Fludrocortisone Should Not Be Given Every Other Day
Fludrocortisone must be administered daily as a single morning dose, not every other day, because mineralocorticoids are vital for maintaining blood pressure and electrolyte homeostasis, and the medication's pharmacokinetics do not support alternate-day dosing. 1
Standard Dosing Regimen
The tablets are taken in one dose upon awakening each day, typically ranging from 50-200 µg daily for most patients with primary adrenal insufficiency 1
The FDA-approved dosing for Addison's disease is 0.1 mg (100 µg) daily, with a range of 0.1 mg three times weekly to 0.2 mg daily in some cases, but this refers to dose adjustment within a daily regimen, not true alternate-day dosing 2
For congenital adrenal hyperplasia specifically, the recommended dosage is 0.1-0.2 mg daily 2
Why Daily Dosing Is Essential
Mineralocorticoid replacement is critical for blood pressure regulation and preventing life-threatening adrenal crises - under-replacement is common and predisposes patients to recurrent adrenal crises 1
The medication works continuously to maintain sodium retention and potassium excretion; skipping days would create dangerous fluctuations in electrolyte balance 1
Abrupt discontinuation or irregular dosing can trigger adrenal crisis characterized by hypotension, hyponatremia, hyperkalemia, and potentially life-threatening cardiovascular collapse 3
Monitoring Parameters for Optimal Daily Dosing
Assess blood pressure in both supine and standing positions to detect orthostatic hypotension (suggesting under-replacement) or hypertension (suggesting over-replacement) 1
Monitor for clinical symptoms: salt cravings and lightheadedness indicate under-replacement, while peripheral edema suggests over-replacement 1
Check serum electrolytes regularly - low sodium or high potassium warrant dose increases, while hypertension may require dose reduction (but never complete discontinuation) 1, 3
Special Considerations in CAH Patients
Children and younger adults with CAH often require higher doses (up to 500 µg daily) due to physiological mineralocorticoid resistance in infancy 1
Research shows that 74.1% of pediatric CAH patients receive fludrocortisone with a median daily dose of 88.8 µg, administered daily 4
Infants with CAH have changing mineralocorticoid sensitivity - studies demonstrate that up to 57.6% develop transient hypertension at 18 months when fludrocortisone doses are too high, emphasizing the need for careful daily dose titration rather than alternate-day dosing 5
Critical Pitfalls to Avoid
Never stop fludrocortisone completely when hypertension develops - instead, reduce the daily dose 1
Do not attempt alternate-day dosing to manage side effects - this creates dangerous gaps in mineralocorticoid coverage and increases adrenal crisis risk 3
Patients should be advised to consume salt and salty foods without restriction, and avoid potassium-containing salt substitutes, to support the daily fludrocortisone regimen 1
Avoid medications that interact with fludrocortisone (diuretics, acetazolamide, NSAIDs, liquorice, grapefruit juice) as these can unpredictably alter mineralocorticoid effects 1