Mineralocorticoid Pregnancy: It may be decided to continue a pregnancy in a woman requiring replacement mineralocorticoid therapy despite the risk to the foetus; where corticosteroids are essential, patients with normal pregnancies may be treated as though non-gravid. There is evidence of harmful effects in animals and there may be a small risk of cleft palate and intra-uterine growth retardation; hypoadrenalism may occur in the neonate. Patients with pre-eclampsia or fluid retention require close monitoring. Corticosteroids are found in breast milk — infants of mothers given substantial doses should be observed for signs of hypoadrenalism. (US labelling classifies fludrocortisone acetate as pregnancy Category C.)

Fludrocortisone acetate

Brand names: Florinef

Used in: Syncope

A synthetic corticosteroid with potent mineralocorticoid activity, used mainly for mineralocorticoid replacement in adrenal insufficiency (such as Addison's disease and salt-losing congenital adrenal hyperplasia) and for orthostatic hypotension.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 0.05 mg to 0.3 mg daily

Route: Oral (tablets)

Frequency: Once daily (stated as a daily dosage range)

Supplementary parenteral administration of sodium-retaining hormones is not necessary. When an enhanced glucocorticoid effect is desirable, cortisone or hydrocortisone by mouth should be given concomitantly with fludrocortisone acetate. Elderly: no specific dosage recommendations, but see §4.4. Because fludrocortisone is a potent mineralocorticoid, both the dosage and salt intake should be carefully monitored to avoid hypertension, oedema or weight gain; periodic checking of serum electrolytes is advisable during prolonged therapy. Undesirable effects may be minimised by using the lowest effective dose for the minimum period, with frequent review to titrate the dose against disease activity. Adrenal cortical atrophy develops during prolonged therapy and may persist for years after stopping — withdrawal after prolonged therapy must always be gradual, tapered over weeks or months. Patients on long-term therapy may require supportive corticosteroid therapy in times of stress (trauma, surgery, severe illness) during treatment and for up to a year afterwards. Patients should carry a steroid treatment card. PAEDIATRIC (UK SPC): one tablet (0.05 mg) to two tablets (0.1 mg) daily — no per-kg dose is stated, so paedDose is left null; caution in the event of exposure to chickenpox, measles or other communicable diseases; verify against a children's formulary. US labelling (cross-check only, not the primary source): Addison's disease — usual dose 0.1 mg daily, with dosage ranging from 0.1 mg three times a week to 0.2 mg daily, reduced to 0.05 mg daily if transient hypertension develops, preferably given with cortisone 10 mg to 37.5 mg daily or hydrocortisone 10 mg to 30 mg daily in divided doses; salt-losing adrenogenital syndrome — 0.1 mg to 0.2 mg daily; safety and effectiveness in children have not been established (US label). The interaction list below is taken from the US labelling's Drug Interactions section, as the UK SPC §4.5 was not captured in this fetch. Source: eMC SPC for Fludrocortisone acetate 0.05 mg tablets (§4.2).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Systemic infections, unless specific anti-infective therapy is employed
Systemic fungal infections (US labelling)
Use in conditions other than those indicated is not advised, because of the marked effect on sodium retention

Side effects

Hypokalaemia (very common); hypokalaemic alkalosis and decreased appetite (uncommon)
Hypertension (very common) and congestive cardiac failure (very common); cardiomegaly (uncommon)
Oedema and swelling (common); sodium and fluid retention
Headache (common); muscular weakness (common); muscle atrophy (uncommon)
Seizure, epilepsy, syncope, loss of consciousness, dysgeusia, delusional perception, illusion, hallucination, diarrhoea (uncommon); on withdrawal — fever, myalgia, arthralgia, rhinitis, conjunctivitis, painful itchy skin nodules and weight loss, and too-rapid dose reduction can lead to acute adrenal insufficiency, hypotension and death

Interactions

Amphotericin B or potassium-depleting diuretics (benzothiadiazines and related drugs, ethacrynic acid, furosemide) — enhanced hypokalaemia; check serum potassium frequently and use potassium supplements if necessary
Digitalis glycosides — enhanced possibility of arrhythmias or digitalis toxicity associated with hypokalaemia; monitor serum potassium
Oral anticoagulants — decreased prothrombin time response; monitor prothrombin levels and adjust anticoagulant dosage
Antidiabetic drugs (oral agents and insulin) — diminished antidiabetic effect; monitor for hyperglycaemia and adjust dosage upward if necessary
Aspirin — increased ulcerogenic effect and decreased pharmacologic effect of aspirin; salicylate toxicity may rarely occur when steroids are discontinued after concurrent high-dose aspirin
Barbiturates, phenytoin or rifampicin — increased metabolic clearance of fludrocortisone acetate through hepatic enzyme induction
Live vaccines should not be administered; antibody response to vaccines is reduced during corticosteroid therapy (§4.4)

Clinical monograph

How it works

Fludrocortisone activates renal mineralocorticoid receptors to promote sodium and water retention and potassium excretion, restoring electrolyte and volume balance.

Prescribing in practice

The most important safety point is mineralocorticoid excess causing sodium and fluid retention, hypertension, oedema, and hypokalaemia, which require monitoring and dose adjustment.
It is used alongside glucocorticoid replacement in adrenal insufficiency and does not replace the need for stress-dose glucocorticoid cover during illness.
Effects may be potentiated or opposed by drugs affecting potassium or fluid balance, including diuretics and NSAIDs.

Monitoring

Monitor blood pressure, serum electrolytes (especially sodium and potassium), and signs of fluid overload, adjusting dose accordingly.

Counselling the patient

Do not stop this medicine suddenly and carry steroid emergency information at all times.
Report ankle swelling, breathlessness, or significant weight gain.
Continue your separate glucocorticoid and follow sick-day rules during illness.

Evidence & guidelines

Fludrocortisone is the standard mineralocorticoid replacement in primary adrenal insufficiency as set out in endocrine society guidance.

Reference: Endocrine Society guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Drugs

Pathways