Roxee Medication Guide

Methimazole

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

Cat Reference complete FDA data linked Rx required Coated Tablets Multiple FDA labelers 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

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 Aug 4, 2026, 10:01 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

Methimazole

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

Cat Coated Tablets Rx required 100% reference complete

Species: Cat

Manufacturer: Multiple FDA labelers

Medication Snapshot

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

Methimazole

Used to manage hyperthyroidism in cats. Species commonly shown: Cat.

Generic name

Methimazole

Brand names

Felimazole®, Felanorm®, Methimazole Coated Tablets, Methimazole Oral Solution

Manufacturer

Multiple FDA labelers

Species

Cat

Dosage forms

Coated Tablets, Oral Solution

Prescription

Prescription required

Completeness

100%

Validation

Complete

Brand names

Felimazole® Felanorm® Methimazole Coated Tablets Methimazole Oral Solution Methimazole Felanorm Felimazole ReguZol

Dosage forms

Coated Tablets Oral Solution

Indications / Uses

Used to manage hyperthyroidism in cats.

Administration / How To Give

Oral

Storage

Store at room temperature.

Warnings / Contraindications

Use caution with liver disease, blood disorders, or autoimmune conditions.

Use caution with liver disease, blood disorders, or autoimmune conditions.

Side Effects

Vomiting, decreased appetite, lethargy, facial itching. Rare: low blood cell counts.

FAQ

Cat

Yes. Roxee shows this as prescription-only.

Coated Tablets, Oral Solution

Store at room temperature.

Related Medications

Related Conditions

Anemia (regenerative/non-regenerative) Hyperthyroidism Hyperthyroidism Pruritus (itching, undifferentiated) Thrombocytopenia (ITP) Weight loss

Source Transparency

Verified source: https://www.roxee.ai/meds/
Verified source: https://animaldrugsatfda.fda.gov
Verified source: https://animaldrugsatfda.fda.gov/adafda/views/#/search
Verified source: https://api.fda.gov/animalandveterinary/event.json
Verified source: https://www.roxee.ai/conditions/
Verified source: /static/meds/images/methimazole.jpg
Last refreshed: Aug 6, 2026, 7:47 p.m.
Last verified: Feb 12, 2026, 7:40 p.m.
Validation status: Complete

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Pet Owner Quick Guide

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

Used for:

Methimazole Oral Solution is indicated for the treatment of hyperthyroidism in cats.

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:

Use caution with liver disease, blood disorders, or autoimmune conditions
wobbly/unsteady walking (1 reports)
Loss of appetite (1 reports)
Elevated blood urea nitrogen (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 Methimazole; use the official documents and your veterinarian's instructions for product-specific decisions.

Source: openFDA case USA-USFDACVM-2025-US-069686

Safety signal coverage Reported signals

32 tracked reaction signals; 32 reported cases; 29 serious reports; 2 species groups. These are reporting and label-derived signals for interpretation with a veterinarian.

Source: openFDA case USA-USFDACVM-2025-US-069686

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-2025-US-069686

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

Unsteady walking (ataxia) (1 reports), Loss of appetite (1 reports), Elevated blood urea nitrogen (1 reports), Elevated amylase (1 reports), Elevated alanine aminotransferase (1 reports)

Body systems represented Signal grouping

Digestive (2), Neurologic (1), Behavior (2), Other (27)

Explore supporting adverse reports

Species and breed lens

Species represented in reports Species lens

Cat (31 reports), Dog (1 reports)

Breed metadata in reports Metadata only

Domestic Shorthair (5), Domestic Mediumhair (2), Shepherd Dog - Australian (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 Methimazole 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

Use caution with liver disease, blood disorders, or autoimmune conditions, wobbly/unsteady walking, Loss of appetite, Elevated blood urea nitrogen

Call sooner if Escalation

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

Bottom line: Use this Methimazole 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

openFDA case USA-USFDACVM-2025-US-069686 · adverse_reaction · adverse reactions
Contraindication source · fda_animal_drugs · warnings contraindications
FDA application profile · official_label · quick facts
FDA application profile · official_label · quick facts
Medication usage source · fda_animal_drugs · quick facts
FOI · document · documents
SPL · document · documents
FOI · document · documents

Evidence

Review status / Updated / Sources

Review status: Clinical reviewer not listed

Updated: February 12, 2026, 7:40 PM UTC

Sources:

FDA application profile · official_label
FDA application profile · official_label
Medication usage source · fda_animal_drugs
Felanorm® · official_label
openFDA case USA-USFDACVM-2025-US-069686 · adverse_reaction

Safety & side effects

Side effects to monitor:

Use caution with liver disease, blood disorders, or autoimmune conditions
wobbly/unsteady walking
Loss of appetite
Elevated blood urea nitrogen

Most reported reactions:

Unsteady walking (ataxia) (1 reports)
Loss of appetite (1 reports)
Elevated blood urea nitrogen (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

Cat

Indication / use

Methimazole Oral Solution is indicated for the treatment of hyperthyroidism in cats.

