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Active substance

Levothyroxine

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Thyroid hormone (synthetic T4). No registration in force in Georgia. Forms: scored tablet, solution.

Dose and use

Doses

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

Active substance Levothyroxine
Dose calculatorCalculates the active-substance amount; it is not a prescription.
PatientSpecies and weight will be filled in automatically in other calculators.
Selected dose
Dose Species Indication Route Frequency Source
10–40 mcg/kg Dog Hypothyroidism By mouth once daily
VMD SPC 2025
Official product label (SPC), VMD, UK
Approved by the UK Veterinary Medicines Directorate (VMD) as part of the product's authorisation. It applies to that product as authorised there.
Leventa 1 mg/ml Oral Solution for Dogs - Summary of Product Characteristics
UK Veterinary Medicines Directorate, 2025
22–44 mcg/kg Dog Hypothyroidism By mouth total daily dose
VMD SPC 2010
Official product label (SPC), VMD, UK
Approved by the UK Veterinary Medicines Directorate (VMD) as part of the product's authorisation. It applies to that product as authorised there.
Soloxine 0.2 mg Tablet - Summary of Product Characteristics
UK Veterinary Medicines Directorate, 2010
20 mcg/kg Dog, Cat Hypothyroidism By mouth total daily dose, given once or divided into 2 doses
Thyroxanil 200 µg, VMD SPC 2021
Official product label (SPC), VMD, UK
Approved by the UK Veterinary Medicines Directorate (VMD) as part of the product's authorisation. It applies to that product as authorised there.
Thyroxanil 200 microgram tablets for dogs and cats - Summary of Product Characteristics
UK Veterinary Medicines Directorate, 2021
10 mcg/kg Dog Hypothyroidism By mouth 2 times daily
VMD SPC 2025
Official product label (SPC), VMD, UK
Approved by the UK Veterinary Medicines Directorate (VMD) as part of the product's authorisation. It applies to that product as authorised there.
Thyforon flavoured 200 microgram tablets for dogs - Summary of Product Characteristics
UK Veterinary Medicines Directorate, 2025
22 mcg/kg Dog Hypothyroidism By mouth total daily dose, given once or divided into 2 doses
FDA 2023
Official product label (SPC), FDA, US
Approved by the US Food and Drug Administration (FDA) as part of the product's authorisation. It applies to that product as authorised there.
Thyro-Tabs Canine (levothyroxine sodium tablets) - package insert
FDA (NADA 141-448), DailyMed, 2023
22 mcg/kg Dog Hypothyroidism By mouth 2 times daily
FDA 2021
Official product label (SPC), FDA, US
Approved by the US Food and Drug Administration (FDA) as part of the product's authorisation. It applies to that product as authorised there.
ThyroKare (levothyroxine sodium tablets) - Freedom of Information Summary
FDA (NADA 141-539), 2021
22 mcg/kg
off-label
 Cat Hypothyroidism By mouth total daily dose, given once or divided into 2 doses
MSD Vet Manual 2025
Reference book
A veterinary reference written and reviewed by specialists, summarising accepted practice. The product label gives the authorised dose.
Hypothyroidism in Animals
MSD/Merck Veterinary Manual, 2025
Before use

Safety information

Known Contraindications

  • Critical
    Do not use levothyroxine in dogs with uncorrected hypoadrenocorticism. Stabilise glucocorticoid and mineralocorticoid replacement first, then start levothyroxine at 25% of the usual dose and increase by 25% every 2 weeks as needed.
    Sources: Product label
  • Critical
    Do not use levothyroxine in animals with hyperthyroidism or thyrotoxicosis.
  • Critical
    Known hypersensitivity to levothyroxine or any excipient is a contraindication.
  • Warning
    Levothyroxine can stress a poorly functioning heart and precipitate decompensation or congestive heart failure. In patients with cardiac disease, start at 25% of the usual dose and increase by 25% every 2 weeks until stable.
  • Caution
    Levothyroxine can alter insulin requirements in diabetic patients. Start cautiously, monitor glycaemic control, and adjust insulin as needed.
  • Caution
    Product information on levothyroxine use during pregnancy is inconsistent: some products permit it, while others have not established safety. If treatment is necessary, use the selected product’s guidance and monitor thyroid status regularly because dose requirements can change.
  • Caution
    Product information on levothyroxine use during lactation is inconsistent: some products permit it, while others have not established safety. Use the selected product’s guidance and monitor the patient when treatment is necessary.

