Fludrocortisone is a synthetic adrenocortical steroid possessing very potent mineralocorticoid properties and high glucocorticoid activity. It is indicated as partial replacement therapy for primary and secondary adrenocortical insufficiency in Addison’s disease and for the treatment of salt-losing adrenogenital syndrome. The physiologic action of fludrocortisone acetate is similar to that of hydrocortisone. However, the effects of fludrocortisone acetate, particularly on electrolyte balance, but also on carbohydrate metabolism, are considerably heightened and prolonged. Mineralocorticoids act on the distal tubules of the kidney to enhance the reabsorption of sodium ions from the tubular fluid into the plasma; they increase the urinary excretion of both potassium and hydrogen ions.

Pharmacology

Fludrocortisone binds the mineralocorticoid receptor (aldosterone receptor). This binding (or activation of the mineralocorticoid receptor by fludrocortisone) in turn causes an increase in ion and water transport and thus raises extracellular fluid volume and blood pressure and lowers potassium levels.

Used for oral mineralocorticoid replacement therapy in:

• Primary and secondary adrenocortical insufficiency in Addison’s disease
• Salt losing adrenogenital syndrome
• Postural hypotension

Primary and secondary Adrenocortical Insufficiency in Addison’s disease: Usual dose may range from 0.2 mg 3 times weekly to 0.2 mg daily. If hypertension occurs, reduce dosage to 0.05 mg daily. Administer concomitantly with Cortisone or hydrocortisone.

Salt-Losing Adrenogenital Syndrome: 0.1 to 0.2 mg/day.

Postural Hypotension: 0.1-0.4 mg daily to diabetic patients with postural hypotension; 0.05-0.2 mg daily to patients with postural hypotension secondary to Levodopa therapy.

In case of adrenal insufficiency, no absolute contraindications are applicable. In the treatment of non-endocrine diseases where pharmacological dose are more likely to be used, the contraindications to be considered carefully. Relative contraindications include: systemic fungal infection, hypersensitivity to Fludrocortisone, diabetic mellitus, osteoporosis and acute infection.

Most adverse reactions are caused by the drug’s mineralocorticoid activity (retention of sodium andwater) include erythema, purpura, vertigo, pancreatitis, increased intraocular pressure, muscular weakness, hypertension, edema, cardiac enlargement, congestive heart failure, steroid myopathy, peptic ulcer, osteoporosis, convulsions, menstrual irregularities, potassium loss, hypokalemic alkalosis, allergic and anaphylactic reaction etc. When Fludrocortisones is used in the small dosages recommended, side effects are not usually a problem; however the above mentioned unwanted effects should be kept in mind, particularly when Fludrocortisones is used over a prolonged period of time or in conjunction with cortisone or a similar glucocorticoid.

Overdose Effects

Overdose is unlikely; however, treatment of overdose is by supportive and symptomatic therapy.

Because of its marked effect on sodium retention, the use of Fludrocortisone in the treatment of conditions other than those indicated herein is not advised. Fludrocortisone should be used with caution in patients suffering from different infections (like tuberculosis, measles, chicken pox, herpes zoster or threadworm infestation), congestive cardiac failure, hypertension, renal insufficiency, osteoporosis, drug-induced secondary adrenocortical insufficiency, peptic ulcer, intestinal anastomosis and ulcerative colitis.

Pregnancy & Lactation

Pregnancy category C. There are no adequate and well-controlled studies in pregnant women. Fludrocortisone is only recommended for use during pregnancy when there are no alternatives and benefit outweighs risk.

Lactation: There are no data on the excretion of fludrocortisone into human milk. However, corticosteroids (systemic therapy) are distributed into breast milk and could cause growth suppression and/or other adverse effects in nursing infants. The manufacturer recommends that caution be used when administering Fludrocortisone to nursing women.