Meds A-Z

Levothyroxine Sodium

Detailed information about Levothyroxine Sodium

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.

Reviewed / Updated / Sources

Reviewed: Not available

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

Sources:

FDA application profile · official_label
FDA application profile · official_label
Medication usage source · fda_animal_drugs
openFDA case USA-USFDACVM-2025-US-055162 · adverse_reaction
FOI · document

Pet Owner Quick Guide

Start here first for the simple next-step summary.

Used for:

For replacement therapy for diminished thyroid function in dogs.

What to watch for:

For oral use in dogs only
very low energy (1 reports)
Leucocytosis NOS (1 reports)
Hair loss (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.

Regulatory restrictions are shown in Vet View.

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:

For oral use in dogs only
very low energy
Leucocytosis NOS
Hair loss

Most reported reactions:

Tiredness (lethargy) (1 reports)
Leucocytosis NOS (1 reports)
Hair loss (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 Drugs @ FDA: Source FDA | Refreshed Mar 21, 2026, 10:00 AM 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 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 15, 2026, 10:05 AM UTC
openFDA case summaries: Source FDA openFDA | Refreshed Feb 9, 2026, 3:21 AM UTC

Image coming soon

Levothyroxine Sodium

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

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

Form: Tablet

Identifiers:

NADA: 141448 NADA: 141539 NDC Package: 11695-6957-1 NDC Package: 11695-6957-2 NDC Package: 11695-6958-1 NDC Package: 11695-6958-2 NDC Package: 11695-6959-1 NDC Package: 11695-6959-2 NDC Package: 11695-6960-1 NDC Package: 11695-6960-2 NDC Package: 11695-6961-1 NDC Package: 11695-6961-2 NDC Package: 11695-6962-1 NDC Package: 11695-6962-2 NDC Package: 11695-6963-1 NDC Package: 11695-6963-2 NDC Package: 11695-6964-1 NDC Package: 11695-6964-2 NDC Package: 11695-6965-1 NDC Package: 11695-6965-2

Source metadata:

https://animaldrugsatfda.fda.gov/adafda/views/#/home/previewsearch/141539 · official_label · FDA application profile
https://animaldrugsatfda.fda.gov/adafda/views/#/home/previewsearch/141448 · official_label · FDA application profile
https://animaldrugsatfda.fda.gov · fda_animal_drugs · Medication usage source

Warnings / Contraindications

For oral use in dogs only. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

High: For oral use in dogs only. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Source metadata:

https://animaldrugsatfda.fda.gov · fda_animal_drugs · Contraindication source

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

Reported cases

Serious reports

Species represented

Grouped by Body System

Digestive (3) · Drooling, Diarrhea, Decreased appetite Skin & allergy (1) · Hair loss Neurologic (1) · Tiredness (lethargy) Effectiveness (3) · Lack of efficacy - NOS, Lack of efficacy (endoparasite) - hookworm, Lack of efficacy Other (24) · Oliguria, Not himself/herself, Not defecating

Most Reported Reactions

Body system	Cases	Species	Serious cases
Neurologic	1	Dog	1
Other	1	Cat	1
Skin & allergy	1	Dog	1
Other	1	Dog	1
Other	1	Dog	1
Other	1	Cat	1
Other	1	Cat	1
Digestive	1	Dog	1

Species coverage: Dog (18) Cat (14)

View detailed reaction table

Body system	Species	Seriousness	Frequency	Reports
Neurologic	Dog	Serious	-	1
Other	Dog	Non-serious	-	1
Other	Cat	Non-serious	-	1
Other	Dog	Non-serious	-	1
Other	Cat	Non-serious	-	1
Other	Cat	Serious	-	1
Effectiveness	Dog	Non-serious	-	1
Effectiveness	Dog	Non-serious	-	1
Effectiveness	Cat	Non-serious	-	1
Other	Cat	Non-serious	-	1
Skin & allergy	Dog	Serious	-	1
Other	Dog	Non-serious	-	1
Other	Dog	Serious	-	1
Other	Dog	Serious	-	1
Other	Cat	Non-serious	-	1
Other	Dog	Non-serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Digestive	Cat	Non-serious	-	1
Other	Cat	Non-serious	-	1
Digestive	Dog	Serious	-	1
Other	Dog	Non-serious	-	1
Other	Dog	Non-serious	-	1
Digestive	Dog	Non-serious	-	1
Other	Dog	Non-serious	-	1
Other	Cat	Non-serious	-	1
Other	Dog	Serious	-	1
Other	Dog	Non-serious	-	1
Other	Cat	Non-serious	-	1
Other	Cat	Non-serious	-	1
Other	Cat	Serious	-	1
Other	Dog	Serious	-	1

Source metadata:

https://api.fda.gov/animalandveterinary/event.json · adverse_reaction · openFDA case USA-USFDACVM-2025-US-055162

Documents

Owner handouts and official technical documents are grouped for faster access.

