Spironolactone
Class: diuretic – aldosterone antagonist, potassium sparing diuretic
Indications (NB some may be unlicensed): peripheral oedema associated with portal hypertension and hyperaldosteronism resistant hypertension, congestive heart failure, hirsutism, primary hyperaldosteronism, malignant ascites
Contraindications/cautions: moderate/severe renal dysfunction, hyperkalaemia, hyponatraemia; avoid concurrent use with K supplements
Adverse reactions: common: GI upset, drowsiness, dizziness, hyperkalaemia; less common: rashes, headache, confusion, impotence, gynaecomastia, hyponatraemia
Metabolism/clearance: metabolised in liver to active metabolites which are excreted partially by the kidneys
Interactions:
- increased risk of hyperkalaemia with NSAIDs (e.g. diclofenac), ACE inhibitors (e.g. cilazapril, quinapril), potassium supplements
- increased clinical effect/toxicity of digoxin may occur via increased digoxin concentrations
| Dosing: | ||
|---|---|---|
| oral: | malignant ascites | start with 100 mg mane; increase by 100 mg mane every 3 to 5 days if required (max. 400 mg daily) |
| subcut/rectal : | not available |
Syringe driver: not available
Mechanism of action: inhibits aldosterone causing naturesis and potassium retention
Peak response: aldosterone antagonism: 6 to 8 hours reduced ascites: 10 to 25 days
Notes:
- paracentesis may be necessary in malignant ascites
- monitor body weight and renal function
- take with food to minimise gastric irritation
- halve dose in patients with ascites and moderate renal impairment (eGFR 30 to 59 mL/min/1.73m^2 )