Fludrocortisone: salt and fluid balance replacement

The adrenal glands make two broad groups of steroid hormones. Glucocorticoids, such as cortisol, are replaced by tablets like hydrocortisone. Mineralocorticoids, mainly aldosterone, regulate sodium, potassium and fluid, and fludrocortisone fills this role. The emc information describes it as mineralocorticoid replacement therapy for primary adrenocortical insufficiency (Addison disease) and for salt-losing adrenogenital syndrome. The two replacement medicines are often used together.

A dedicated NHS patient page was not available when checked, so this guide relies on the emc summary.

Fludrocortisone is taken by mouth once a day or divided, in a dose set by an endocrinologist and adjusted using blood pressure and blood results. The SmPC states a daily adult range and a smaller range for children based on age and weight. The tablet is scored only to make breaking easier for swallowing, not to divide into equal doses, so ask your pharmacist if you need part of a tablet. Storage conditions vary by product, some needing cold storage, so read the packaging.

Because it holds on to sodium strongly, blood pressure, serum electrolytes and fluid status need careful oversight. The SmPC says periodic checking of electrolytes is advisable during prolonged therapy. Blood tests often include sodium, potassium and sometimes renin. Tell your clinic about swollen ankles, headaches, rapid weight gain, muscle weakness or cramps.

The SmPC lists hypertension, oedema, enlarged heart, congestive heart failure, potassium loss and hypokalaemic alkalosis as frequent effects of too much mineralocorticoid effect. Psychiatric effects, including mood changes, are possible. Symptoms of low potassium include muscle pain, weakness, cramps and noticeable palpitations; swelling and breathlessness may signal fluid overload. Report these promptly.

• Urgent advice: breathlessness, rapid swelling, chest pain.

• Prompt advice: persistent headache, muscle cramps, weakness or palpitations.

The SmPC advises avoiding fludrocortisone in systemic infections unless antimicrobial treatment is given, and says live vaccines are contraindicated. After prolonged use, doses must be reduced gradually to prevent acute adrenal insufficiency. People with Addison disease also need extra glucocorticoid during illness, surgery or injury; follow the sick-day plan you have been given and carry your steroid emergency card.

Adrenal replacement is long term, so small routines help: take tablets at the same times daily, keep a spare supply when travelling, carry your steroid emergency card, and keep appointments for blood pressure and electrolyte checks. Because psychiatric effects such as mood change are listed in the SmPC, tell your clinic if you feel unusually low, agitated or confused. If you are given advice about salt intake, follow your endocrinologist rather than general online guidance. Wear or carry medical identification that states you have adrenal insufficiency, and make sure family or colleagues know where your emergency card and any emergency medication are kept.

Fludrocortisone is used in people who need replacement, so stopping is not an option; discuss pregnancy plans and breastfeeding with your endocrinology team so doses can be monitored. Dizziness from low blood pressure, or high blood pressure symptoms, can affect concentration, so avoid driving if you feel unwell.

Fludrocortisone is prescription only. The emc lists tablets and an oral solution from several manufacturers. Suspected side effects can be reported through the Yellow Card scheme.