Owner handouts (0)

No owner handouts linked yet.

Official label / PI (0)

No official label or package insert links yet.

SPL (2)

ThyroKare™ · SPL
https://animaldrugsatfda.fda.gov/adafda/app/search/public/spl/file/10370/ThyroKare%E2%84%A2
Thyro-Tabs® Canine · SPL
https://animaldrugsatfda.fda.gov/adafda/app/search/public/spl/file/2392/Thyro-Tabs%C2%AE%20Canine

FOI (2)

FOI Summary oN 141-539 Approved January 15, 2021.pdf · FOI
https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/10310
UCM484490.pdf · FOI
https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/937

Source metadata:

https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/10310 · document · FOI
https://animaldrugsatfda.fda.gov/adafda/app/search/public/spl/file/10370/ThyroKare%E2%84%A2 · document · SPL
https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/937 · document · FOI
https://animaldrugsatfda.fda.gov/adafda/app/search/public/spl/file/2392/Thyro-Tabs%C2%AE%20Canine · document · SPL

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 Drugs @ FDA: Source FDA | Refreshed Mar 21, 2026, 10:00 AM 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 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 15, 2026, 10:05 AM UTC
openFDA case summaries: Source FDA openFDA | Refreshed Feb 9, 2026, 3:21 AM UTC

Official (FDA)

Identity: Generic ingredient • FDA branded products available

Official FDA brands: Thyro-Tabs® Canine ThyroKare™

Case-reported brands (openFDA): MSK

Catalog species: Both • FDA-labeled species: Dog

Rx/OTC: RX

Form/route: Tablet • Oral

Applications: NADA 141-539 • NADA 141-448

Documents: 2 (FOI: 2) • SPL: 2 • Label highlights • Official documents

Safety (openFDA)

Top reactions: Dog 18 • 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.

Owner-facing counseling points

For oral use in dogs only. Federal law restricts this drug to use by or on the order of a licensed veterinarian. (Contraindication, High)

Top reaction signals

Tiredness (lethargy) (1) Leucocytosis NOS (1) Hair loss (1) Excoriation (1) Erythema (1) Elevated blood urea nitrogen (1) Elevated amylase (1) Diarrhea (1)

Identifiers & Packages

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

Identifiers

Package NDC	Product NDC	Status
11695-6957-1	11695	-
11695-6957-2	11695	-
11695-6958-1	11695	-
11695-6958-2	11695	-
11695-6959-1	11695	-
11695-6959-2	11695	-
11695-6960-1	11695	-
11695-6960-2	11695	-
11695-6961-1	11695	-
11695-6961-2	11695	-
11695-6962-1	11695	-
11695-6962-2	11695	-
11695-6963-1	11695	-
11695-6963-2	11695	-
11695-6964-1	11695	-
11695-6964-2	11695	-
11695-6965-1	11695	-
11695-6965-2	11695	-
11695-7014-1	11695	-
11695-7014-2	11695	-

Enriched Documents

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

FOI Summary oN 141-539 Approved January 15, 2021.pdf • FOI summary • Official • Feb. 1, 2021
FDA FOI summary for application 141539
UCM484490.pdf • FOI summary • Official • June 1, 2016
FDA FOI summary for application 141448

Data Sources & Change Log

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

Official 5 Clinical 0 Manufacturer 0 Marketing 0

Current Field Facts

contraindications: For oral use in dogs only. Federal law restricts this drug to use by or on the order of a licensed veterinarian. (Official, 2026-02-12)
side_effects: Top reported reactions (openFDA): Overdose, Vomiting, Diarrhoea, Lethargy (see also Central nervous system depression in 'Neurological'), Panting, Lack of effi… (Official, 2026-02-12)
usage: For replacement therapy for diminished thyroid function in dogs. (Official, 2026-02-12)

Recent Revisions

side_effects updated 2026-02-12 22:44 by etl_backfill • Backfilled from existing medication fields
contraindications updated 2026-02-12 22:44 by etl_backfill • Backfilled from existing medication fields
usage 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
ThyroKare™ RX Levothyroxine sodium Tablet • Oral Label highlights Official documents	Neogen Corp.	NADA 141-539	Approved	Feb 1, 2021
Thyro-Tabs® Canine RX Levothyroxine sodium Tablet • Oral Label highlights Official documents	Lloyd, Inc.	NADA 141-448	Approved	Jun 1, 2016

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, No Use Class Stated Or Implied

Composition / specifications

0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, or 1.0 mg of levothyroxine sodium per tablet

Dogs

Indication

For replacement therapy for diminished thyroid function in dogs.