Known Drug Interactions

  • Minor warning Levothyroxine + Calcium Carbonate
    Antacids containing aluminium, magnesium, or calcium, as well as ferrous sulfate and sucralfate, can reduce levothyroxine absorption.
    Recommendation: Separate levothyroxine from antacids, iron, or sucralfate by at least 2 hours.
  • Minor warning Levothyroxine + Ferrous sulfate
    Antacids containing aluminium, magnesium, or calcium, as well as ferrous sulfate and sucralfate, can reduce levothyroxine absorption.
    Recommendation: Separate levothyroxine from antacids, iron, or sucralfate by at least 2 hours.
  • Minor warning Levothyroxine + Insulin glargine
    Starting or changing levothyroxine supplementation in a diabetic dog receiving insulin can alter the insulin requirement.
    Recommendation: Monitor glycaemic control frequently when starting levothyroxine.
  • Minor warning Levothyroxine + Insulin human
    Starting or changing levothyroxine supplementation in a diabetic dog receiving insulin can alter the insulin requirement.
    Recommendation: Monitor glycaemic control frequently when starting levothyroxine.
  • Minor warning Sucralfate + Levothyroxine
    Antacids containing aluminium, magnesium, or calcium, as well as ferrous sulfate and sucralfate, can reduce levothyroxine absorption.
    Recommendation: Separate levothyroxine from antacids, iron, or sucralfate by at least 2 hours.
  • Minor warning Furosemide + Levothyroxine
    Several drugs, including barbiturates, antacids, anabolic steroids, diazepam, and furosemide, can alter thyroid-hormone binding or metabolism and may affect the response to levothyroxine.
    Recommendation: Recheck T4 and adjust the dose as needed.
  • Minor warning Levothyroxine + Magnesium Carbonate
    Antacids containing aluminium, magnesium, or calcium, as well as ferrous sulfate and sucralfate, can reduce levothyroxine absorption.
    Recommendation: Separate levothyroxine from antacids, iron, or sucralfate by at least 2 hours.
  • Minor warning Levothyroxine + Phenobarbital
    Several drugs, including barbiturates, antacids, anabolic steroids, diazepam, and furosemide, can alter thyroid-hormone binding or metabolism and may affect the response to levothyroxine.
    Recommendation: Recheck T4 and adjust the dose as needed.
Latin name
Levothyroxine
Georgian name
ლევოთიროქსინი
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
Products
Leventa, Thyroxanil
Human medicines in Georgia
Euthyrox, L-Thyroxin, L-Thyroxin ARISTO, L-thyroxine Henning inject, Tezarin
Human medicines with this substance in the Georgian register of medicines (Ministry of Health), checked on 18 Oct 2026. They are human medicines, not veterinary products; strengths and forms differ.
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).

Leventa, Solution

Levothyroxine sodium 1 mg/ml, oral solution for dogs
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.
Dog
8.4/10
Very good
vetman assessment

Leventa

Levothyroxine sodium 1 mg/ml, oral solution for dogs
Assessed clinical scopeDog · Long-term thyroid-hormone replacement for confirmed hypothyroidism · By mouth
Care settingVeterinarian-directed lifelong replacement after diagnostic confirmation, with response-led dose titration and serial thyroid monitoring
vetman score 8.4/10 Very good
Evidence confidence: High Georgia: No · Verified on 22 Oct 2026

An exact, evidence-supported canine liquid with fine dose adjustment; strong when diagnosis, food timing and T4-led titration are controlled.

Regulatory and scientific credibility9.0/10

Exact current GB and European authorisations identify the product, MA holder, species, strength, form and label. Georgia has no exact registration; US positives are different products.

Clinical efficacy8.5/10

Exact-product PK and clinical data support once-daily liquid replacement in hypothyroid dogs, with individual response-led adjustment.

