💊 Fludrocortisone for Hypotension: How It Works, Dose & Side Effects

When lifestyle changes aren’t enough to manage symptomatic low blood pressure, doctors may turn to medications that help the body hold onto salt and water. One of the most effective and widely prescribed is fludrocortisone (brand name Florinef). Dr. Ravi Sishir Reddy explains how this synthetic hormone works, who it’s for, and what you need to know about its safe use.

1. What Is Fludrocortisone?

Fludrocortisone is a synthetic mineralocorticoid — a man‑made version of the hormone aldosterone, which is naturally produced by the adrenal glands. Aldosterone’s main job is to signal the kidneys to reabsorb sodium and water and excrete potassium. By mimicking aldosterone, fludrocortisone increases blood volume, which raises blood pressure.

It is primarily used to treat:

• Orthostatic hypotension (especially when due to autonomic dysfunction).
• Primary adrenal insufficiency (Addison’s disease), in combination with a glucocorticoid like hydrocortisone.
• Salt‑wasting congenital adrenal hyperplasia.

Fludrocortisone is not a first‑line drug for everyone with low BP. It is prescribed when simple measures — increased fluid, salt, and compression stockings — are insufficient and symptoms persist.

2. How Does Fludrocortisone Raise Blood Pressure?

Fludrocortisone binds to mineralocorticoid receptors in the kidneys, causing the distal tubules to retain sodium and water. This expands the plasma volume — literally increasing the amount of fluid in the bloodstream. A larger volume pushes harder against the vessel walls, raising blood pressure.

The effect builds gradually over several days to a week. It also enhances the sensitivity of blood vessels to natural vasoconstrictors (like norepinephrine), which helps counteract the vasodilation that causes orthostatic drops.

3. How Is Fludrocortisone Taken?

• Typical starting dose: 0.1 mg (100 micrograms) once daily, often in the morning.
• Dose adjustment: The dose can be increased gradually (up to 0.2‑0.3 mg daily) based on blood pressure response and tolerance. Some patients require only 0.05 mg every other day.
• Monitoring: Regular checks of blood pressure (lying and standing), body weight, and electrolytes (especially potassium and sodium) are essential. The goal is to reduce symptoms without causing supine hypertension or fluid overload.
• Duration: It is typically a long‑term treatment for chronic conditions like Addison’s or autonomic failure.

Dr. Reddy emphasises that fludrocortisone should be taken exactly as prescribed. Do not stop it abruptly, and always inform any new doctor that you are on it, as it can affect the results of certain tests and interacts with other medications.

4. Side Effects and Potential Risks

Because fludrocortisone expands blood volume and alters electrolytes, it comes with a set of possible side effects:

• Fluid retention: Swelling in the ankles or feet, weight gain.
• Hypokalemia (low potassium): Fludrocortisone increases potassium loss. Muscle cramps, weakness, or palpitations can occur. Potassium levels must be monitored, and a potassium supplement or potassium‑rich diet may be needed.
• Hypertension: Especially supine (lying down) hypertension. This is a common dose‑limiting side effect. Blood pressure should be checked in multiple positions.
• Headache.
• Increased susceptibility to infections: At high doses, fludrocortisone has some glucocorticoid activity and can modestly suppress the immune system, though this is less significant than with prednisone.
• Long‑term use: At very high doses over years, the mineralocorticoid effect can contribute to left ventricular hypertrophy and fibrosis, so the lowest effective dose is always used.

5. Contraindications: Who Should Avoid Fludrocortisone?

• Patients with heart failure — the increased fluid volume can worsen congestion.
• Severe hypertension that is not well controlled.
• Severe kidney disease where sodium and fluid handling is impaired.
• Electrolyte imbalances that cannot be corrected.
• Known allergy to fludrocortisone or any tablet component.

Caution is required in patients with liver disease, migraines (can worsen), or diabetes (may raise blood sugar slightly). Pregnancy and breastfeeding require a careful risk‑benefit discussion.

6. Practical Advice When Taking Fludrocortisone

• Take in the morning: This mimics the body’s natural rhythm and reduces the risk of nighttime supine hypertension.
• Monitor your blood pressure at home: Keep a log of readings sitting and standing, and bring it to every appointment.
• Watch for swelling: Check your ankles and feet. Sudden weight gain may indicate fluid retention.
• Don’t restrict salt unless instructed otherwise: Fludrocortisone works in tandem with adequate dietary sodium. Your doctor will advise on a safe salt intake.
• Tell your doctor about muscle cramps or palpitations: These may signal low potassium.
• Carry a medical alert card if you are on long‑term fludrocortisone, especially if it is part of Addison’s disease management.