VETERINARY TEAM REFERENCE

DEA & state schedules

Scheduling applies to the medication, not to the patient. This independent reference is not affiliated with the DEA.

Methimazole

FEDERAL STATUS

Not federally scheduled

The identified ingredients in this entry are not listed in the reviewed federal schedules. Prescription-only status, product restrictions and state law are separate questions.

Federal source ↗

State / prescribing or dispensing jurisdiction

STATE STATUS

Select a jurisdiction

Choose the state relevant to prescribing or dispensing. Patient residence alone may not determine every applicable rule.

What each federal schedule means

Highlighted rows match the verified federal or selected state schedule. The schedule describes legal control and abuse potential; it does not rank clinical usefulness or establish a dose.

Federal Schedules I–V: meaning and practice implications
Schedule	Meaning and practice
I	High abuse potential; no currently accepted medical use in U.S. treatment; lacks accepted safety under medical supervision. In practice: Not available for routine veterinary prescribing. Authorized research is a separate pathway.
II	High abuse potential; accepted medical use, sometimes with severe restrictions; abuse can cause severe dependence. In practice: No prescription refills under federal law. Strict prescribing, security and record requirements apply.
III	Less abuse potential than I or II; accepted medical use; abuse can cause moderate or low physical dependence or high psychological dependence. In practice: Federal prescriptions allow up to five authorized refills within six months. State rules may be stricter.
IV	Lower abuse potential than III; accepted medical use; limited dependence risk relative to III. In practice: The same federal five-refill / six-month prescription limit applies. Controlled-drug handling still applies.
V	Lower abuse potential than IV; accepted medical use; limited dependence risk relative to IV. In practice: Still controlled. Check authorized refills and state limits; do not automatically apply the III–IV refill rule.

What this means for the chart

For a controlled medication, confirm the prescriber’s authority for the applicable schedule, the exact formulation and quantity, authorized refills, secure handling, and required inventory / dispensing records. Check the state’s veterinary rules and any prescription monitoring program (PDMP) requirements or exemptions.

A PDMP reporting requirement does not by itself make a drug scheduled. “Not federally scheduled” does not mean over the counter, risk-free, or exempt from state law. States may use additional categories, such as Schedule VI, outside the federal I–V system.

← Medication & Supplement Reference

VETERINARY TEAM REFERENCE · MEDICATION

Methimazole

An antithyroid medication that reduces thyroid hormone synthesis. Felimazole coated tablets are labeled for feline hyperthyroidism; successful treatment needs biochemical and clinical monitoring.

Thyroid synthesis inhibitorProduct-specific clinical reference

Updated October 16, 2026 · Sources and review status below

For veterinarians and veterinary staff. Product-label information is distinct from extra-label clinical practice. This is not a complete prescribing formulary or an automated interaction screen. Verify the current label, exact formulation, patient and species-specific clinical reference before use. Independent veterinary/pharmacy review remains pending.

Prescribing overview

Felimazole coated tablets treat feline hyperthyroidism.

Key prescribing checks

The feline label lists contraindications including primary liver disease, renal failure, autoimmune disease, specified blood disorders and pregnancy or lactation. Read the full list before treatment.
Monitor blood counts, biochemistry and total T4 according to the clinical plan. Treating hyperthyroidism can uncover underlying renal dysfunction.
Facial itching, vomiting, anorexia, lethargy or other illness during treatment needs prompt assessment; potentially serious hepatic or blood-cell reactions are described.
Follow handling precautions for tablets and body wastes, especially for pregnant or breastfeeding handlers. Wash hands after administration.

Uses by species

Approval and evidence apply to the named product, species, route and indication. An extra-label use requires its own prescribing assessment; a human indication is not an animal approval.

Cats

FDA-approved veterinary label

Hyperthyroidism

Contraindicated with specified liver, renal, autoimmune or blood disease and pregnancy/lactation.

Use / indication source ↗

Pharmacology & pharmacokinetics

Mechanism and clinical role

Inhibits thyroid-peroxidase-dependent hormone synthesis.

Absorption, distribution, metabolism and elimination

Cats: peak plasma concentrations at 1–1.5 hours; blood half-life approximately 3 hours.