Safety and tolerability7.5/10

Therapy is titratable and established, but uncorrected adrenal insufficiency, cardiac disease, over-replacement and drug interactions require diagnosis, staged dosing and monitoring.

Clinical practicality8.5/10

The 0.05 ml syringe supports fine adjustment; once-daily dosing is convenient. Refrigeration, food timing and the six-month broached life are material but manageable.

Full-course cost-effectiveness-

Current exact Georgian price/availability and a comparable treatment-period cost are not verified; cost is excluded.

Important safety and use flags

  • Confirm hypothyroidism with compatible clinical findings and appropriate thyroid testing; a low T4 during non-thyroidal illness or drug exposure is not sufficient by itself.
  • This rating is exact-product specific. Thyroxanil tablet and Leventa solution differ in formulation, bioavailability, starting regimen, food instruction, pack and monitoring; do not convert blindly between them.
  • Leventa is for dogs only. Give consistently 2–3 hours before food; concurrent food materially reduces/delays absorption. Use the supplied 0.05 ml syringe, refrigerate and discard six months after opening.
  • Clinical improvement and T4 response guide titration; recheck after starting or each dose change. Lifelong therapy should not continue on an unconfirmed diagnosis merely because nonspecific signs improve.
  • Do not use with uncorrected adrenal insufficiency. Thyroid replacement can increase metabolic and cardiac demand; stabilize concurrent disease and introduce cautiously where cardiovascular disease is present.
  • Over-replacement causes thyrotoxicosis: restlessness, tachycardia, panting, polydipsia/polyuria, weight loss, polyphagia and heat intolerance. Reduce/withhold and reassess dose and diagnosis if these appear.
  • Monitor clinical response and appropriately timed T4; consider TSH and routine laboratory/cardiovascular assessment when indicated. Sample timing must match the exact product’s label.
  • Phenobarbital, antacids, furosemide and other medicines can alter thyroid-hormone binding, absorption or metabolism. Review interacting drugs and interpret thyroid tests in that context.
  • The solution permits fine volume adjustment, but only after accurate weighing and response-led titration. Do not substitute a tablet dose-volume conversion without accounting for formulation-specific bioavailability.
  • Exact Thyroxanil and Leventa are authorised in GB/European jurisdictions but not registered in Georgia. US Thyro-Tabs is a distinct dog-only tablet and does not confer US approval on either exact product.
Assessment sources
  1. VMD SPC 20252025
  2. Leventa VMD record2026
  3. Leventa UPD record2026
  4. Leventa formulation PK2008
  5. Leventa clinical PK/efficacy2014
  6. Canine levothyroxine pivotal study2018
  7. MSD Vet Manual 20252025
  8. GE levothyroxine register audit2026
Assessed: 22 Oct 2026The overall score uses 25/25/25/15/10 weights. An unassessed price is excluded and the remaining weights are proportionally renormalised.
Composition / strength
Levothyroxine1 mg/ml
Formulation Type
Solution
Administration route
By mouth
Manufacturer
Intervet International B.V. · Netherlands
Registration
Georgia No
Not registered in Georgia
Veterinary (National Food Agency)
Verified on: 22 Oct 2026
 EU Yes, veterinary
№ IE/V/0182/001
Verified on: 22 Oct 2026
 UK Yes, veterinary
№ Vm 06376/5058
Verified on: 22 Oct 2026
 US No
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 Exact 30 ml refrigerated oral solution supplied with a 0.05 ml graduated syringe. Start and titrate only per the current label and clinical/T4 response; administer consistently 2–3 hours before food. Use within six months after opening.

Thyroxanil 0.2 mg, Scored tablet

Levothyroxine sodium 200 microgram, tablet for dogs and 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.
Dog Long-term thyroid-hormone replacement for confirmed hypothyroidism
8.3/10
Very good
vetman assessment

Thyroxanil

Levothyroxine sodium 200 microgram, tablet for dogs and cats
Assessed clinical scopeDog · Long-term thyroid-hormone replacement for confirmed hypothyroidism · By mouth
Care settingVeterinarian-directed lifelong replacement after diagnostic confirmation, with response-led dose titration and serial thyroid monitoring
vetman score 8.3/10 Very good
Evidence confidence: High Georgia: No · Verified on 22 Oct 2026

An exact authorised quarterable canine tablet with strong replacement evidence; reliable when diagnosis, feeding consistency and serial T4 monitoring are correct.