Dosage

The initial dose is 0.1 mg/10 lb (0.01 mg/lb, 0.022 mg/kg) body weight twice daily.

Limitations

FDA page: Open in Animal Drugs @ FDA

Species: Dog, No Use Class Stated Or Implied

Composition / specifications

0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, or 1.0 mg of levothyroxine sodium per tablet

Dogs

Indication

For replacement therapy for diminished thyroid function in dogs.

Dosage

Administer by mouth 0.1 mg/10 pounds of body weight (0.022 mg/kilogram) as a single dose every 24 hours or as a divided dose every 12 hours.

Limitations

For oral use in dogs only. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

FDA page: Open in Animal Drugs @ FDA

Official Documents (FDA)

Direct links to FDA-hosted PDFs and SPL packages (when available).

Documents

FOI FOI Summary oN 141-539 Approved January 15, 2021.pdf

Summary

For replacement therapy for diminished thyroid function in dogs.

SPL Packages

ThyroKare™ (ZIP)

FDA page: Open in Animal Drugs @ FDA

Documents

FOI UCM484490.pdf

Summary

For replacement therapy for diminished thyroid function in dogs.

SPL Packages

Thyro-Tabs® Canine (ZIP)

FDA page: Open in Animal Drugs @ FDA

Usage

For replacement therapy for diminished thyroid function in dogs.

Source: FDA Animal Drugs @ FDA • Reference

Contraindications

For oral use in dogs only. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Top Reported Reactions (openFDA)

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

Digestive

Drooling (1) • Cat Diarrhea (1) • Dog Decreased appetite (1) • Dog

Showing top 5 for Digestive.

Skin & allergy

Hair loss (1) • Dog

Showing top 5 for Skin & allergy.

Neurologic

Tiredness (1) • Dog

Showing top 5 for Neurologic.

Effectiveness

Lack of efficacy - NOS (1) • Dog Lack of efficacy (endoparasite) - hookworm (1) • Dog Lack of efficacy (1) • Cat

Showing top 5 for Effectiveness.

Other

Oliguria (1) • Dog Not himself/herself (1) • Cat Not defecating (1) • Dog Low thyroxine (1) • Cat Leucocytosis NOS (1) • Cat

Show more (19)

High thyroid stimulating hormone (1) • Cat General illness (1) • Dog Excoriation (1) • Dog Erythema (1) • Dog Elevated thyroxine (1) • Cat Elevated liver enzymes NOS (1) • Dog Elevated blood urea nitrogen (1) • Cat Elevated amylase (1) • Cat Dilated pupils (1) • Cat Decreased urine concentration (1) • Dog Decreased drinking (1) • Dog Cough (1) • Dog Circumstance or info capable of leading to medication error (1) • Cat Bacterial skin infection NOS (1) • Dog Aspiration pneumonia (1) • Dog Allergic reaction (1) • Cat Agitation (1) • Cat Accidental exposure (1) • Cat Abnormal cytology (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, Female, 13 year, 6.12 kilogram • Drug: MSK, Unassigned, Unknown, Dose: 0.50 tablet per animal, Frequency: 24 per hour • Reactions: Partial lack of efficacy, Hair loss, Erythema, Papule, Excoriation… • Outcome: Ongoing

Report ID: USA-USFDACVM-2025-US-055162
Serious AE: Yes
Treated For AE: Yes
Sex: Female
Age: 13.00 Year
Weight: 6.120 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Unknown
Form: Unassigned
Dose: 0.50 tablet per animal
Frequency: 24 per hour

Reactions Reported:

Partial lack of efficacy Hair loss Erythema Papule Excoriation Skin scab Bacterial skin infection NOS Abnormal cytology

Outcomes: Ongoing

Dog, Spitz - German Pomeranian, Male, 4 year, 4.205 kilogram • Drug: MSK, Unassigned, Unknown • Reactions: Shaking, Tiredness (lethargy), Tense abdomen, Swallowing disorder NOS, Diarrhea • Outcome: Recovered/Normal

Report ID: USA-USFDACVM-2025-US-053196
Serious AE: Yes
Treated For AE: Yes
Sex: Male
Age: 4.00 Year
Weight: 4.205 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Unknown
Form: Unassigned

Reactions Reported:

Shaking Tiredness (lethargy) Tense abdomen Swallowing disorder NOS Diarrhea

Outcomes: Recovered/Normal

Dog, ['Boxer (German Boxer)', 'Dog (unknown)'], Male, 10 year, 35.153 kilogram • Drug: MSK, Unassigned, Unknown • Reactions: General illness, Aspiration pneumonia, Cough, Not defecating • Outcome: Ongoing

Report ID: USA-USFDACVM-2025-US-053209
Serious AE: No
Treated For AE: Yes
Sex: Male
Age: 10.00 Year
Weight: 35.153 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Unknown
Form: Unassigned

Reactions Reported:

General illness Aspiration pneumonia Cough Not defecating

Outcomes: Ongoing

Dog, Crossbred Canine/dog, Female, 13 year, 24.5 kilogram • Drug: MSK, Oral • Reactions: Decreased appetite, Decreased drinking, Weakness, Lack of efficacy - NOS, Weight gain… • Outcome: Outcome Unknown

Report ID: USA-USFDACVM-2025-US-047132
Serious AE: No
Treated For AE: Yes
Sex: Female
Age: 13.00 Year
Weight: 24.500 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Oral

Reactions Reported:

Decreased appetite Decreased drinking Weakness Lack of efficacy - NOS Weight gain Elevated liver enzymes NOS Oliguria Urinary tract infection Decreased urine concentration

Outcomes: Outcome Unknown

Dog, ['Retriever - Labrador', 'Poodle (unspecified)'], Male, 10 year, 49.44 kilogram • Drug: MSK, Oral, Dose: 0.80 Milligram per animal • Reactions: Lack of efficacy (endoparasite) - hookworm • Outcome: Outcome Unknown

Report ID: USA-USFDACVM-2025-US-043985
Serious AE: No
Treated For AE: Yes
Sex: Male
Age: 10.00 Year
Weight: 49.440 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Oral
Dose: 0.80 Milligram per animal

Reactions Reported:

Lack of efficacy (endoparasite) - hookworm

Outcomes: Outcome Unknown

Cat, Domestic Shorthair, Male, 13 year, 5.12 kilogram • Drug: MSK, Pill, Oral, Dose: 0.10 Milligram per animal, Frequency: 1 per day • Reactions: Drooling, Not himself/herself, Dilated pupils, Agitation • Outcome: Ongoing

Report ID: USA-USFDACVM-2023-US-045191
Serious AE: No
Treated For AE: No
Sex: Male
Age: 13.00 Year
Weight: 5.120 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Oral
Form: Pill
Dose: 0.10 Milligram per animal
Frequency: 1 per day

Reactions Reported:

Drooling Not himself/herself Dilated pupils Agitation

Outcomes: Ongoing

Cat, Female, 11 year, 4.7 kilogram • Drug: MSK, Tablet, Oral, Dose: 0.6870 Milligram per kilogram, Frequency: 1 per day • Reactions: Overdose, Accidental exposure, Elevated blood urea nitrogen, Elevated amylase, Leucocytosis NOS • Outcome: Recovered/Normal

Report ID: USA-USFDACVM-2021-US-016634
Serious AE: Yes
Treated For AE: Yes
Sex: Female
Age: 11.00 Year
Weight: 4.700 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Oral
Form: Tablet
Dose: 0.6870 Milligram per kilogram
Frequency: 1 per day

Reactions Reported:

Overdose Accidental exposure Elevated blood urea nitrogen Elevated amylase Leucocytosis NOS

Outcomes: Recovered/Normal

Cat, Maine Coon, Male, 6.5 year, 8.6 kilogram • Drug: MSK, Tablet, Oral, Dose: 0.0923 Milligram per kilogram, Frequency: 24 per hour • Reactions: Accidental exposure, Circumstance or info capable of leading to medication error • Outcome: Outcome Unknown

Report ID: USA-USFDACVM-2018-US-029183
Serious AE: No
Treated For AE: No
Sex: Male
Age: 6.50 Year
Weight: 8.600 Kilogram

Case-reported brand: MSK
Case-reported manufacturer: MSK
Route: Oral
Form: Tablet
Dose: 0.0923 Milligram per kilogram
Frequency: 24 per hour

Reactions Reported:

Accidental exposure Circumstance or info capable of leading to medication error

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.

Share Your Thoughts

Let others know your experience or advice regarding this medication.

No community reviews yet. Be the first to share your experience.

This medication has not been reviewed by a veterinarian yet.

Medical Disclaimer: The medication details provided on Roxee are for informational purposes only and are not a substitute for professional veterinary advice. Always consult your veterinarian about your pet's specific needs.

Levothyroxine Sodium

Add to My Pet's Meds

Reviewed / Updated / Sources

Pet Owner Quick Guide