Levothyroxine Wockhardt Uk (Levothyroxine Sodium)

Levothyroxine is a synthetic thyroid hormone used to manage disorders of thyroid hormone deficiency.

• Hypothyroidism: restores normal thyroid hormone levels and alleviates symptoms such as fatigue, weight gain, and cold intolerance.
• Thyroid hormone replacement after thyroidectomy: provides the necessary hormone to maintain metabolic function following surgical removal of the thyroid gland.
• Goiter: helps reduce gland enlargement by normalizing thyroid hormone feedback mechanisms.

• Levothyroxine sodium is a synthetic form of the endogenous hormone thyroxine (T4). After oral absorption, it is converted to the active hormone triiodothyronine (T3) within peripheral tissues. The hormone binds to nuclear thyroid hormone receptors, regulating gene transcription that controls basal metabolic rate, protein synthesis, and growth. By replacing deficient hormone, it normalizes metabolic activity and restores physiological homeostasis.

Levothyroxine can cause a range of adverse reactions, from mild to serious. Monitoring and prompt reporting of symptoms are recommended.

Common Side Effects

• Headache: mild to moderate discomfort often reported during dose adjustments.
• Insomnia: difficulty falling or staying asleep, especially with higher doses.
• Palpitations: sensation of rapid or irregular heartbeat.
• Weight loss: unintended loss of body weight due to increased metabolism.
• Heat intolerance: feeling unusually warm or sweaty.
• Tremor: fine shaking of the hands or fingers.

Serious or Rare Side Effects

• Chest pain: may indicate cardiac ischemia and requires immediate evaluation.
• Arrhythmia: abnormal heart rhythms, potentially life‑threatening.
• Severe allergic reaction: rash, itching, swelling, or difficulty breathing.
• Osteoporosis: reduced bone mineral density with long‑term overtreatment.
• Adrenal insufficiency: exacerbation of underlying adrenal disorders.
• Myopathy: muscle pain or weakness, particularly in the elderly.

Levothyroxine therapy requires careful clinical oversight to avoid over‑ or under‑replacement.

• Dose titration: adjust dose based on serial TSH and free T4 measurements.
• Cardiovascular disease: initiate at lower doses and monitor for angina or arrhythmias.
• Elderly patients: start with reduced doses to prevent cardiac stress.
• Pregnancy and lactation: use only if clearly indicated and under physician supervision.
• Drug interactions: review concomitant medications that may affect absorption or hormone levels.
• Store at ambient temperature below 25°C: keep in the original pack, protect from moisture.

Levothyroxine absorption and activity can be altered by several co‑administered agents.

Major Interactions (Avoid)

• Antacids containing aluminum or magnesium: bind levothyroxine and reduce absorption.
• Calcium supplements: form insoluble complexes that diminish bioavailability.
• Iron preparations: interfere with intestinal uptake of the hormone.
• Cholestyramine and other bile‑acid sequestrants: decrease absorption by binding the drug.
• Sucralfate: chelates levothyroxine, markedly reducing its effectiveness.

Moderate Interactions (Monitor Closely)

• Amiodarone: may alter thyroid hormone metabolism and require dose adjustment.
• Estrogen therapy or oral contraceptives: can increase thyroid‑binding globulin, affecting hormone levels.
• Rifampin: induces hepatic enzymes, potentially increasing hormone clearance.
• Carbamazepine: enhances metabolism leading to reduced efficacy.
• Beta‑blockers: may mask symptoms of overtreatment such as tachycardia.