Regulatory and scientific credibility9.0/10

Exact current GB and European authorisations identify the product, MA holder, species, strength, form and label. Georgia has no exact registration; US positives are different products.

Clinical efficacy8.5/10

Exact authorised indication and substantial canine replacement evidence support tablet efficacy when diagnosis and monitoring are correct.

Safety and tolerability7.5/10

Therapy is titratable and established, but uncorrected adrenal insufficiency, cardiac disease, over-replacement and drug interactions require diagnosis, staged dosing and monitoring.

Clinical practicality8.0/10

Quartering provides 50 microgram steps and once-daily or divided dosing is possible; feeding consistency and post-dose sampling still require discipline.

Full-course cost-effectiveness-

Current exact Georgian price/availability and a comparable treatment-period cost are not verified; cost is excluded.

Important safety and use flags

  • Confirm hypothyroidism with compatible clinical findings and appropriate thyroid testing; a low T4 during non-thyroidal illness or drug exposure is not sufficient by itself.
  • This rating is exact-product specific. Thyroxanil tablet and Leventa solution differ in formulation, bioavailability, starting regimen, food instruction, pack and monitoring; do not convert blindly between them.
  • Thyroxanil may be divided into halves or quarters, not arbitrary crumbs. Keep administration relative to food consistent and use the exact label’s sampling time after dosing.
  • Clinical improvement and T4 response guide titration; recheck after starting or each dose change. Lifelong therapy should not continue on an unconfirmed diagnosis merely because nonspecific signs improve.
  • Do not use with uncorrected adrenal insufficiency. Thyroid replacement can increase metabolic and cardiac demand; stabilize concurrent disease and introduce cautiously where cardiovascular disease is present.
  • Over-replacement causes thyrotoxicosis: restlessness, tachycardia, panting, polydipsia/polyuria, weight loss, polyphagia and heat intolerance. Reduce/withhold and reassess dose and diagnosis if these appear.
  • Monitor clinical response and appropriately timed T4; consider TSH and routine laboratory/cardiovascular assessment when indicated. Sample timing must match the exact product’s label.
  • Phenobarbital, antacids, furosemide and other medicines can alter thyroid-hormone binding, absorption or metabolism. Review interacting drugs and interpret thyroid tests in that context.
  • A 200 microgram tablet quarters to 50 micrograms. Use only intact label-supported halves/quarters and select another strength/form when the required dose cannot be measured reliably.
  • Exact Thyroxanil and Leventa are authorised in GB/European jurisdictions but not registered in Georgia. US Thyro-Tabs is a distinct dog-only tablet and does not confer US approval on either exact product.
Assessment sources
  1. Thyroxanil 200 µg, VMD SPC 20212021
  2. Thyroxanil VMD record2026
  3. Thyroxanil UPD record2026
  4. Canine levothyroxine pivotal study2018
  5. MSD Vet Manual 20252025
  6. GE levothyroxine register audit2026
Assessed: 22 Oct 2026The overall score uses 25/25/25/15/10 weights. An unassessed price is excluded and the remaining weights are proportionally renormalised.
Cat Long-term thyroid-hormone replacement for confirmed hypothyroidism
7.3/10
Good
vetman assessment

Thyroxanil

Levothyroxine sodium 200 microgram, tablet for dogs and cats
Assessed clinical scopeCat · Long-term thyroid-hormone replacement for confirmed hypothyroidism · By mouth
Care settingVeterinarian-directed lifelong replacement after diagnostic confirmation, with response-led dose titration and serial thyroid monitoring
vetman score 7.3/10 Good
Evidence confidence: Medium Georgia: No · Verified on 22 Oct 2026

A rare but exact on-label feline option with reasonable replacement evidence; dose-unit limits and the smaller feline evidence base keep it below the canine score.

