Spironolactone

Administration

• Type: Antihypertensive; potassium sparing diuretic; aldosterone receptor antagonist
• Dosage Forms: 25,50,100
• Routes of Administration: Oral
• Common Trade Names: Aldactone

Adult Dosing

Edema

• 25-200mg/day PO divided QD-bid
  • For edema associated with CHF, cirrhosis, or nephrotic syndrome

Hypertension

• 25-50mg/day PO divided QD-bid
  • Start: 12.5mg PO QD

Hyperaldosteronism, primary

• 100-400mg PO QD

Hypokalemia, diuretic-induced

• 25-100mg/day PO divided QD-QID

CHF, NYHA Class III/IV

• 25mg PO QD
  • Use with standard treatment; may increase to 50mg/day after 8wk for worsening CHF if K stable
  • May decrease to 25mg qod if hyperkalemia; hold if K >5 mEq/L or creatinine >4mg/dL

Hirsutism, idiopathic

• 50-200mg PO QD
  • Off label use

Acne vulgaris

• 50-200mg PO QD
  • Start: 25mg PO QD
  • Off label use

Pediatric Dosing

Edema

• 1-3.3mg/kg/day PO divided QD-QID
  • Max: 3.3mg/kg/day up to 200mg/day
  • Off label use

Hyperaldosteronism test

• 125-375mg/m^2/day PO divided bid-QID
  • Max: 375mg/m^2/day
  • Off label use

Special Populations

• Pregnancy Risk Factor: C

Renal Dosing

• CrCl <10, anuria, or acute renal impairment: contraindicated

Hepatic Dosing

• Caution advised with hepatic impairment

Contraindications

• Allergy to class/drug
• CrCl <10
• anuria
• renal impairment, acute
• hyperkalemia
• Addison disease

Adverse Reactions

Serious

• anaphylaxis
• Stevens-Johnson syndrome
• toxic epidermal necrolysis
• drug reaction with eosinophilia and systemic sx
• vasculitis
• hepatotoxicity
• renal failure
• electrolyte imbalance
• hyperkalemia, severe
• arrhythmias
• leukopenia
• agranulocytosis
• thrombocytopenia

Common

• nausea/vomiting
• abdominal cramps/pain
• muscle cramps
• diarrhea
• headache
• confusion
• dizziness
• somnolence

Pharmacology

• Half-life: 1.3-2h (parent drug), 13.8-16.5h (active metabolites)
• Metabolism: Liver
• Excretion: Urine

Mechanism of Action

Antagonizes aldosterone receptors in the distal convoluted tubule, decreasing Na and water reabsorption and increasing K retention

See Also

• CHF
• Cirrhosis, Ascites

References

<Epocrates, UpToDate>