder (1) • Dog

Showing top 5 for Behavior.

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

Showing top 5 for Effectiveness.

Other
Stroke (1) • Dog Splenic neoplasm NOS (1) • Dog Skin lesion NOS (1) • Dog Scale (1) • Dog Not sleeping (1) • Dog
Show more (16)
Not eating (1) • Dog Liver tumour (1) • Dog Knuckling (1) • Dog Haemorrhage NOS (1) • Dog Greasy skin (1) • Dog Fever (1) • Dog Discoloured urine (1) • Dog Death by euthanasia (1) • Dog Cyanotic spots/blotchy skin (1) • Dog Crust (1) • Dog Blindness (1) • Dog Anaemia NOS (1) • Dog Abnormal breathing (1) • Dog Elevated serum alkaline phosphatase • Dog Elevated alanine aminotransferase • Dog Adrenal gland disorder NOS • 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 (unspecified), Male, 14 year, 10.795 kilogram • Drug: MSK, Tablet, chewable, Oral, Frequency: 1 per month • Reactions: Lack of efficacy (endoparasite) - heartworm • Outcome: Ongoing

  • Report ID: USA-USFDACVM-2025-US-042677
  • Serious AE: Yes
  • Treated For AE: Yes
  • Sex: Male
  • Age: 14.00 Year
  • Weight: 10.795 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet, chewable
  • Frequency: 1 per month
Reactions Reported:
Lack of efficacy (endoparasite) - heartworm
Outcomes: Ongoing

Dog, Shepherd Dog - German, Female, 10 year, 43.091 kilogram • Drug: MSK, Tablet, Oral • Reactions: Cyanotic spots/blotchy skin, Discoloured urine, Splenic neoplasm NOS, Behavioral disorder (unspecified), Tiredness (lethargy)… • Outcome: Euthanized

  • Report ID: USA-USFDACVM-2025-US-039319
  • Serious AE: Yes
  • Treated For AE: Yes
  • Sex: Female
  • Age: 10.00 Year
  • Weight: 43.091 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Form: Tablet
Reactions Reported:
Cyanotic spots/blotchy skin Discoloured urine Splenic neoplasm NOS Behavioral disorder (unspecified) Tiredness (lethargy) Not eating Abnormal breathing Anaemia NOS Not sleeping Haemorrhage NOS Liver tumour Death by euthanasia
Outcomes: Euthanized

Dog, Maltese, Female, 14.5 year, 4.8 kilogram • Drug: MSK, Oral, Frequency: 1 per month • Reactions: Skin lesion NOS, Crust, Greasy skin, Scale • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-017337
  • Serious AE: Yes
  • Treated For AE: Yes
  • Sex: Female
  • Age: 14.50 Year
  • Weight: 4.800 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Oral
  • Frequency: 1 per month
Reactions Reported:
Skin lesion NOS Crust Greasy skin Scale
Outcomes: Outcome Unknown

Dog, Retriever - Labrador, Female, 21 month, 27.805 kilogram • Drug: MSK, Unknown • Reactions: Lack of efficacy (endoparasite) - heartworm • Outcome: Outcome Unknown

  • Report ID: USA-USFDACVM-2025-US-013465
  • Serious AE: No
  • Treated For AE: No
  • Sex: Female
  • Age: 21.00 Month
  • Weight: 27.805 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Unknown
Reactions Reported:
Lack of efficacy (endoparasite) - heartworm
Outcomes: Outcome Unknown

Dog, Shepherd Dog - Australian, Female, 11 year, 14.061 kilogram • Drug: MSK, Unassigned, Unknown • Reactions: Fever, Knuckling, Unsteady walking (ataxia), Blindness, Stroke… • Outcome: Euthanized

  • Report ID: USA-USFDACVM-2025-US-006550
  • Serious AE: Yes
  • Treated For AE: Yes
  • Sex: Female
  • Age: 11.00 Year
  • Weight: 14.061 Kilogram
  • Case-reported brand: MSK
  • Case-reported manufacturer: MSK
  • Route: Unknown
  • Form: Unassigned
Reactions Reported:
Fever Knuckling Unsteady walking (ataxia) Blindness Stroke Death by euthanasia
Outcomes: Euthanized

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.

Share Your Thoughts

Let others know your experience or advice regarding this medication.

This medication has not been reviewed by a veterinarian yet.