Spironolactone

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Spironolactone (brand name Aldactone) — Diuretic, heart failure agent; Potassium-sparing diuretic, aldosterone antagonist.

Identification

• Therapeutic class: Diuretic, heart failure agent.
• Pharmacologic class: Potassium-sparing diuretic, aldosterone antagonist.

Pharmacology

• Mechanism of action: Competitively blocks aldosterone at the distal tubule, promoting sodium and water loss while retaining potassium.
• Onset / peak / duration: Onset gradual over 1 to 2 days; peak effect 2 to 3 days.
• Half-life / therapeutic level: Half-life about 1.4 hours (active metabolites longer); no routine level.

Clinical use

• Indications: Heart failure, edema, hyperaldosteronism, resistant hypertension, hirsutism, ascites.
• Usual dose, route, frequency: 25 to 100 mg PO daily.
• Maximum dose / adjustments: Up to about 200 mg/day; avoid in significant renal impairment due to hyperkalemia.

Safety

• Contraindications: Hyperkalemia, Addison disease, anuria, concurrent potassium supplements.
• Black box warning: Shown to be tumorigenic in chronic animal studies; avoid unnecessary use.
• Interactions: ACE inhibitors and ARBs (additive hyperkalemia), potassium supplements, NSAIDs, potassium salt substitutes (food), digoxin.
• Pregnancy / lactation: Use only if clearly needed.
• High-alert: No.

Adverse effects

• Common side effects: Hyperkalemia, gynecomastia, menstrual changes, dizziness.
• Serious effects to report: Severe hyperkalemia (muscle weakness, irregular heartbeat).
• Antidote / reversal: None; treat hyperkalemia.

Nursing process

• Assessment before administration: Potassium, renal function, blood pressure.
• Interventions during therapy: Avoid potassium supplements and salt substitutes; monitor potassium closely.
• Monitor: Serum potassium, renal function, blood pressure.
• Evaluation / expected outcome: Reduced edema with preserved potassium; improved heart failure.

Patient teaching

• Patient teaching: Avoid potassium-based salt substitutes; report breast tenderness.
• Notify provider if: Muscle weakness, palpitations, breast swelling.
• Administration tips: With food; avoid extra potassium.