Regulatory and scientific credibility9.0/10

Exact current GB and European authorisations identify the product, MA holder, species, strength, form and label. Georgia has no exact registration; US positives are different products.

Clinical efficacy7.0/10

The exact label authorises cats and guidelines/recent cohorts support replacement, but naturally occurring feline disease is rare and product-specific feline evidence is smaller.

Safety and tolerability6.5/10

Therapy is titratable but feline diagnostic uncertainty, renal context and limited PK require careful lifelong monitoring; over-replacement can cause thyrotoxicosis.

Clinical practicality6.5/10

Quartering gives 50 microgram steps, but the label warns that dosing below 2.5 kg may be inaccurate and many cats need individual dose/frequency adjustment.

Full-course cost-effectiveness-

Current exact Georgian price/availability and a comparable treatment-period cost are not verified; cost is excluded.

Important safety and use flags

  • Confirm hypothyroidism with compatible clinical findings and appropriate thyroid testing; a low T4 during non-thyroidal illness or drug exposure is not sufficient by itself.
  • This rating is exact-product specific. Thyroxanil tablet and Leventa solution differ in formulation, bioavailability, starting regimen, food instruction, pack and monitoring; do not convert blindly between them.
  • Thyroxanil may be divided into halves or quarters, not arbitrary crumbs. Keep administration relative to food consistent and use the exact label’s sampling time after dosing.
  • Naturally occurring feline hypothyroidism is rare. Confirm repeatable low T4 with elevated TSH and compatible signs; distinguish congenital, spontaneous and post-treatment iatrogenic disease before lifelong therapy.
  • Do not use with uncorrected adrenal insufficiency. Thyroid replacement can increase metabolic and cardiac demand; stabilize concurrent disease and introduce cautiously where cardiovascular disease is present.
  • Over-replacement causes thyrotoxicosis: restlessness, tachycardia, panting, polydipsia/polyuria, weight loss, polyphagia and heat intolerance. Reduce/withhold and reassess dose and diagnosis if these appear.
  • Monitor T4, TSH, clinical response, body weight and renal variables. Correcting overt hypothyroidism may improve azotaemia, but renal trends and prior hyperthyroidism treatment must be interpreted together.
  • Phenobarbital, antacids, furosemide and other medicines can alter thyroid-hormone binding, absorption or metabolism. Review interacting drugs and interpret thyroid tests in that context.
  • A 200 microgram tablet quarters to 50 micrograms. The exact SPC warns dosing may be inaccurate below 2.5 kg; use an appropriate measurable formulation rather than inventing smaller fragments.
  • Exact Thyroxanil and Leventa are authorised in GB/European jurisdictions but not registered in Georgia. US Thyro-Tabs is a distinct dog-only tablet and does not confer US approval on either exact product.
Assessment sources
  1. Thyroxanil 200 µg, VMD SPC 20212021
  2. Thyroxanil VMD record2026
  3. Thyroxanil UPD record2026
  4. AAHA feline hypothyroidism 20232023
  5. Feline hypothyroidism cohort 20252025
  6. MSD Vet Manual 20252025
  7. GE levothyroxine register audit2026
Assessed: 22 Oct 2026The overall score uses 25/25/25/15/10 weights. An unassessed price is excluded and the remaining weights are proportionally renormalised.
Composition / strength
Levothyroxine0.2 mg
Formulation Type
Scored tablet
Administration route
By mouth
Manufacturer
Le Vet Beheer B.V.
Registration
Georgia No
Not registered in Georgia
Veterinary (National Food Agency)
Verified on: 22 Oct 2026
 EU Yes, veterinary
№ NL/V/0195/001
Verified on: 22 Oct 2026
 UK Yes, veterinary
№ Vm 41821/4031
Verified on: 22 Oct 2026
 US No
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 Exact cross-scored tablet; may be divided into halves or quarters (50 microgram steps). Starting treatment and sampling time must follow the current exact label and be titrated to clinical response and T4. Keep administration relative to food consistent; dosing under 2.5 kg may not be accurate.

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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