What is the appropriate physiological steroid dosing regimen for a patient with Addison disease, including glucocorticoid and mineralocorticoid replacement?

Physiological Steroid Dosing in Addison Disease

For adults with Addison disease, start with hydrocortisone 15-25 mg daily divided into 2-3 doses (highest dose upon awakening), plus fludrocortisone 50-100 mcg daily. 1

Glucocorticoid Replacement

First-Line Therapy

• Hydrocortisone is the preferred glucocorticoid because it most closely mimics physiological cortisol 1, 2
• Dosing: 15-25 mg daily in adults, divided into 2-3 doses 1
  • Morning dose: Largest portion given immediately upon awakening
  • Two-dose regimen: Second dose in early afternoon (2 hours after lunch)
  • Three-dose regimen: Doses at morning, lunch, and afternoon
• Alternative: Cortisone acetate 20-35 mg daily in divided doses 1

Dosing Rationale

The recommended 15-25 mg daily dose exceeds actual physiological cortisol production (5-6 mg/m²) to account for oral bioavailability and absorption variability 2. While this may seem supraphysiological, it represents the minimum effective replacement dose in clinical practice.

Second-Line Options

• Prednisolone 3-5 mg daily (once or twice daily) may be used for patients with compliance issues 1
• Avoid dexamethasone due to difficulty with dose titration and high risk of Cushingoid side effects 1
• Long-acting synthetic glucocorticoids are associated with more adverse effects including increased infections, cardiovascular morbidity, and metabolic complications 2

Mineralocorticoid Replacement

All patients with confirmed aldosterone deficiency require fludrocortisone 1:

• Starting dose: 50-100 mcg daily in adults 1
• Dose range: May require 50-200 mcg daily based on clinical response 2
• Salt intake: Patients should NOT restrict dietary salt 1

Important Consideration

Hydrocortisone has significant mineralocorticoid activity, prednisolone has reduced activity, and dexamethasone has none 2. This affects fludrocortisone dosing requirements.

Monitoring Strategy

Clinical Assessment (Primary)

Monitor replacement using clinical parameters only—not hormone levels 1:

• Body weight
• Postural blood pressure
• Energy levels
• Signs of glucocorticoid excess (Cushingoid features)
• Salt craving (indicates under-replacement)
• Edema (indicates over-replacement)
• Blood electrolytes (sodium, potassium) 1

Do not use hormonal monitoring (cortisol or ACTH levels) to adjust glucocorticoid doses 1. These values are unreliable for dose titration in replacement therapy.

Special Populations

Pediatric Dosing

• Hydrocortisone: 8 mg/m² body surface area daily, divided into 3-4 doses 1, 2

Pregnancy

• Use hydrocortisone (not cortisone acetate, prednisolone, or dexamethasone) 1
• Never use dexamethasone—it crosses the placenta 1
• Increase dose during third trimester based on clinical symptoms 1
• Use stress dosing during active labor (equivalent to major surgery) 1

Critical Pitfalls to Avoid

1. Over-replacement: Excess glucocorticoids cause increased mortality, infections, cardiovascular disease, metabolic complications, and impaired quality of life 2

2. Using long-acting glucocorticoids as first-line: These disrupt normal circadian rhythm and increase adverse effects 2

3. Monitoring with hormone levels: Serum cortisol and ACTH are not useful for dose adjustment 1

4. Inadequate stress dosing: Patients require education about increasing doses during illness, stress, or surgery

5. Salt restriction: Patients on fludrocortisone should maintain normal salt intake 1

Adjunctive Therapy

DHEA replacement (25-50 mg daily) may be considered in women with persistent low libido, depression, or low energy despite optimized glucocorticoid and mineralocorticoid replacement 1:

• Trial for 6 months
• Discontinue if no sustained benefit
• Monitor morning DHEA-sulfate levels (target mid-normal range) 1

The evidence for DHEA remains inconsistent, so it should only be used in selected symptomatic patients after optimizing conventional replacement 1, 3.