Class: Potassium-sparing diuretic
- Tablets 25 mg
- Tablets 50 mg
- Tablets 100 mg
- Tablets 25 mg
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%.
Spironolactone is greater 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.
Indications and Usage
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; management of essential hypertension; treatment of hypokalemia.
Treatment of hirsutism; relief of PMS symptoms; short-term treatment of familial male precocious puberty; and short-term treatment of acne vulgaris.
Anuria; acute renal insufficiency; impaired renal excretory function; hyperkalemia.
Dosage and AdministrationDiagnosis of Primary Hyperaldosteronism
PO 400 mg/day for 4 days (short test) or 3 to 4 wk (long test).Maintenance Therapy for Hyperaldosteronism
PO 100 to 400 mg daily in single or divided doses.Edema
PO 25 to 200 mg/day in single or divided doses.Children
PO 3.3 mg/kg/day in single or divided doses.Essential Hypertension
PO 50 to 100 mg/day in single or divided doses.Children
PO 1 to 2 mg/kg twice daily.Diuretic-Induced Hypokalemia
PO 25 to 100 mg/day when oral potassium or other potassium-sparing regimens are inappropriate.
Suspension is stable for 30 days under refrigeration. Protect from light. Store tablets at room temperature.
Drug InteractionsACE inhibitors
May result in severely elevated serum potassium levels.Digitalis glycosides
May decrease digoxin clearance, resulting in increased serum digoxin levels and toxicity; may attenuate inotropic action of digoxin.Mitotane
May decrease therapeutic response to mitotane.Potassium preparations
May severely increase serum potassium levels, possibly resulting in cardiac arrhythmias or cardiac arrest. Do not take with potassium preparations.Salicylates
May result in decreased diuretic effect.
Laboratory Test Interactions
Drug may cause falsely elevated serum digoxin values with radioimmunoassay (assay specific) for measuring digoxin.
Drowsiness; lethargy; headache; mental confusion; ataxia.
Maculopapular or erythematous cutaneous eruptions; urticaria.
Cramping; diarrhea; gastric bleeding; gastric ulceration; gastritis; vomiting.
Inability to achieve or maintain erection.
Hyperchloremic metabolic acidosis in decompensated hepatic cirrhosis.
Gynecomastia; irregular menses or amenorrhea; postmenopausal bleeding; hirsutism; deepening of voice; drug fever; carcinoma of breast.
Category D .
Excreted in breast milk.
Electrolyte imbalances and BUN increase
Hyperkalemia (serum potassium greater than 5.5 mEq/L), hyponatremia, hypochloremia and increases in BUN may occur.
- Explain that medication's full diuretic effect may not be achieved for 1 to 2 wk.
- Instruct patient to avoid large quantities of potassium-rich foods or potassium salt substitutes.
- For patient being treated for hypertension, explain that patient may feel tired for several weeks because body needs to adjust to lowered BP.
- Instruct patient to take drug with food to minimize GI irritation.
- Tell patient to weigh self twice weekly and to notify health care provider of any increase.
- Instruct patient to notify health care provider if new symptoms develop.
- Tell patient to report these symptoms to health care provider: GI cramping, diarrhea, lethargy, thirst, headache, skin rash, menstrual abnormalities, deepening of voice, and breast enlargement in men.
- Advise patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness.
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