Fluid Intake Recommendations for Patients on Fludrocortisone
Patients taking fludrocortisone should maintain adequate hydration with 2-3 liters of fluid per day and increase salt intake to 6-9 grams daily (1-2 heaping teaspoons), unless contraindicated by hypertension, renal disease, or heart failure. 1
Rationale for Increased Fluid and Salt Intake
- Fludrocortisone is a mineralocorticoid that promotes sodium and water retention while increasing potassium excretion 2
- Patients with adrenal insufficiency on fludrocortisone often experience sodium depletion and may be undertreated with standard doses (0.05-0.1 mg/day) 3
- Adequate fluid and salt intake helps prevent postural hypotension, which is a common symptom of insufficient mineralocorticoid therapy 1
- Patients with vasovagal syncope treated with fludrocortisone particularly benefit from increased fluid intake to maintain adequate blood volume 1
Specific Fluid and Salt Recommendations
- Target 2-3 liters of fluid intake per day 1
- Maintain salt intake of 6-9 grams (100-150 mmol) daily, equivalent to 1-2 heaping teaspoons 1
- Rapid cool water ingestion can be particularly effective in combating orthostatic intolerance 1
- Potassium-containing salt substitutes should be avoided due to the potassium-lowering effects of fludrocortisone 2
Monitoring and Adjustment
- Monitor for signs of adequate mineralocorticoid replacement: 1
- Normal blood pressure without postural hypotension
- Absence of salt craving
- Normal serum sodium and potassium levels
- Normal plasma renin activity
- Watch for signs of excessive fluid retention: 1, 4
- Edema
- Hypertension
- Hypokalemia (serum potassium <3.5 mEq/L)
Special Considerations
- During hot weather or intense physical activity, additional fluid and salt intake may be necessary to replace sweat losses 1
- Patients with primary adrenal insufficiency may require higher fludrocortisone doses (0.2-0.3 mg daily) to maintain adequate sodium balance 3, 5
- Sleeping with the head of the bed elevated (10°) can help maintain more favorable fluid distribution and prevent nocturnal polyuria 1
Precautions
- Monitor serum potassium levels, as fludrocortisone commonly causes hypokalemia requiring supplementation 4, 6
- Avoid licorice and grapefruit juice, which can potentiate the mineralocorticoid effect of hydrocortisone when used concurrently with fludrocortisone 1
- In patients with hypertension, renal disease, or heart failure, fluid and salt intake should be more carefully monitored and may need to be restricted 1
Clinical Indicators for Dose Adjustment
- Persistent postural hypotension suggests inadequate mineralocorticoid effect and may require increased fludrocortisone dose or increased salt/fluid intake 1
- Elevated plasma renin activity indicates suboptimal mineralocorticoid replacement 3, 5
- Weight loss despite adequate glucocorticoid replacement may indicate insufficient mineralocorticoid effect 1
- Development of edema or hypertension suggests excessive mineralocorticoid effect 4, 6