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Active substance

Methimazole

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Thioimidazole antithyroid. No registration in force in Georgia. Forms: coated tablet, solution.

Dose and use

Doses

Each dose comes with its source. Check the label of the product you use.

Active substance Methimazole
Dose Species Indication Route Frequency Source
5 mg per animal
at most 20 mg
 Cat Hyperthyroidism By mouth total daily dose divided between morning and evening
Felimazole 2.5 mg comparator SPC
Official product label (SPC)
Approved by a medicines regulator as part of the product's authorisation. It applies to that product as authorised there.
Felimazole 2.5 mg Coated Tablets for Cats - Summary of Product Characteristics
UK Veterinary Medicines Directorate, 2026
2.5 mg per animal
at most 10 mg
 Cat Hyperthyroidism By mouth 2 times daily
FDA Felimazole approval record
Official product label (SPC)
Approved by a medicines regulator as part of the product's authorisation. It applies to that product as authorised there.
Felimazole (methimazole) Coated Tablets - dosage (SPL view) and Freedom of Information Summary
FDA (NADA 141-292), 2026
1.25–2.5 mg per animal
off-label
 Cat Hyperthyroidism By mouth 2 times daily
AAFP feline hyperthyroidism guideline
Guideline or consensus statement
Recommendations agreed by a panel of veterinary specialists after reviewing the evidence. They guide practice and do not authorise a product.
2016 AAFP Guidelines for the Management of Feline Hyperthyroidism
Journal of Feline Medicine and Surgery, 2016
Before use

Safety information

Known Contraindications

  • Critical
    Do not use in cats with primary liver disease or renal failure. should be subject to careful benefit-risk assessment by the clinician
    Sources: FDA
  • Critical
    Do not use thiamazole in cats with primary liver disease.
    Sources: FDA
  • Critical
    Some product labels contraindicate thiamazole in cats with diabetes mellitus. Follow the selected product’s label and monitor glycaemic control closely if treatment is considered.
    Sources: Product label
  • Critical
    Do not use thiamazole in animals with platelet disorders or coagulopathies, especially thrombocytopenia. Thiamazole can impair vitamin K activity and may cause a bleeding tendency even without thrombocytopenia.
    Sources: FDA
  • Critical
    Do not use in cats with hematological disorders (such as anemia, neutropenia, lymphopenia, or thrombocytopenia) or coagulopathies.
    Sources: FDA
  • Critical
    Do not use thiamazole during pregnancy. Teratogenic and embryotoxic effects have been demonstrated in laboratory animals.
    Sources: FDA
  • Critical
    Do not use thiamazole during lactation because substantial transfer into milk may occur.
  • Critical
    Known hypersensitivity to thiamazole (methimazole), carbimazole, or any excipient is a contraindication.
  • Caution
    Monitor haematology, serum biochemistry, and T4 before methimazole treatment, then at 3, 6, 10, and 20 weeks and every 3 months because leucopenia or haemolytic anaemia may occur.
    Sources: Felimazole SPC

Known Drug Interactions

  • Major warning Methimazole + Enoxaparin
    Anticoagulants may be potentiated anti-vitamin K activity
    Recommendation: Monitor for signs of bleeding.
    Sources: FDA
  • Minor warning Phenobarbital + Methimazole
    Phenobarbital can reduce the clinical efficacy of thiamazole when the drugs are used together.
    Recommendation: Recheck T4 and clinical response.
  • Minor warning Fenbendazole + Methimazole
    Thiamazole reduces hepatic oxidation of benzimidazole anthelmintics and can increase their plasma concentrations during concurrent treatment.
    Recommendation: Higher fenbendazole concentrations are expected during concomitant administration.
  • Minor warning Atenolol + Methimazole
    A reduction in dose of certain drugs (β-adrenergic blocking agents, digitalis glycosides, and theophylline) may be needed when the patient becomes euthyroid.
    Recommendation: Reassess the dose once euthyroidism is achieved.
    Sources: FDA
  • Minor warning Theophylline + Methimazole
    A reduction in dose of certain drugs (β-adrenergic blocking agents, digitalis glycosides, and theophylline) may be needed when the patient becomes euthyroid.
    Recommendation: Reassess the dose once euthyroidism is achieved.
    Sources: FDA
Latin name
Methimazole
Georgian name
თიამაზოლი (მეთიმაზოლი)
Authorisation status
Authorised veterinary medicine
An authorised veterinary medicine containing this substance exists. Whether a particular use is on-label depends on the species and the indication - see each dose rule.
Registered in Georgia
0 of 2 forms
Controlled in Georgia
No
Checked against the narcotics law, Annex 1, lists I-IV, and Order No. 22/n.
Verified on: 16 Oct 2026
All forms and registration2

Registration in Georgia and abroad: the register, number, validity and source are behind (i).

Thiamazole 2.5 mg, Coated tablet

coated tablet for cats
vetman assessment
vetman’s 10-point assessment brings together a product’s regulatory credibility, clinical efficacy, safety and practicality. Cost-effectiveness is assessed only when reliable data are available. It is informational and does not replace a veterinarian’s clinical judgment for an individual patient.
Cat
Not rateable
No numerical score assigned
vetman assessment

Thiamazole 2.5 mg

coated tablet for cats
Assessed clinical scopeCat · Potential oral stabilisation before thyroidectomy or long-term medical control of feline hyperthyroidism with this unidentified 2.5 mg coated tablet · By mouth
Care settingVeterinary treatment only after confirmed feline hyperthyroidism and exact-product identification, with individual titration and serial clinical, TT4, CBC, chemistry, blood-pressure and renal assessment.
vetman score Not rateable No numerical score assigned
Evidence confidence: Low Georgia: Unknown · Verified on 22 Oct 2026
Not rateable

A numerical product score cannot responsibly be assigned. Catalogue row 20926 states thiamazole, strength, oral form and cat target species but has no trade name, manufacturer/MA holder, authorisation number, pack or exact current label. Existing market statuses and dose/handling text were transferred from named products. Felimazole, Thyronorm and approved generics support thiamazole clinical use, but cannot establish this unidentified presentation authorisation, pharmaceutical equivalence, quality, excipients, dose delivery, storage, in-use limits or product-specific safety.

Named authorised thiamazole tablets are established feline hyperthyroidism options, but their positive product score, tablet integrity and regimen cannot be transferred to an unidentified 2.5 mg tablet. Map this row to the exact pack before scoring or dosing.

Important safety and use flags

  • Exact product identity is missing. Do not infer trade name, manufacturer/MA holder, authorisation, pack, excipients, dispenser, storage or quality from the generic catalogue description.
  • Felimazole, Thyronorm and other named approved products are comparators, not the products identified by these rows. Their authorisations, formulation-specific evidence and handling instructions must not be transferred.
  • No calculator dose is published for this unidentified presentation. Confirm the actual product and current label before prescribing; equal ingredient, strength and form do not prove pharmaceutical or dose-delivery equivalence.
  • Thiamazole controls thyroid-hormone production but is not curative. Discuss definitive treatment options and reassess the long-term plan for the individual cat.
  • Obtain baseline and serial clinical status, body weight, TT4, CBC, chemistry, blood pressure and renal assessment; titrate to the lowest effective exact-label regimen and investigate adverse changes promptly.
  • Restoring euthyroidism can unmask or worsen renal dysfunction. Evaluate renal status and perfusion before and during titration rather than withholding all treatment automatically.
  • Primary hepatic disease, important haematologic/coagulation or autoimmune disorders, diabetes, pregnancy/lactation and hypersensitivity carry major restrictions in named labels; the exact current product label and patient status must be checked.
  • Review phenobarbital, benzimidazole anthelmintics, anticoagulants and medicines whose required dose can change after euthyroidism. Do not assume the interaction section is identical across unidentified products.
  • Thiamazole is a human reproductive/occupational hazard. Use gloves and follow the exact leaflet for tablets, solution, spills, vomit and used litter; pregnant or potentially pregnant handlers require particular protection.
  • Do not transfer Felimazole claims that a tablet must not be split, broken or crushed, or its pack/storage limits, until this 2.5 mg tablet is exactly identified.
Assessment sources
  1. Thiamazole product identity audit2026
  2. Felimazole 2.5 mg comparator SPC2026
  3. Thyronorm 5 mg/ml comparator SPC2026
  4. FDA Felimazole approval record2026
  5. FDA approved generic bioequivalence2025
  6. AAFP feline hyperthyroidism guideline2016
  7. Current VMD thiamazole product list2026
Assessed: 22 Oct 2026No axis or overall score is shown when the available evidence does not support a responsible numerical assessment.
Composition / strength
Methimazole2.5 mg
Formulation Type
Coated tablet
Administration route
By mouth
Manufacturer
-
Product
generic presentation, not registered in Georgia under a trade name
Registration
Georgia Unknown EU Not confirmed
Verified on: 22 Oct 2026
 UK Not confirmed
Verified on: 22 Oct 2026
 US Not confirmed
Verified on: 22 Oct 2026
Controlled in Georgia
No
Checked against the narcotics law, Annex 1, lists I-IV, and Order No. 22/n.
Verified on: 16 Oct 2026
Information not fully verified No exact-product dose is published. Felimazole and other named 2.5 mg thiamazole tablets are authorised comparators, not the product identified by this row. Confirm the trade name, manufacturer/MA holder, authorisation, pack and current label before using a product-specific dose, splitting/crushing rule, storage limit or monitoring instruction.