Form / route / dose

Form: Coated Tablets, Oral Solution
Route: Oral
Confirm product label and patient-specific plan.

Warnings

High: Use caution with liver disease, blood disorders, or autoimmune conditions.

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: Cat

Manufacturer: Multiple FDA labelers

Form: Coated Tablets, Oral Solution

Identifiers:

ANADA: 200771 ANADA: 200814 ANADA: 200860 NADA: 141292 NDC Package: 11695-7048-1 NDC Package: 11695-7049-1 NDC Package: 17033-225-10 NDC Package: 17033-250-10 NDC Package: 51311-044-30 NDC Package: 51311-044-40 NDC Package: 55529-170-02 NDC Package: 55529-170-14 NDC Package: 86032-064-01 NDC Package: 86101-059-11 NDC Package: 86101-060-11 NDC Package: 86136-157-36 NDC Package: 86136-158-36 NDC Product: 11695 NDC Product: 17033 NDC Product: 51311

Source metadata:

https://animaldrugsatfda.fda.gov/adafda/views/#/home/previewsearch/200860 · official_label · FDA application profile
https://animaldrugsatfda.fda.gov/adafda/views/#/home/previewsearch/141292 · official_label · FDA application profile
https://animaldrugsatfda.fda.gov · fda_animal_drugs · Medication usage source

Warnings / Contraindications

Use caution with liver disease, blood disorders, or autoimmune conditions.

High: Use caution with liver disease, blood disorders, or autoimmune conditions.

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.

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

Matching reports

Active filters

Selected filters

Reaction: Behavioural disorder NOS Clear

Species

Breed

Size / weight

Age

Sex

Seriousness

Outcome

Reaction

Body system

Region

Received after

Received before

Reset

Drill into common report signals

Behavioural disorder NOS (4) Medication error NOS (4) Vomiting (4) Tachycardia (3) Other (19) Digestive (8) Behavior (5) Neurologic (3)

Showing up to 50 matching reports.

USA-USFDACVM-2026-US-001377

Received 2026-01-12 · MSK · MSK

Serious

Species: Cat
Breed: Domestic Longhair
Size / weight: Under 10 lb (4.064 Kilogram)
Age: 8+ years (15 Year)
Sex: Female Unknown
Region: USA
Reactions: DermatitisSkin ulcerLack of efficacy - NOSAbnormal histology NOSBehavioural disorder NOSVocalisationTachycardiaHigh blood pressureRetinal disorder NOSGranulomaDecreased appetitePain NOSWeight lossAbnormal menace reflex testDilated pupilsLoss of visionSkin irritationInjection site dermatitisElevated blood urea nitrogen (BUN)PacingElevated amylaseHypokalaemiaElevated symmetrical dimethylarginine (SDMA)Vomiting bile
Body systems: OtherEffectivenessBehaviorDigestive
Outcomes: Ongoing

USA-USFDACVM-2025-US-074332

Received 2025-12-17 · MSK · MSK

Serious

Species: Cat
Breed: Domestic Shorthair
Size / weight: 10-24 lb (6.876 Kilogram)
Age: 8+ years (13 Year)
Sex: Male Neutered
Region: USA
Reactions: FeverNot eatingNeutrophiliaMonocytosisImmune mediated haemolytic anaemiaBehavioural disorder NOSDecreased haematocrit
Body systems: OtherBehavior
Outcomes: Ongoing

USA-USFDACVM-2025-US-072860

Received 2025-12-12 · MSK · MSK

Serious

Species: Cat
Breed: Domestic Shorthair
Size / weight: Under 10 lb (4.128 Kilogram)
Age: 8+ years (16 Year)
Sex: Female Unknown
Region: USA
Reactions: Seizure NOSWobblinessInappropriate elimination NOSVocalisationDistressBehavioural disorder NOSHead twitchingEye disorder NOS (for Photophobia see neurological)ConfusionAbnormal movement NOS
Body systems: NeurologicOtherBehaviorSkin & allergy
Outcomes: Ongoing

USA-USFDACVM-2025-US-074045

Received 2025-12-11 · MSK · MSK

Non-serious

Species: Cat
Breed: Domestic Shorthair
Size / weight: 10-24 lb (5.4 Kilogram)
Age: 8+ years (15 Year)
Sex: Female Neutered
Region: USA
Reactions: VomitingBehavioural disorder NOSUNPALATABLE
Body systems: DigestiveBehaviorOther
Outcomes: Outcome Unknown

