What is the treatment for hypothyroidism (elevated Thyroid-Stimulating Hormone (TSH))?

Treatment for Hypothyroidism (Elevated TSH)

Levothyroxine is the standard first-line treatment for hypothyroidism, with dosing based on TSH levels, patient age, and comorbidities. 1

Diagnosis Confirmation

• Confirm hypothyroidism with repeat TSH and free T4 measurement within 2-3 months of initial assessment 2
• Evaluate for signs/symptoms of hypothyroidism, previous thyroid treatment, thyroid enlargement, family history of thyroid disease
• Consider checking thyroid antibodies (TPO) to identify autoimmune etiology 1

Treatment Algorithm

Initial Dosing

• For adults <70 years without cardiac disease: 1.6 mcg/kg/day based on ideal body weight 1
• For elderly patients or those with cardiac conditions: Start lower at 25-50 mcg/day 1
• For pregnant women: Adjust dose to restore TSH to reference range; requirements often increase during pregnancy 1, 3

Dose Titration

1. Check TSH after 6-8 weeks of treatment 1
2. Adjust dose in increments of 12.5-25 mcg based on TSH results 1
3. Target TSH ranges:
   • Most adults: 0.5-2.0 mIU/L 1
   • Elderly/cardiac patients: 1.0-4.0 mIU/L 1
   • Pregnant women: Trimester-specific reference range 3

Special Considerations

Subclinical Hypothyroidism Management

• TSH 4.5-10 mIU/L: Routine levothyroxine not recommended; monitor TSH every 6-12 months 2
  • Consider trial of levothyroxine if symptomatic, but benefits may be limited
• TSH >10 mIU/L: Levothyroxine therapy is reasonable 2
• Pregnancy or planning pregnancy: Treat subclinical hypothyroidism to restore TSH to reference range 2, 3

Administration Guidelines

• Take levothyroxine as single daily dose on empty stomach
• Take 30-60 minutes before breakfast or 3-4 hours after last meal 1
• Avoid taking with calcium, iron supplements, or medications that impair absorption 1

Monitoring

• Check TSH every 6-8 weeks during dose adjustment 1
• Once stable, monitor annually or sooner if clinical status changes 1
• For treated patients with persistent TSH elevation, evaluate:
  • Medication compliance (most common cause) 4
  • Absorption issues
  • Drug interactions
  • Inappropriate dosing

Potential Risks

• Overtreatment: Can lead to iatrogenic hyperthyroidism (14-21% of treated individuals) 2, 1

  • Decreased bone mineral density and increased fracture risk in older adults
  • Increased cardiovascular risk, including atrial fibrillation

• Undertreatment: Can lead to persistent hypothyroid symptoms 1

  • In children: adverse effects on cognitive development and linear growth 3

Alternative Treatments

• Combination T4/T3 therapy is not recommended as first-line treatment 1, 5
• Should only be considered after failure of optimized levothyroxine therapy 1
• Compounded T4/T3 formulations may lead to iatrogenic hypothyroidism if improperly dosed 5

Common Pitfalls

1. Failing to adjust dose despite abnormal TSH levels 6
2. Not accounting for pregnancy-related increased requirements 3
3. Overlooking drug interactions affecting levothyroxine absorption or metabolism
4. Using compounded thyroid hormones without proper monitoring 5
5. Overtreatment leading to subclinical hyperthyroidism and associated risks 2, 1

Remember that thyroid hormone replacement has a narrow therapeutic index, and both overtreatment and undertreatment can have significant clinical consequences 3.