indication

For partial replacement therapy for primary and secondary adrenocortical insufficiency in Addison's disease and for the treatment of salt-losing adrenogenital syndrome.

pharmacology

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.

mechanism of action

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.

toxicity

Effects of overexposure include irritation, cardiac edema, increased blood volume, hypertension, cardiac arrhythmias, enlargement of the heart, headaches, and weakness of the extremities.

biotransformation

Hepatic, some renal.

half life

3.5 hours

drug interactions

Acenocoumarol: The corticosteroid, fludrocortisone, alters the anticoagulant effect, acenocoumarol.

Acetylsalicylic acid: The corticosteroid, fludrocortisone, may decrease the effect of the salicylate, acetylsalicylic acid.

Ambenonium: The corticosteroid, fludrocortisone, may decrease the effect of the anticholinesterase, ambenonium.

Amobarbital: The barbiturate, amobarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Anisindione: The corticosteroid, fludrocortisone, alters the anticoagulant effect of anisindione.

Aprobarbital: The barbiturate, aprobarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Bismuth Subsalicylate: The corticosteroid, fludrocortisone, may decrease the effect of the salicylate, bismuth subsalicylate.

Butabarbital: The barbiturate, butabarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Butalbital: The barbiturate, butalbital, may decrease the effect of the corticosteroid, fludrocortisone.

Butethal: The barbiturate, butethal, may decrease the effect of the corticosteroid, fludrocortisone.

Dicumarol: The corticosteroid, fludrocortisone, alters the anticoagulant effect of dicumarol.

Dihydroquinidine barbiturate: The barbiturate, dihydroquinidine barbiturate, may decrease the effect of the corticosteroid, fludrocortisone.

Edrophonium: The corticosteroid, fludrocortisone, may decrease the effect of the anticholinesterase, edrophonium.

Ethotoin: The enzyme inducer, ethotoin, may decrease the effect of the corticosteroid, fludrocortisone.

Fosphenytoin: The enzyme inducer, fosphenytoin, may decrease the effect of the corticosteroid, fludrocortisone.

Heptabarbital: The barbiturate, heptabarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Hexobarbital: The barbiturate, hexobarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Magnesium salicylate: The corticosteroid, fludrocortisone, may decrease the effect of magnesium salicylate.

Mephenytoin: The enzyme inducer, mephenytoin, may decrease the effect of the corticosteroid, fludrocortisone.

Methohexital: The barbiturate, methohexital, may decrease the effect of the corticosteroid, fludrocortisone.

Methylphenobarbital: The barbiturate, methylphenobarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Midodrine: Increased arterial pressure

Neostigmine: The corticosteroid, fludrocortisone, may decrease the effect of the anticholinesterase, neostigmine.

Pentobarbital: The barbiturate, pentobarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Phenobarbital: The barbiturate, phenobarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Phenytoin: The enzyme inducer, phenytoin, may decrease the effect of the corticosteroid, fludrocortisone.

Primidone: The barbiturate, primidone, may decrease the effect of the corticosteroid, fludrocortisone.

Pyridostigmine: The corticosteroid, fludrocortisone, may decrease the effect of the anticholinesterase, pyridostigmine.

Quinidine barbiturate: The barbiturate, quinidine barbiturate, may decrease the effect of the corticosteroid, fludrocortisone.

Rifampin: The enzyme inducer, rifampin, may decrease the effect of the corticosteroid, fludrocortisone.

Salicylate-sodium: The corticosteroid, fludrocortisone, may decrease the effect of the salicylate, salicylate-sodium.

Salsalate: The corticosteroid, fludrocortisone, may decrease the effect of the salicylate, salsalate.

Secobarbital: The barbiturate, secobarbital, may decrease the effect of the corticosteroid, fludrocortisone.

Tacrine: Tacrine and Fludrocortisone may independently exacerbate muscle weakness in myasthenia gravis patients. Monitor for additive muscle weakness effects.

Talbutal: The barbiturate, talbutal, may decrease the effect of the corticosteroid, fludrocortisone.

Trastuzumab: Trastuzumab may increase the risk of neutropenia and anemia. Monitor closely for signs and symptoms of adverse events.

Trisalicylate-choline: The corticosteroid, fludrocortisone, may decrease the effect of the salicylate, trisalicylate-choline.

Vecuronium: Vecuronium may increase the adverse neuromuscular effects of systemic corticosteroids, such as Fludrocortisone. Monitor for increased muscle weakness and signs of polyneuropathies and myopathy.

Warfarin: The corticosteroid, fludrocortisone, alters the anticoagulant effect of warfarin.