From the Guidelines
It's highly recommended to take fludrocortisone in the morning rather than the afternoon. Fludrocortisone is a synthetic mineralocorticoid that mimics the effects of aldosterone, helping your body retain sodium and excrete potassium. Taking it in the morning aligns with your body's natural cortisol rhythm, which is highest in the early morning and gradually decreases throughout the day. When taken in the afternoon or evening, fludrocortisone may cause sleep disturbances or insomnia because it can increase blood pressure and fluid retention. The dosage of fludrocortisone is related to individual fluid and electrolyte intake/losses, and a daily dose of 50–200 µg is usually sufficient in primary PAI, but a higher dose (up to 500 µg daily) is sometimes needed in children and younger adults or in the last trimester of pregnancy when high levels of progesterone counteract mineralocorticoids 1. Some key points to consider when taking fludrocortisone include:
- Eating sodium salt and salty foods without restriction
- Avoiding potassium-containing salts
- Allowing unrestricted sodium intake and avoiding salt craving as an important component of substitution therapy
- Consulting your healthcare provider if you need to take it in the afternoon due to scheduling conflicts or other medications, as they might suggest adjusting your dosage or timing to minimize potential side effects. Remember that consistency in timing is important for maintaining stable blood pressure and electrolyte levels throughout the day.
From the Research
Administration of Fludrocortisone
- Fludrocortisone is a mineralocorticoid that can be taken in the afternoon, as evidenced by a study where healthy subjects were given 0.5mg fludrocortisone on the second afternoon, resulting in a decrease in mean cortisol and ACTH levels from 16:00 to 24:00 h 2.
- The timing of fludrocortisone administration may not be critical in patients with primary adrenal insufficiency, as plasma renin activity levels were not significantly different at 8 and 32 hours following fludrocortisone administration 3.
Effects of Fludrocortisone
- Fludrocortisone has been shown to inhibit nocturnal hypothalamic-adrenal-pituitary (HPA) axis activity, suggesting a possible role in disorders of HPA axis excess, such as insomnia, depression, and healthy aging 2.
- Fludrocortisone has been used to manage orthostatic hypotension in patients with Parkinson's disease, and ambulatory 24-hour blood pressure recordings have shown that it can increase blood pressure in these patients 4.
- Fludrocortisone has mineralocorticoid activity, causing sodium retention and kaliuresis, and is used to relieve hyperkalemia or ameliorate hyponatremia 5.
Response to Fludrocortisone
- The response of plasma aldosterone to fludrocortisone administration has been studied in patients with primary hyperaldosteronism and other forms of hypertension, and it was found that the test is of little value in the pre-operative differentiation of these conditions 6.
- Patients with primary adrenal insufficiency may require adjustment of their fludrocortisone dose to achieve optimal mineralocorticoid replacement, and monitoring of plasma renin activity levels can be useful in this regard 3.