Spironolactone

Generic Details

Generic Name

Spironolactone

Other Names

  • Aldactone
  • CaroSpir

Drug Class

  • Potassium-sparing diuretic
  • Aldosterone antagonist

Chemical Formula

C24H32O4S

Molecular Weight

416.574 g/mol

Mechanism of Action

  • Blocks the effects of aldosterone in the distal tubules of the kidneys, leading to increased excretion of water and sodium while conserving potassium.

Indications

  • Hypertension
  • Edema associated with congestive heart failure
  • Edema associated with cirrhosis of the liver
  • Nephrotic syndrome
  • Primary hyperaldosteronism
  • Hypokalemia

Common Dosage Forms

  • Tablet
  • Suspension

Typical Dosage

  • 25-200 mg per day in 1-2 divided doses for hypertension
  • 100-400 mg per day in 1-2 divided doses for edema

Pediatric Dosage

  • Dosage based on weight and condition, consult pediatrician

Geriatric Dosage

  • Lower starting doses may be required due to decreased renal function in elderly patients

Side Effects

  • Hyperkalemia
  • Gynecomastia
  • Menstrual irregularities
  • Impotence
  • Breast tenderness
  • Dizziness
  • Drowsiness

Contraindications

  • Anuria
  • Hyperkalemia
  • Renal impairment
  • Addison's disease

Pregnancy Category

  • Category C - Risk cannot be ruled out

Lactation Safety

  • Considered compatible with breastfeeding

Drug Interactions

  • NSAIDs can reduce the diuretic, natriuretic, and antihypertensive effects
  • ACE inhibitors, angiotensin II receptor blockers, and direct renin inhibitors can increase the risk of hyperkalemia

Overdose Symptoms

  • Hyperkalemia
  • Hyponatremia
  • Dehydration

Antidote for Overdose

  • Treatment is supportive and symptomatic

Storage Conditions

  • Store at room temperature away from moisture and heat

Pharmacokinetics

  • Absorption: 50-90% absorbed from the GI tract
  • Distribution: Highly protein-bound
  • Metabolism: Metabolized in the liver to active metabolites
  • Excretion: Primarily renal excretion

Precautions

  • Monitor electrolytes regularly, especially potassium levels
  • Consider dosage adjustments in hepatic impairment
  • Avoid potassium supplements and salt substitutes containing potassium

Warnings

  • Hyperkalemia risk
  • May cause tumors in animal studies

Others

  • Can be used as an antiandrogen in the treatment of hirsutism and acne in women