What is the recommended fludrocortisone dosing schedule for treating postural (orthostatic) hypotension?

Fludrocortisone Dosing for Postural Hypotension

For postural (orthostatic) hypotension, start fludrocortisone at 0.05-0.1 mg once daily in the morning, with titration up to 0.1-0.3 mg daily based on clinical response, monitoring for supine hypertension as the primary dose-limiting side effect.

Initial Dosing Strategy

The FDA-approved starting dose is 0.1 mg daily, though clinical practice often begins at 0.05 mg to minimize side effects 1. According to the 2017 ACC/AHA/HRS syncope guidelines, fludrocortisone increases plasma volume and improves orthostatic symptoms, but supine hypertension is a major limiting factor 2. The 2011 cardiovascular autonomic neuropathy guidelines recommend an initial dose of 0.05-0.1 mg daily with individual titration to 0.1-0.3 mg daily 3.

Dosing Algorithm:

• Start: 0.05-0.1 mg once daily in the morning
• Titrate: Increase by 0.05 mg increments every 1-2 weeks based on response
• Maximum: 0.3 mg daily (doses >0.3 mg risk adrenal suppression and immunosuppression) 2
• Timing: Morning administration mimics aldosterone's circadian rhythm 4

Monitoring and Dose Adjustment

Monitor clinically rather than biochemically 4. Assess for:

• Inadequate dosing: Salt craving, light-headedness, persistent postural BP drop
• Overdosing: Supine hypertension, peripheral edema, weight gain, hypokalemia 4, 1

Measure sitting and standing blood pressure at each visit. Plasma renin activity in the upper reference range indicates appropriate dosing 4, though this is not routinely necessary for dose adjustment.

Critical Caveats

When to Reduce or Avoid:

• Supine hypertension develops: Reduce to 0.05 mg daily or discontinue 2, 1
• Pre-existing hypertension, heart failure, or renal disease: Use extreme caution or consider alternative agents first 2
• Low serum albumin: Risk of severe edema; use cautiously 5

Important Drug Interactions:

• Concurrent glucocorticoids: Patients on prednisolone require MORE fludrocortisone than those on hydrocortisone due to less mineralocorticoid activity 4
• Licorice and grapefruit juice: Potentiate mineralocorticoid effects—must be avoided 4
• Phenytoin: Increases fludrocortisone metabolism, requiring higher doses 4

Evidence Quality and Limitations

The evidence for fludrocortisone in orthostatic hypotension is surprisingly weak. A 2021 Cochrane review found only very low-certainty evidence from three small, short-term RCTs (total 28 participants) 6. Despite this, fludrocortisone remains widely used as first- or second-line therapy based on physiologic rationale and decades of clinical experience 2, 3, 7.

The 2017 ACC/AHA/HRS guidelines give fludrocortisone a Class IIa recommendation (Level B-R) for neurogenic orthostatic hypotension and Class IIb (Level B-R) for vasovagal syncope 2, 8. The 2011 diabetes autonomic neuropathy guidelines provide a Level B recommendation for symptomatic orthostatic hypotension 3.

Comparative Effectiveness:

• Midodrine has stronger evidence (Class IIa, Level B-R) and may be preferred as first-line pharmacotherapy 2, 8
• Droxidopa also has Class IIa evidence for neurogenic orthostatic hypotension 2
• Fludrocortisone is often used when midodrine fails or in combination therapy 3, 9

Practical Implementation

Non-pharmacologic measures must be optimized first 2, 3:

• Increase salt intake (6-9 g/day or 1-2 teaspoons) 2
• Increase fluid intake (2-2.5 L/day)
• Compression garments (thigh-high or abdominal) 2
• Physical counter-pressure maneuvers 2
• Discontinue offending medications 7

Only add fludrocortisone after non-pharmacologic measures prove inadequate 3, 7. The 2019 ACC/AHA/HRS comparison notes fludrocortisone "might be reasonable for patients with recurrent VVS and inadequate response to salt and fluid intake, unless contraindicated" 7.

Special Populations:

• Primary adrenal insufficiency: Standard dose is 0.05-0.2 mg daily for adults 4
• Children: Require higher doses than adults due to lower mineralocorticoid sensitivity 4
• Pregnancy: Can be continued if needed, but monitor closely 4

When Fludrocortisone Fails

If blood pressure remains uncontrolled despite fludrocortisone:

1. Add midodrine (5-10 mg three times daily) 2, 9
2. Consider pyridostigmine (30-60 mg three times daily) for refractory cases 2, 9
3. For postprandial hypotension: octreotide (25-50 mcg subcutaneously) 2
4. Emerging option: low-dose atomoxetine (10-18 mg daily) for central autonomic failure 9

Do not use diuretics or aldosterone antagonists (spironolactone, eplerenone) in patients on fludrocortisone—they are contraindicated 4.