Spironolactone

A to Z Drug Facts

(SPEER-oh-no-LAK-tone)

Aldactone, Spironolactone,  Novo-Spiroton, Novo-Spirozine

Class: Potassium-sparing diuretic

 Action Competitively inhibits aldosterone in distal tubules, resulting in increased excretion of sodium and water and decreased excretion of potassium.

 Indications 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. Unlabeled use(s): Treatment of hirsutism; relief of PMS symptoms; short-term treatment of familial male precocious puberty; and short-term treatment of acne vulgaris.

 Contraindications Anuria; acute renal insufficiency; impaired renal excretory function; hyperkalemia.

 Route/Dosage

Diagnosis of Primary Hyperaldosteronism

ADULTS: PO 400 mg/day for 4 days (short test) or 3 to 4 wk (long test).

Maintenance Therapy for Hyperaldosteronism

ADULTS: PO 100 to 400 mg daily in single or divided doses.

Edema

ADULTS: 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

ADULTS: PO 50 to 100 mg/day in single or divided doses. CHILDREN: PO 1 to 2 mg/kg bid.

Diuretic-Induced Hypokalemia

ADULTS: PO 25 to 100 mg/day when oral potassium or other potassium-sparing regimens are inappropriate.

 Interactions

ACE 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.

 Lab Test Interferences Drug may cause falsely elevated serum digoxin values with radioimmunoassay (assay specific) for measuring digoxin.

 Adverse Reactions

CNS: Drowsiness; lethargy; headache; mental confusion; ataxia. DERM: Maculopapular or erythematous cutaneous eruptions; urticaria. GI: Cramping; diarrhea; gastric bleeding; gastric ulceration; gastritis; vomiting. GU: Inability to achieve or maintain erection. HEMA: Agranulocytosis. META: Hyperchloremic metabolic acidosis in decompensated hepatic cirrhosis. OTHER: Gynecomastia; irregular menses or amenorrhea; postmenopausal bleeding; hirsutism; deepening of voice; drug fever; carcinoma of breast.

 Precautions

Pregnancy: Category D. Lactation: Excreted in breast milk. Electrolyte imbalances and BUN increase: Hyperkalemia (serum potassium > 5.5 mEq/L), hyponatremia, hypochloremia and increases in BUN may occur.

 Administration/Storage

• If single dose is prescribed, administer in morning.
• Take medication with food.
• May crush tablets and administer as suspension.
• Suspension is stable for 30 days under refrigeration. Protect from light.
• Store tablets at room temperature.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Assess fluid and electrolyte status prior to therapy.
• Monitor potassium levels. If level is > 5.5 mEq/L, withhold medication and notify physician.
• Monitor serum electrolytes, I&O, weight and BP daily.
• Monitor ABGs, liver and renal function studies.
• If deep rapid respirations or headaches develop, notify physician.
• Assess urinary status. If patient develops frequency, dysuria, edema or reduced urinary output, notify physician.
• Assess for any changes in hepatic status. If patient appears jaundiced and mentally confused, notify physician.
• If nausea, vomiting, distention, diarrhea or anorexia occur, notify physician.
• Note any changes in neurologic status. If drowsiness, ataxia, lethargy, confusion or headache occurs, notify physician.

 Patient/Family Education

• 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 wks 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 wkly and to notify physician of any increase.
• Instruct patient to notify physician if new symptoms develop.
• Tell patient to report these symptoms to physician: 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.
• Instruct patient not to take prescription or otc medications without consulting physician.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts