DrugindexOnline^{2nd edition}

Pronouncation: (flew-droe-CORE-tih-sone ASS-uh-TATE)
Class: Mineralocorticoid

Trade Names:
Florinef Acetate
- Tablets 0.1 mg

Mechanism of Action

Pharmacology

Exerts salt-retaining (mineralocorticoid) activity by acting on renal distal tubules to enhance reabsorption of sodium and increasing urinary excretion of potassium, hydrogen, and magnesium ions.

Pharmacokinetics

Absorption

Fludrocortisone is rapidly absorbed from the GI tract. T _max is 1.7 h.

Elimination

The plasma t _{1/ 2} is about 3.5 h. The biological t _{1/ 2} is 18 to 36 h.

Indications and Usage

Partial replacement therapy for primary and secondary adrenocortical insufficiency in Addison disease; treatment of salt-losing adrenogenital syndrome.

Unlabeled Uses

Treatment of severe orthostatic hypotension.

Contraindications

Systemic fungal infections.

Dosage and Administration

Addison Disease
Adults

PO 0.05 to 0.1 mg/day (range, 0.1 mg 3 times/wk to 0.2 mg/day).

Salt-Losing Adrenogenital Syndrome
Adults

PO 0.1 to 0.2 mg/day.

Drug Interactions

Amphotericin, potassium-losing diuretics

May increase potassium loss.

Anticholinesterase agents (eg, neostigmine)

May antagonize the effects of anticholinesterase agents in myasthenia gravis.

Anticoagulants (eg, warfarin)

Dose requirement of anticoagulant may be reduced or effect opposed.

Barbiturates, hydantoins (eg, phenytoin), rifampin

Decreased fludrocortisone activity.

Salicylates

Serum levels may be reduced by corticosteroids, decreasing the effectiveness; in addition, the ulcerogenic effects of both agents may be increased.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Edema; hypertension; CHF; heart enlargement.

Dermatologic

Bruising; increased sweating; hives; rash.

Miscellaneous

Hypokalemic alkalosis. May also cause adverse reactions associated with glucocorticoids (eg, dexamethasone).

Precautions

Pregnancy

Category C .

Lactation

Excreted in breast milk.

Children

Safety and efficacy not established.

Addison disease

Patients with Addison disease may exhibit exaggerated adverse reactions; monitor closely for development of edema, significant weight gain, or increases in BP.

Adrenal insufficiency

Adrenal insufficiency may occur. Increased doses may be needed before, during, or after stressful situations.

Electrolyte disturbances

Sodium retention and potassium loss are increased by high sodium intake. Sodium restriction and potassium supplementation may be necessary.

GI

Use with caution in patients with nonspecific ulcerative colitis if there is a possibility of impending perforation, abscess or other pyogenic infection, diverticulitis, fresh intestinal anastomoses, or peptic ulcer.

Infections

Drug may mask signs of infection and may decrease host-defense mechanisms to prevent dissemination of infection.

Immunizations

Because of possible hazards of neurological complications and a lack of antibody response, do not vaccinate patients against smallpox while receiving corticosteroid therapy or undertake other immunization procedures.

Ocular effects

Prolonged use may produce posterior subcapsular cataracts and glaucoma with possible damage to the optic nerves and may enhance the establishment of secondary ocular infections caused by fungi or viruses.

Supplemental measures

Patients receiving fludrocortisone may need supplemental measures (eg, glucocorticoids, electrolyte control) for optimal control of symptoms.

Overdosage

Symptoms

Hypertension, edema, hypokalemia, excessive weight gain, increase in heart size.

Patient Information

• Instruct patient to take medication exactly as prescribed. If dose is missed, it should be taken as soon as possible. Do not double up if within several hours of next dose. Caution patient not to stop medication abruptly. Instruct patient to notify health care provider if greater than 1 dose is missed or a dosage cannot be taken because of nausea or vomiting.
• Advise patient to reduce dietary sodium, which accelerates potassium loss, and to eat foods rich in potassium.
• Tell patient to notify health care provider when experiencing a stressful situation (eg, emotional upheavals, dental extractions, trauma, surgery, illness) as increased dosage may be needed.
• Instruct patient to report the following symptoms to health care provider: increased or irregular heart beat, high BP, fluid retention, joint pain, muscle weakness, headache, dizziness, fever, unusual weight gain.
• Instruct patient to report euphoria, depression, or other changes in mental status.
• Tell patient to be alert for spontaneous fractures and impaired wound healing.