How do I decrease my Synthroid (levothyroxine) dose?

How to Decrease Synthroid (Levothyroxine) Dose

To decrease your Synthroid (levothyroxine) dose, reduce the current dose by 12.5-25 mcg increments every 4-6 weeks until the target TSH level is achieved, with TSH and free T4 monitoring 6-8 weeks after each dose adjustment. 1

Step-by-Step Approach to Decreasing Levothyroxine

1. Initial Dose Reduction:

   • For most adults: Decrease by 25 mcg from current dose
   • For elderly patients (>70 years) or those with coronary artery disease: Use smaller increments of 12.5 mcg 1

2. Monitoring Schedule:

   • Wait 6-8 weeks after dose adjustment before checking thyroid function tests
   • Check both TSH and free T4 levels 1
   • Target TSH range: 0.5-4.5 mIU/L for most patients with hypothyroidism

3. Further Adjustments:

   • If TSH remains below target range: Make additional 12.5-25 mcg reductions
   • Continue this process until optimal thyroid function is achieved
   • Once stabilized, monitor every 6-12 months 1

Special Considerations

Elderly Patients

• More sensitive to thyroid hormone changes
• Higher risk for cardiac complications
• Use more conservative dose reductions (12.5 mcg)
• May ultimately require significantly lower maintenance doses (50 mcg/day or less in some patients over 60) 2

Medication Timing and Interactions

• Continue taking levothyroxine on an empty stomach, 30-60 minutes before breakfast
• Maintain separation from medications that interfere with absorption:
  • Calcium and iron supplements: Take at least 4 hours apart
  • Antacids: Take at least 4 hours apart
  • Bile acid sequestrants: Take levothyroxine at least 1 hour before or 4-6 hours after 1

Common Pitfalls to Avoid

1. Decreasing too quickly: Abrupt large reductions can lead to hypothyroid symptoms
2. Insufficient monitoring: Always check thyroid function 6-8 weeks after any dose change
3. Ignoring symptoms: Watch for signs of under-replacement (fatigue, cold intolerance, weight gain) or over-replacement (palpitations, anxiety, insomnia)
4. Changing administration habits: Maintain consistent timing and conditions when taking the medication
5. Overlooking medication interactions: Continue to separate levothyroxine from interacting medications

When to Seek Medical Attention

• Development of new cardiac symptoms (palpitations, chest pain)
• Significant changes in energy levels, weight, or mental status
• Any concerning symptoms that develop after dose adjustment

Remember that levothyroxine has a narrow therapeutic index, and both underdosage and excessive dosage can cause adverse effects 3. Always make dose adjustments under medical supervision.