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 (2) · Loss of appetite, Decreased appetite Neurologic (1) · Unsteady walking (ataxia) Behavior (2) · Behavioral disorder (unspecified), Anxiety Other (27) · Elevated blood urea nitrogen, Elevated amylase, Elevated alanine aminotransferase

Most Reported Reactions

Body system	Cases	Species	Serious cases
Neurologic	1	Cat	1
Digestive	1	Cat	1
Other	1	Cat	1
Other	1	Cat	1
Other	1	Cat	1
Other	1	Cat	1
Other	1	Cat	1
Other	1	Cat	1

Species coverage: Cat (31) Dog (1)

View detailed reaction table

Body system	Species	Seriousness	Frequency	Reports
Neurologic	Cat	Serious	-	1
Digestive	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Non-serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Non-serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Digestive	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Behavior	Cat	Serious	-	1
Other	Cat	Serious	-	1
Behavior	Dog	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Non-serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1
Other	Cat	Serious	-	1

Source metadata:

https://api.fda.gov/animalandveterinary/event.json · adverse_reaction · openFDA case USA-USFDACVM-2025-US-069686

Storage & Handling

Store at room temperature.

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.

Methimazole Oral Solution SPL · SPL Felimazole® SPL · SPL Felanorm® SPL · SPL

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

Owner handouts

No owner handouts linked yet.

Official label / PI

No official label or package insert links yet.

SPL

FOI

Methimazole Oral Solution

SPL · SPL

Open original

FDA Structured Product Label

Methimazole Oral Solution

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

Sponsor: Felix Pharmaceuticals Pvt. Ltd.
ANADA: 200-860
Status: RX
Form: Oral Solution
Route: Oral

Composition / specifications

5 mg/mL

Cats

Indication

Methimazole Oral Solution is indicated for the treatment of hyperthyroidism in cats.

Dosage

Administer a starting dose of 2.5 mg every 12 hours. Following 3 weeks of treatment, the dose should be titrated to effect based on individual serum total T4 (TT4) levels and clinical response. Dose adjustments should be made in 2.5 mg increments with a maximum dosage of 20 mg per day divided, not to exceed 10 mg as a single dose.

Felimazole®

SPL · SPL

Open original

FDA Structured Product Label

Felimazole®

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

Sponsor: Dechra Veterinary Products LLC
NADA: 141-292
Status: RX
Form: Coated Tablets
Route: Oral
Species: Cat

Cats

Indication

For the treatment of hyperthyroidism in cats.

Dosage

The starting dose is 2.5 mg administered every 12 hours. Following three weeks of treatment, the dose should be titrated to effect based on individual serum total T4 (TT4) levels and clinical response. Dose adjustments should be made in 2.5 mg increments. The maximum total dosage is 20 mg per day divided, not to exceed 10 mg as a single administration.

Limitations

Due to potentially serious adverse reactions such as hepatopathy, immune-mediated anemia, thrombocytopenia, and agranulocytosis, cats on methimazole therapy should be monitored closely for any sign of illness including anorexia, vomiting, head/facial pruritus or edema, depression/lethargy, weight loss, anemia, skin lesions, diarrhea, fever, or lymphadenopathy. If a cat becomes ill while on FELIMAZOLE Coated Tablets, the drug should be stopped and appropriate hematological and biochemical testing should be done (see ANIMAL SAFETY and POST APPROVAL EXPERIENCE).

Felanorm®

SPL · SPL

Open original

FDA Structured Product Label

Felanorm®

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

Sponsor: Virbac AH, Inc.
ANADA: 200-771
Status: RX
Form: Oral Solution
Route: Oral

Composition / specifications

5 mg/mL

Cats

Indication

For the treatment of hyperthyroidism in cats.

Dosage

The starting dose is 2.5 mg administered every 12 hours. Following 3 weeks of treatment, the dose should be titrated to effect based on individual serum total T4 (TT4) levels and clinical response. Dose adjustments should be made in 2.5 mg increments. The maximum total dosage is 20 mg per day divided, not to exceed 10 mg as a single administration.

Methimazole Coated Tablets

SPL · SPL

Open original

FDA Structured Product Label

Methimazole Coated Tablets

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

Sponsor: Felix Pharmaceuticals Pvt. Ltd.
ANADA: 200-814
Status: RX
Form: Coated Tablets
Route: Oral

Composition / specifications

2.5 mg or 5 mg methimazole per tablet

Cats

Indication

For the treatment of hyperthyroidism in cats.

Dosage

The starting dose of Methimazole Coated Tablets is 2.5 mg administered every 12 hours. Following 3 weeks of treatment, the dose should be titrated to effect based on individual serum total T4 (TT4) levels and clinical response. Dose adjustments should be made in 2.5 mg increments. The maximum total dosage is 20 mg per day divided, not to exceed 10 mg as a single administration.