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Spironolactone
Aka: Spironolactone, Aldactone
- Definition
- Potassium-Sparing Diuretic via aldosterone blockade
- Indications
- Left-sided Congestive Heart Failure
- First line agent in conjunction with ACE Inhibitor
- Monitor for Hyperkalemia (esp. with ACE Inhibitor)
- Edematous states
- Cirrhosis
- Primary Hyperaldosteronism
- Nephrotic Syndrome
- Hyperandrogenism in women
- Hirsutism
- Polycystic Ovary Disease
- Refractory Hypertension
- See Hypertension Combination Therapy
- Contraindications
- Anuria
- Renal insufficiency with Serum Creatinine over 2.4
- Hyperkalemia
- Drug Interactions
- Increased Serum Potassium (Hyperkalemia risk)
- Potassium Supplementation
- NSAIDs
- ACE Inhibitor
- Increases Digoxin half-life
- Salicylates decreases Spironolactone effect
- Dosing
- Congestive Heart Failure: 25 to 50 mg PO qd
- Diuretic: 50-100 mg PO per day divided qd to bid
- Hyperandrogenism: 50 mg PO bid
- Hypertension: 12.5 to 50 mg PO qd
- Monitoring
- Serum Potassium
- Renal Function (Serum Creatinine)
- Pharmacokinetics
- Primarily renal excretion
- Half-life: 14 to 16 hours
- Mechanism
- General
- Spironolactone is a aldosterone competitive inhibitor
- Acts at distal convoluted renal tubule
- Congestive Heart Failure
- Works synergistically with ACE Inhibitors in CHF
- ACE Inhibitors block Angiotensin II production
- Renal response is to increase Aldosterone
- Spironolactone blocks aldosterone escape
- References
- Margo (2001) Am Fam Physician 64(8):1393-8
- Pitt (1999) N Engl J Med 341:709-17