Thiamazole 5 mg/ml, Solution

oral solution for cats
vetman assessment
vetman’s 10-point assessment brings together a product’s regulatory credibility, clinical efficacy, safety and practicality. Cost-effectiveness is assessed only when reliable data are available. It is informational and does not replace a veterinarian’s clinical judgment for an individual patient.
Cat
Not rateable
No numerical score assigned
vetman assessment

Thiamazole 5 mg/ml

oral solution for cats
Assessed clinical scopeCat · Potential oral stabilisation before thyroidectomy or long-term medical control of feline hyperthyroidism with this unidentified 5 mg/ml oral solution · By mouth
Care settingVeterinary treatment only after confirmed feline hyperthyroidism and exact-product identification, with individual titration and serial clinical, TT4, CBC, chemistry, blood-pressure and renal assessment.
vetman score Not rateable No numerical score assigned
Evidence confidence: Low Georgia: Unknown · Verified on 22 Oct 2026
Not rateable

A numerical product score cannot responsibly be assigned. Catalogue row 20927 states thiamazole, strength, oral form and cat target species but has no trade name, manufacturer/MA holder, authorisation number, pack or exact current label. Existing market statuses and dose/handling text were transferred from named products. Felimazole, Thyronorm and approved generics support thiamazole clinical use, but cannot establish this unidentified presentation authorisation, pharmaceutical equivalence, quality, excipients, dose delivery, storage, in-use limits or product-specific safety.

Named authorised thiamazole solutions are established feline hyperthyroidism options, but their positive product score, dispenser accuracy, handling and regimen cannot be transferred to an unidentified 5 mg/ml solution. Map this row to the exact pack before scoring or dosing.

Important safety and use flags

  • Exact product identity is missing. Do not infer trade name, manufacturer/MA holder, authorisation, pack, excipients, dispenser, storage or quality from the generic catalogue description.
  • Felimazole, Thyronorm and other named approved products are comparators, not the products identified by these rows. Their authorisations, formulation-specific evidence and handling instructions must not be transferred.
  • No calculator dose is published for this unidentified presentation. Confirm the actual product and current label before prescribing; equal ingredient, strength and form do not prove pharmaceutical or dose-delivery equivalence.
  • Thiamazole controls thyroid-hormone production but is not curative. Discuss definitive treatment options and reassess the long-term plan for the individual cat.
  • Obtain baseline and serial clinical status, body weight, TT4, CBC, chemistry, blood pressure and renal assessment; titrate to the lowest effective exact-label regimen and investigate adverse changes promptly.
  • Restoring euthyroidism can unmask or worsen renal dysfunction. Evaluate renal status and perfusion before and during titration rather than withholding all treatment automatically.
  • Primary hepatic disease, important haematologic/coagulation or autoimmune disorders, diabetes, pregnancy/lactation and hypersensitivity carry major restrictions in named labels; the exact current product label and patient status must be checked.
  • Review phenobarbital, benzimidazole anthelmintics, anticoagulants and medicines whose required dose can change after euthyroidism. Do not assume the interaction section is identical across unidentified products.
  • Thiamazole is a human reproductive/occupational hazard. Use gloves and follow the exact leaflet for tablets, solution, spills, vomit and used litter; pregnant or potentially pregnant handlers require particular protection.
  • Do not transfer Thyronorm claims about the oral syringe, administration with food, storage or in-use period until this 5 mg/ml solution is exactly identified.
Assessment sources
  1. Thiamazole product identity audit2026
  2. Felimazole 2.5 mg comparator SPC2026
  3. Thyronorm 5 mg/ml comparator SPC2026
  4. FDA Felimazole approval record2026
  5. FDA approved generic bioequivalence2025
  6. AAFP feline hyperthyroidism guideline2016
  7. Current VMD thiamazole product list2026
Assessed: 22 Oct 2026No axis or overall score is shown when the available evidence does not support a responsible numerical assessment.
Composition / strength
Methimazole5 mg/ml
Formulation Type
Solution
Administration route
By mouth
Manufacturer
-
Product
generic presentation, not registered in Georgia under a trade name
Registration
Georgia Unknown EU Not confirmed
Verified on: 22 Oct 2026
 UK Not confirmed
Verified on: 22 Oct 2026
 US Not confirmed
Verified on: 22 Oct 2026
Controlled in Georgia
No
Checked against the narcotics law, Annex 1, lists I-IV, and Order No. 22/n.
Verified on: 16 Oct 2026
Information not fully verified No exact-product dose is published. Thyronorm, Felimazole solution and other named 5 mg/ml products are distinct authorised comparators, not the product identified by this row. Confirm the trade name, manufacturer/MA holder, authorisation, pack, dispenser and current label before using a product-specific volume, food instruction, storage or in-use period.

Professional reference for veterinary professionals. Not advertising and not a substitute for the product label/SPC.

For veterinary professionals only. It does not replace clinical judgement or the product label; check the dose in the official label (SPC). vetman is not liable for harm caused by using this information.

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This reference is still growing. Missing a product? Let us know. · Report an error or request an addition · Updated: 23 Oct 2026

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