Trade Names:Aldactone- Tablets 25 mg- Tablets 50 mg- Tablets 100 mgNovo-Spiroton (Canada)
Competitively inhibits aldosterone in distal tubules, resulting in increased excretion of sodium and water and decreased excretion of potassium.
Spironolactone is rapidly and extensively metabolized. Food increases bioavailability by almost 100%. Following a 100 mg dose, mean C max is 80 ng/mL; T max is 2.6 h.
Spironolactone is more than 90% bound to plasma proteins.
Sulfur-containing products are predominant metabolites and are thought to be primarily responsible together with spironolactone for the therapeutic effect of the drug.
Metabolites are excreted primarily in the urine and secondarily in bile. Half-life is approximately 1.4 h.
Short-term preoperative treatment of primary hyperaldosteronism; long-term maintenance therapy for idiopathic hyperaldosteronism; management of edematous conditions in CHF, cirrhosis of liver, and nephrotic syndrome; essential hypertension; treatment of hypokalemia; long-term maintenance therapy for patients with discrete aldosterone-producing adrenal adenomas; increase survival and reduce need for hospitalization for severe heart failure (New York Heart Association [NYHA] class III to IV).
Treatment of hirsutism in women.
Acute renal insufficiency; anuria; hyperkalemia; impaired renal excretory function.
PO 400 mg/day for 4 days (short test) or 3 to 4 wk (long test).Maintenance Therapy for HyperaldosteronismAdults
PO 100 to 400 mg daily in single or divided doses.Edema (CHF, hepatic cirrhosis, or nephrotic syndrome)Adults
PO 25 to 200 mg/day in single or divided doses.Essential HypertensionAdults
PO 50 to 100 mg/day in single or divided doses.Diuretic-Induced HypokalemiaAdults
PO 25 to 100 mg/day when oral potassium or other potassium-sparing regimens are inappropriate.Severe Heart Failure (NYHA class III to IV)Adults
PO Start with 25 mg once daily if serum potassium is 5 mEq/L or less and serum creatinine is 2.5 mg/dL or less. Dosage may be increased to 50 mg once daily if indicated in patients who tolerate 25 mg/day. Patients who do not tolerate 25 mg/day may have their dosage decreased to 25 mg every other day.
Store tablets below 77°F.
May result in severely elevated serum potassium levels.Alcohol, barbiturates, narcotics
Orthostatic hypotension may be potentiated.Angiotensin II receptor antagonists (eg, candesartan, losartan, telmisartan)
Risk of hyperkalemia, especially in patients with renal impairment or type 2 diabetes, may be increased.Corticosteroids
Increased risk of electrolyte depletion, particularly hypokalemia.Digitalis glycosides
May decrease digoxin clearance, resulting in increased serum digoxin levels and toxicity; may attenuate inotropic action of digoxin.Diuretics
Risk of dilutional hyponatremia may be increased.Mitotane
May decrease therapeutic response to mitotane.Salicylates
May result in decreased diuretic effect.Lithium
Lithium clearance may be reduced, increasing the risk of toxicity.Nondepolarizing muscle relaxants (eg, tubocurarine)
Increased responsiveness to muscle relaxant effect may occur.NSAIDs (eg, indomethacin)
Risk of severe hyperkalemia may be increased.Potassium preparations
May severely increase serum potassium levels, possibly resulting in cardiac arrhythmias or cardiac arrest. Do not take with potassium preparations.Pressor amines (eg, norepinephrine)
Vascular responsiveness to norepinephrine may be decreased. Use with caution in patients receiving regional or general anesthesia.
Drug may cause falsely elevated serum digoxin values with radioimmunoassay (assay specific) for measuring digoxin.
Ataxia; drowsiness; headache; lethargy; mental confusion.
Erythematous or maculopapular cutaneous eruptions; urticaria.
Cramping; diarrhea; gastritis; GI bleeding; nausea; ulceration; vomiting.
Amenorrhea; breast carcinoma; gynecomastia; inability to achieve or maintain an erection; irregular menses; postmenopausal bleeding.
Mixed cholestatic/hepatocellular toxicity.
Renal dysfunction including renal failure
Spironolactone has been shown to be tumorogenic in chronic toxicity studies in rats. The drug should only be used for conditions included under indications and usage. Unnecessary use of the drug should be avoided. Monitor for evidence of fluid or electrolyte imbalance (eg, alkalosis, hyperkalemia, hypomagnesemia, hyponatremia). Monitoring serum and urine electrolytes are especially important when the patient is vomiting excessively or receiving parenteral fluids. Obtain ECG if hyperkalemia is suspected.
Periodically measure serum electrolytes to detect possible electrolyte imbalance, particularly in the elderly and in patients with renal or hepatic impairment. It is critical to monitor serum potassium in patients with severe heart failure; monitor potassium and creatine 1 wk after starting therapy, monthly for the first 3 mo, then quarterly for a year, and then every 6 mo.
Category D .
Excreted in breast milk.
Safety and efficacy not established.
Contraindicated in patients with anuria, acute renal insufficiency, and/or significant impairment of renal excretory function. Transient elevation of BUN may occur, particularly in patients with preexisting renal impairment.
Use with caution because minor alterations in fluid and electrolyte balance may precipitate hepatic coma.
Reversible hyperchloremic metabolic acidosis, usually in association with hyperkalemia, has been reported in patients with decompensated hepatic cirrhosis.
Hyperkalemia (serum potassium more than 5.5 mEq/L), hyponatremia, hypochloremia, and increases in BUN may occur.
Gynecomastia, related to both dose and duration of treatment, may occur.
Hyperkalemia may be fatal. Discontinue or interrupt treatment for serum potassium more than 5 mEq/L or serum creatine more than 4 mg/dL.
Diarrhea, dizziness, drowsiness, mental confusion, maculopapular or erythematous rash, nausea, vomiting.In patients with severe liver disease
Hepatic coma, hyperkalemia, hyponatremia.In patients with renal function impairment
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