Product image of Levothyrox (Levothyroxine Sodium) supplied by GNH India

Levothyrox

Active Ingredient:
Levothyroxine Sodium
Origin:
EU

Levothyrox (Levothyroxine Sodium)

Levothyroxine sodium, the active ingredient in Levothyrox, is a thyroid hormone presented as an oral tablet for oral use. It replaces deficient thyroid hormone and is used to treat hypothyroidism and related thyroid conditions. Levothyrox provides exogenous T4 to restore normal metabolic activity in patients with thyroid hormone deficiency.

GNH India supplies Levothyrox as a licensed, GDP‑compliant international pharmaceutical supplier serving hospitals, pharmacies and clinics worldwide.

Manufacturer / TM Owner

Merck Santé S.A.S.

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Indications & Clinical Uses

  • Levothyrox acts on the thyroid hormone pathway to normalize hormone levels in several thyroid disorders.
  • Primary hypothyroidism: restores normal thyroid hormone concentrations and metabolic rate.
  • Secondary (central) hypothyroidism: supplies needed T4 when pituitary stimulation is insufficient.
  • Goiter: reduces gland size by normalizing hormone feedback.
  • Thyroid cancer (adjuvant therapy): provides hormone replacement after thyroidectomy to support metabolism.

How It Works

  • Levothyroxine sodium is a synthetic form of the endogenous hormone thyroxine (T4). After oral absorption, it enters the bloodstream and is converted to the active hormone triiodothyronine (T3) within target tissues. Both T4 and T3 bind to nuclear thyroid hormone receptors, modulating gene transcription that regulates basal metabolic rate, protein synthesis, and growth. By supplying exogenous hormone, Levothyrox compensates for deficient endogenous production.

Side Effects

Levothyrox may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

  • Headache: mild to moderate intensity.
  • Insomnia: difficulty falling or staying asleep.
  • Palpitations: sensation of rapid or irregular heartbeat.
  • Weight loss: unintended reduction in body weight.
  • Diarrhea: loose stools or increased bowel movements.

Serious or Rare Side Effects

  • Cardiac arrhythmia: potentially life‑threatening rhythm disturbances.
  • Hyperthyroidism symptoms: heat intolerance, tremor, anxiety.
  • Bone loss: increased risk of osteoporosis with long‑term overtreatment.
  • Allergic reaction: rash, itching, swelling, or anaphylaxis.
  • Myocardial infarction: rare but possible in susceptible individuals.

Precautions & Warnings

  • Levothyrox should be used with careful clinical monitoring and patient education.
  • Dose titration: adjust based on thyroid function tests and clinical response.
  • Cardiovascular disease: evaluate heart status before initiating therapy.
  • Pregnancy and lactation: assess risk‑benefit ratio under medical supervision.
  • Elderly patients: start with lower doses and monitor closely.
  • Store at ambient temperature: keep below 25 °C, retain in original container, protect from moisture and light.

Avoid Interactions

Levothyrox can interact with several medicines, affecting its absorption or action.

Major Interactions (Avoid)

  • Levothyroxine + amiodarone: may cause severe thyroid dysfunction.
  • Levothyroxine + insulin: increased risk of hypoglycemia.

Moderate Interactions (Monitor Closely)

  • Levothyroxine + calcium or iron supplements: reduce levothyroxine absorption; separate dosing by at least 4 hours.
  • Levothyroxine + proton pump inhibitors: may modestly decrease absorption; monitor thyroid levels.
  • Levothyroxine + warfarin: may enhance anticoagulant effect; check INR regularly.

Frequently Asked Questions

Levothyrox is prescribed for primary and secondary (central) hypothyroidism, for managing goiter, and as an adjunct in thyroid cancer treatment after thyroidectomy. It supplies the missing thyroid hormone to restore normal metabolic function in these conditions.

Levothyroxine sodium is a synthetic form of thyroxine (T4). After oral absorption, it is converted to the active hormone triiodothyronine (T3) within cells. Both hormones bind to nuclear thyroid receptors, regulating gene expression that controls metabolism, growth, and development.

The dose of Levothyrox is individualized. A qualified prescriber determines the appropriate amount based on the patient’s age, weight, severity of hormone deficiency, and thyroid function test results. Dosage adjustments are made during follow‑up visits.

Levothyrox is generally considered safe in pregnancy and lactation when medically indicated, as untreated hypothyroidism can harm both mother and fetus. However, therapy should be guided by a healthcare professional who will monitor thyroid levels and adjust dosing as needed.

To place an order, submit an enquiry on the Levothyrox product page at gnhindia.com, specifying the required quantity. GNH India works with hospitals, pharmacies, and procurement teams worldwide, verifies trade or institutional credentials, and then provides pricing, availability, shipping details, and any necessary import documentation.

Levothyrox provides pure T4, relying on the body’s conversion to T3, whereas combination products contain both T4 and T3. Levothyrox is often preferred for its stable pharmacokinetic profile and ease of dose titration, but individual response may vary, and some patients may benefit from combined therapy under specialist guidance.

Levothyrox tablets should be stored at ambient temperature, preferably below 25 °C. Keep them in the original packaging to protect from moisture and light, and store them out of reach of children.

Levothyrox is taken orally, usually on an empty stomach 30‑60 minutes before breakfast. Swallow the tablet whole with a full glass of water. Consistency in timing and relation to meals helps maintain stable blood levels.

Serious risks include cardiac arrhythmias, especially in patients with underlying heart disease, symptoms of overt hyperthyroidism such as tremor and anxiety, and rare cases of severe allergic reactions. Regular monitoring of thyroid function and cardiac status helps mitigate these risks.

Levothyrox is contraindicated in patients with untreated adrenal insufficiency, acute myocardial infarction, or known hypersensitivity to levothyroxine or any excipients. Individuals with these conditions should avoid the medication unless a physician determines it is absolutely necessary.

Published by

GNH India Pharmaceuticals Limited

Licensed pharmaceutical supplier

Last updated:

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