Class: Potassium-Sparing Diuretic
Dosage Forms. Tablet: 25 mg, 50 mg, 100 mg
Common FDA Label Indication, Dosing, and Titration.
1. Ascites, cirrhosis of liver: 100 mg po daily in single or divided doses, may titrate to 400 mg/d
2. CHF: 100 mg po daily in single or divided doses, may titrate to 400 mg/d
3. Nephrotic syndrome: 100 mg po daily in single or divided doses, may titrate to 400 mg/d
4. Hypertension: 50-100 mg po daily in single or divided doses, may titrate to 400 mg/d
5. Hypokalemia: 25-100 mg po daily
1. Acne vulgaris: 50-200 mg po daily
2. Hirsutism: 50-200 mg po daily for 20 d/mo
MOA. Spironolactone is a steroidal competitive aldosterone antagonist that acts from the interstitial side of the distal and collecting tubular epithelium to block sodium-potassium exchange, producing a delayed and mild diuresis. The diuretic effect is maximal in states of hyperaldosteronism. Excretion of sodium and chloride excretion is increased; excretion of potassium and magnesium is decreased. Spironolactone has mild antihypertensive activity and has demonstrated a beneficial effect in class III and IV CHF.
Drug Characteristics: Spironolactone
Medication Safety Issues: Spironolactone
Drug Interactions: Spironolactone
Adverse Reactions: Spironolactone
Efficacy Monitoring Parameters. Decreased BP, reduction in edema, weight.
Toxicity Monitoring Parameters. Monitor SCr, potassium levels, ECG if symptoms of hyperkalemia occur.
Key Patient Counseling Points. May cause dizziness. Avoid driving, using machinery, or doing anything else that could be dangerous if not alert. Report signs/symptoms of hyperkalemia (muscle weakness, fatigue, bradycardia) and hyponatremia (confusion, dry mouth, thirst, weakness, hypotension, decreased urination). Avoid potassium supplements, foods/salt substitutes that are high in potassium. Avoid alcohol and NSAIDs.
Clinical Pearls. Reduce dose when used in combination with other diuretics. May use loading dose of 2-3 times the daily dose on first day for faster diuresis. Tablets smell like peppermint . . . no kidding.