What is the recommended dosing for supplemental adrenal corticoid (adrenal cortex hormone) therapy in patients with hypothyroidism and suspected or confirmed adrenal insufficiency?

Supplemental Adrenal Corticoid Therapy Dosing in Hypothyroidism with Adrenal Insufficiency

For patients with hypothyroidism and adrenal insufficiency, the recommended dosing for supplemental adrenal corticoid therapy is hydrocortisone 15-25 mg daily in divided doses (typically 10-20 mg in the morning and 5-10 mg in early afternoon) along with fludrocortisone 0.1 mg daily for mineralocorticoid replacement. 1

Initial Replacement Therapy

Glucocorticoid Replacement

• Primary replacement:
  • Hydrocortisone: 15-25 mg daily in divided doses
    • Morning dose: 10-20 mg (2/3 of total daily dose)
    • Afternoon dose: 5-10 mg (1/3 of total daily dose) taken early afternoon 2, 1
  • Timing is important to mimic natural cortisol rhythm (highest in morning, lowest at midnight)

Mineralocorticoid Replacement

• Fludrocortisone: 0.1 mg daily (for primary adrenal insufficiency)
  • Dosage range: 0.1 mg three times weekly to 0.2 mg daily 3
  • Reduce to 0.05 mg daily if transient hypertension develops 3
  • Not typically needed in secondary adrenal insufficiency

Critical Considerations

1. Always start corticosteroids before thyroid hormone replacement in patients with both conditions to prevent precipitating adrenal crisis 2
2. Distinguish between primary and secondary adrenal insufficiency:
   • Primary: High ACTH, low cortisol, electrolyte abnormalities (↓Na, ↑K)
   • Secondary: Low ACTH, low cortisol, usually normal electrolytes 1

Stress Dosing Protocol

Patients must be educated on stress dosing to prevent adrenal crisis:

• Minor illness/stress: Double or triple usual daily dose 1
• Moderate stress: Hydrocortisone 50-75 mg/day in divided doses 1
• Severe stress/surgery: Hydrocortisone 100 mg IV immediately, followed by 100-300 mg/day as continuous infusion or divided doses every 6 hours 2, 1
• Emergency treatment: For suspected adrenal crisis, administer hydrocortisone 100 mg IV immediately, followed by IV saline infusion 1

Patient Education and Monitoring

• All patients need:
  • Medical alert bracelet or necklace for adrenal insufficiency 2, 1
  • Education on stress dosing for sick days 2
  • Emergency hydrocortisone injection kit 1
  • Regular follow-up with endocrinology 2

Monitoring Parameters

• Blood pressure and electrolytes (particularly in primary adrenal insufficiency)
• Weight changes
• Clinical symptoms of over-replacement (weight gain, hypertension, edema)
• Clinical symptoms of under-replacement (fatigue, nausea, hypotension)
• Plasma renin activity (for mineralocorticoid adjustment) 1

Special Considerations

• DHEA replacement (25-50 mg daily) may be considered for persistent symptoms despite adequate primary replacement therapy, particularly in women with low libido or energy 2, 1
• Endocrinology consultation is recommended for all patients with adrenal insufficiency, especially before surgery or other stressful procedures 2
• Patients on chronic corticosteroid therapy are at risk for glucocorticoid-induced adrenal insufficiency, which requires careful tapering when discontinuing 4

Common Pitfalls

• Failing to start corticosteroid replacement before thyroid hormone replacement, which can precipitate adrenal crisis 2
• Inadequate stress dosing during illness, surgery, or trauma 1
• Missing the diagnosis of concurrent adrenal insufficiency in hypothyroid patients (occurs in approximately 12% of critically ill patients) 5
• Insufficient patient education about stress dosing and emergency management 2, 1
• Failure to provide medical alert identification 1

Remember that both under-replacement and over-replacement of glucocorticoids can lead to significant morbidity and mortality, making proper dosing and patient education essential components of management 6.