Spironolactone

Spironolactone is a potassium-sparing diuretic, which acts by antagonizing aldosterone. Low doses of spironolactone have been shown to benefit patients with severe congestive heart failure who are already receiving an ACE inhibitor and a diuretic. It is also of value in the treatment of oedema and ascites in cirrhosis of the liver.

Uses
Congestive heart failure
Oedema and ascites in liver cirrhosis

Contraindications
Hyperkalaemia
Hyponatraemia
Severe renal failure
Addison’s disease

Administration
• Congestive heart failure
  Orally: 25–50 mg once daily
• Oedema and ascites in liver cirrhosis
  Orally: 100–400 mg once daily

If IV route is needed, use potassium canrenoate (unlicensed drug). Conversion: potassium canrenoate 140 mg is equivalent to spironolactone 100 mg.Administer by IV bolus via a large vein at a maximum rate of 100 mg/min, otherwise administer via IV infusion in 250 ml of glucose 5% over 90 min

Monitor: serum sodium, potassium and creatinine

Adverse effects
Confusion
Hyperkalaemia (unlikely to occur with congestive heart failure dose)
Hyponatraemia
Abnormal LFT
Gynaecomastia (usually reversible)
Rashes
Cautions
Porphyria
Renal impairment (risk of hyperkalaemia)
Concurrent use of:
• ACE inhibitor (risk of hyperkalaemia)
• angiotensin-II antagonist (risk of hyperkalaemia)
• digoxin ( plasma concentration of digoxin)
• ciclosporin (risk of hyperkalaemia)
• lithium ( plasma concentration of lithium)

Organ failure
Renal: risk of hyperkalaemia; use with caution in severe renal failure
Hepatic: may precipitate encephalopathy

Renal replacement therapy
CVVH not dialysable, dose as in CC 10–20 ml/min, i.e. half normal dose. HD/PD not dialysable, use with caution; 25 mg three times per
week appears safe.