Fludrocortisone Dosing in Addison's Disease
The recommended starting dose of fludrocortisone for patients with Addison's disease is 0.05-0.1 mg once daily in the morning. 1, 2
Initial Dosing Recommendations
- The FDA-approved starting dose for fludrocortisone in Addison's disease is 0.1 mg daily, although dosage ranging from 0.1 mg three times a week to 0.2 mg daily may be employed based on individual response 1
- Most patients with primary adrenal insufficiency should take 50-200 μg (0.05-0.2 mg) fludrocortisone as a single daily dose, preferably in the morning 3, 4
- Fludrocortisone should always be administered in conjunction with glucocorticoid replacement (typically hydrocortisone 15-25 mg daily in divided doses) 1, 3
Dose Adjustment Parameters
Dose adjustments should be based on clinical response and laboratory parameters 2:
- Blood pressure (both supine and standing positions)
- Serum electrolytes (sodium and potassium)
- Clinical symptoms (salt cravings, lightheadedness, peripheral edema)
Increase fludrocortisone dose when 3, 2:
- Orthostatic hypotension is present
- Persistent salt cravings despite adequate sodium intake
- Hyponatremia or hyperkalemia develops
Decrease fludrocortisone dose when 3, 2:
- Essential hypertension develops (reduce dose, but do not stop completely)
- Peripheral edema occurs
- Hypokalemia develops
Special Populations and Considerations
- Children and younger adults may require higher doses of fludrocortisone (up to 500 μg daily) 3, 2
- Pregnant women often need increased fludrocortisone doses during the third trimester due to progesterone's anti-mineralocorticoid effects 3
- In the event transient hypertension develops as a consequence of therapy, the dose should be reduced to 0.05 mg daily 1
Monitoring Recommendations
- Patients with primary adrenal insufficiency should be reviewed at least annually 3
- Assessment should include measurement of weight, blood pressure (both supine and standing), and serum electrolytes 3, 2
- Under-replacement with fludrocortisone is common and may predispose patients to recurrent adrenal crises 2
Medication Interactions and Dietary Considerations
- Patients should be advised to take salt and salty foods ad libitum 3
- Avoid potassium-containing salt substitutes 2
- Avoid liquorice and grapefruit juice as they potentiate the mineralocorticoid effect of hydrocortisone 3, 2
- Medications that may interact with fludrocortisone requiring dose adjustments 3, 2:
- Diuretics
- NSAIDs
- Drospirenone-containing contraceptives (may require higher fludrocortisone doses)
Common Pitfalls to Avoid
- Delaying treatment of suspected acute adrenal insufficiency while waiting for test results 4
- Completely stopping fludrocortisone when hypertension develops (reduce dose instead) 3, 2
- Failing to adjust fludrocortisone during pregnancy or periods of increased physical stress 3
- Abrupt discontinuation of fludrocortisone, which can trigger an adrenal crisis 2
Following these guidelines for fludrocortisone dosing will help optimize mineralocorticoid replacement in patients with Addison's disease, reducing the risk of complications and improving quality of life.