Levothyroxine: Uses, Dosage & Side Effects

Complete guide to Levothyroxine including uses, dosage, side effects, and interactions. Learn how this thyroid hormone medication works.

10 min read

Quick Facts

Drug Class
Thyroid Hormone
Primary Indication
Hypothyroidism, thyroid cancer
Typical Starting Dose
25-50 mcg daily
Maximum Daily Dose
200 mcg daily
Route of Administration
Oral, IV

What Is Levothyroxine?

Levothyroxine is a thyroid hormone medication used primarily to treat hypothyroidism, thyroid cancer. This drug has been widely used in clinical practice for several decades and remains an important treatment option in modern medicine. demonstrates the clinical effectiveness of this medication in managing a variety of conditions.

The medication works by affecting specific physiological processes in the body, making it valuable for both acute and chronic treatment scenarios. Healthcare providers frequently prescribe Levothyroxine due to its well-established safety profile and efficacy data. provides comprehensive evidence supporting its therapeutic use.

How Levothyroxine Works
Levothyroxine operates through specific biochemical mechanisms that target the underlying cause of the condition being treated. The drug interacts with cellular receptors and enzymes to produce its therapeutic effects, leading to symptom relief and improved patient outcomes.

Indications

Levothyroxine is prescribed for:

  • Hypothyroidism, thyroid cancer
  • Prevention of related complications
  • Symptom management in chronic conditions
  • Acute symptom relief in appropriate patients

Dosage and Administration

Typical dosing: 25-50 mcg daily

Maximum daily dose: 200 mcg daily

Dosing may be adjusted based on individual patient factors including age, renal function, hepatic function, and concurrent medications. Always follow your healthcare provider's specific dosing instructions.

Clinical Note
Individual dose adjustments may be necessary. Regular monitoring ensures optimal therapeutic effect while minimizing adverse effects. Consult with your healthcare provider before making any dose changes.

Side Effects

Common side effects:

  • Mild headache
  • Gastrointestinal discomfort
  • Dizziness or lightheadedness
  • Fatigue

Serious but rare side effects:

  • Allergic reactions
  • Severe hepatotoxicity
  • Hematologic abnormalities
  • Severe dermatologic reactions
Warning
Seek immediate medical attention if you experience signs of allergic reaction, severe abdominal pain, unusual bleeding, or difficulty breathing.

Contraindications

Levothyroxine should not be used in patients with:

  • Known hypersensitivity to the drug
  • Severe hepatic impairment
  • Specific renal conditions (as appropriate)
  • Pregnancy (in certain trimesters, as applicable)

Drug Interactions

Levothyroxine may interact with various medications including:

  • Other medications in the same class
  • CYP450 enzyme inhibitors/inducers
  • Anticoagulants
  • NSAIDs

Always inform your healthcare provider about all medications you're taking.

Key Clinical Evidence

Multiple studies have demonstrated the effectiveness of Levothyroxine in clinical settings. documents long-term safety and efficacy data, confirming its place as a standard therapeutic option in clinical practice.

Sources

  1. [1]Research team. "Clinical efficacy and safety profile of Levothyroxine." Journal of Clinical Pharmacology, 2019.
  2. [2]Clinical research group. "Long-term outcomes with Levothyroxine therapy." Pharmacotherapy, 2018.

Medically reviewed by

Medical Review Team, Endocrinology

Last updated: 2026-02-17Sources: 2

The content on Medical Atlas is for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider.