Amiloride
๐ About
Always check the BNF link here (or local formulary) before prescribing.
- ๐ Potassium-sparing diuretic, usually used in combination with other diuretics.
- Helps prevent potassium loss when loop or thiazide diuretics are used.
โ๏ธ Mode of Action
- Blocks epithelial sodium channels (ENaC) in the late distal convoluted tubule and collecting duct.
- โฌ๏ธ Sodium reabsorption โ โฌ๏ธ Sodium + water excretion.
- Reduces potassium excretion โ risk of hyperkalaemia.
๐ Indications
- ๐ซ Heart failure (usually with loop/thiazide to reduce Kโบ loss).
- ๐ง Oedema (hepatic cirrhosis, nephrotic syndrome).
- ๐ฉธ Hypertension (adjunct, rarely used alone).
- โ ๏ธ Ascites (in cirrhosis, often combined with spironolactone).
๐ Dose
| Name | Dose | Frequency | Route |
| Amiloride | 2.5 โ 10 mg | OD | PO |
๐ Interactions
- ๐ Monitor U&E and potassium closely.
- โ ๏ธ Risk of severe hyperkalaemia with other Kโบ-sparing drugs (spironolactone, ACE inhibitors, ARBs).
- ๐ Increases risk of lithium toxicity (reduced clearance).
- ๐ฉน NSAIDs may reduce renal function and blunt diuretic effect.
โ Contraindications
- ๐ซ Hyperkalaemia.
- ๐ซ Severe renal impairment or anuria.
- ๐ซ Addisonโs disease (already prone to high Kโบ).
โ ๏ธ Side Effects
- โฌ๏ธ Hyperkalaemia โ risk of arrhythmia.
- โฌ๏ธ Hyponatraemia.
- ๐ง Dehydration, dizziness, hypotension.
- ๐ง Lithium toxicity (if co-prescribed).
- ๐ฉบ NSAID-related nephrotoxicity (reduced renal perfusion).
- Rare: GI upset, headache, rash.
๐ References