Levothyroxine Sodium Unifarma (Levothyroxine Sodium)

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

• Hypothyroidism: restores normal thyroid hormone levels and alleviates symptoms such as fatigue, weight gain, and cold intolerance.
• Goiter: reduces thyroid gland enlargement by normalizing circulating hormone levels.
• Post‑thyroidectomy or radioactive iodine therapy: provides necessary hormone replacement to maintain metabolic balance.

• Levothyroxine Sodium is a synthetic form of the endogenous hormone thyroxine (T4). After oral absorption, it is converted to the active hormone triiodothyronine (T3) in peripheral tissues, binding to nuclear thyroid hormone receptors and modulating gene transcription that regulates basal metabolic rate, protein synthesis, and growth. This restores normal endocrine function in patients with insufficient endogenous thyroid hormone production.

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

Common Side Effects

• Headache: mild to moderate pain in the head region.
• Insomnia: difficulty initiating or maintaining sleep.
• Palpitations: sensation of rapid or irregular heartbeat.
• Weight loss: unintended reduction in body weight.
• Heat intolerance: increased sensitivity to warm environments.
• Tremor: fine shaking of the hands or other muscles.

Serious or Rare Side Effects

• Chest pain: possible indication of cardiac ischemia.
• Arrhythmia: abnormal heart rhythm that may require medical attention.
• Severe hyperthyroidism: symptoms of excessive thyroid activity such as anxiety, sweating, and rapid weight loss.
• Allergic reaction: rash, itching, swelling, or difficulty breathing.
• Bone loss: accelerated osteoporosis with long‑term overtreatment.
• Angina: chest discomfort due to reduced blood flow to the heart.

Levothyroxine Sodium requires careful monitoring and individualized dosing.

• Dose adjustment: titrate based on regular TSH and free T4 measurements.
• Cardiovascular disease: use caution in patients with angina, arrhythmias, or recent myocardial infarction.
• Pregnancy: risk category unknown; assess benefits versus potential risks.
• Elderly patients: initiate therapy at lower doses to avoid overtreatment.
• Drug interactions: review concomitant medications that may affect absorption or metabolism.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

Levothyroxine Sodium can interact with several medicines, altering its effectiveness or safety.

Major Interactions (Avoid)

• Antacids containing aluminum or magnesium: reduce levothyroxine absorption.
• Calcium supplements: bind levothyroxine and decrease bioavailability.
• Iron preparations: impair absorption when taken concurrently.
• Warfarin: may enhance anticoagulant effect, requiring INR monitoring.
• Amiodarone: can cause thyroid dysfunction and affect levothyroxine dosing.

Moderate Interactions (Monitor Closely)

• Statins: possible increased risk of myopathy.
• Beta‑blockers: may mask symptoms of hyperthyroidism.
• Oral contraceptives: may increase levothyroxine binding proteins.
• SSRIs: potential for altered thyroid hormone levels.
• Diabetes medications: thyroid status can influence glucose control.