SAFETY REFERENCE · PRODUCT & SPECIES SPECIFIC

Contraindications & cautions

Contraindications identify circumstances where the source says a product should not be used. Precautions call for assessment or monitoring. Interactions identify combinations to review. They are distinct categories; this summary does not replace a full interaction check or the current product label.

Felimazole

Cats; coated oral tablets

Contraindications · when not to use

Hypersensitivity to methimazole, carbimazole or polyethylene glycol.
Primary liver disease, renal failure or autoimmune disease.
Blood-cell disorders or coagulopathies.
Pregnancy or lactation.

Precautions & monitoring

Monitor blood counts, liver and renal function; serious illness requires prompt assessment.

Safety sources checked: October 16, 2026. Selected label information; independent veterinary or veterinary-pharmacy review remains pending. A label for dogs, cats, horses or humans does not establish safety for another species.

Adverse effects

Vomiting, facial itching, hepatopathy and serious blood-cell disorders can occur; treatment may unmask renal disease.

These are selected source-reported effects, not incidence estimates or an exhaustive list. Spontaneous postmarketing reports do not by themselves establish frequency or causality.

Dosing & administration

Verify the source before prescribing. The regimens below summarize selected veterinary product labels, not every accepted veterinary use. They are not automatic substitutions between brands or formulations. Renal/hepatic disease, concurrent therapy, age, indication and clinical response can require a different plan.

Selected product-label regimens — not a patient-specific prescription
Species & indication	Labeled regimen	Eligibility & source
CatsHyperthyroidismFelimazole coated tablets	Initially 2.5 mg/cat Oral · Every 12 hours Ongoing; veterinarian-titrated	Maximum 20 mg/day divided; maximum 10 mg per administration. Verify full dosing label ↗

Adjust in 2.5 mg increments after 3 weeks using TT4 and clinical response.

Extra-label prescribing and food-animal residue requirements are separate from labeled regimens. FDA extra-label-use guidance ↗

Drug & supplement interactions

This is a selected interaction reference, not an automated or comprehensive combination checker. Reconcile prescription drugs, nonprescription products, supplements and recent treatment changes.

Felimazole

Cats; coated oral tablets

Anticoagulant effects may increase; phenobarbital may reduce efficacy and benzimidazole exposure may rise.

Interaction source ↗

Monitoring

CBC, chemistry and TT4 before treatment, at 3 and 6 weeks, then every 3 months; more often above 10 mg/day.

Client counseling

If illness develops, stop treatment and contact the veterinarian. Do not crush/break tablets; use gloves for body wastes.

This section supports the veterinary team's discharge discussion; it does not replace the product’s Client Information Sheet where one is required.

Storage & handling

Follow labeled storage; wash hands after administration.

Brands, formulations & ingredient identity

Active ingredients

methimazole

Felimazole identifies methimazole. It is not levothyroxine, which is thyroid hormone replacement and serves a different purpose.

The labeled coated tablets should not be broken or crushed. A compounded liquid or transdermal preparation is a separate formulation, not the branded tablet in another package.

Carbimazole is related pharmacologically but is not an ingredient synonym to substitute without prescriber review.

Shared ingredients do not establish interchangeable concentrations, routes, release properties, species labeling or regional availability.

Felimazole

Formulation: Coated oral tablets
Label / product scope: Cats

Feline prescription antithyroid product; tablets must not be crushed or broken.

Product label / source ↗

References & review status

Clinical reference updated October 16, 2026. Independent veterinary or veterinary-pharmacy review not yet completed. Evidence gaps remain explicitly identified; this page does not claim equivalence to a comprehensive, professionally reviewed veterinary formulary.

01DailyMed: methimazole product labeling ↗

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Prescribing overview

Key prescribing checks

Uses by species

Cats

Pharmacology & pharmacokinetics

Mechanism and clinical role

Absorption, distribution, metabolism and elimination

Contraindications & cautions

Contraindications · when not to use

Precautions & monitoring

Adverse effects

Dosing & administration

Drug & supplement interactions

Felimazole

Monitoring

Client counseling

Storage & handling

Brands, formulations & ingredient identity

Active ingredients

Felimazole

References & review status

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