Amiloride

Potassium-sparing Diuretic·Cardiovascular - Diuretics

Prevention or treatment of hypokalemia caused by other diuretics

PBSK-SPARINGKaluril, Moduretic (combo with HCTZ)5 mg tabletS4+1

Max Dose

20 mg/day

Half-life

6–9 h

Hyperkalemia

HIGH RISK

Renal Adj.

MANDATORY

Rapid Summary

Overview

Epithelial sodium channel (ENaC) blocker. A weak diuretic used almost exclusively to counteract the potassium-wasting effects of loop and thiazide diuretics.

Maximum Dose

Max 20 mg/day

Clinical Focus

Very high risk of hyperkalemia if given alongside ACEi/ARBs or in renal failure.

Bottom Line

Amiloride is a potassium-sparing diuretic used to counteract thiazide/loop-induced hypokalaemia, but must be avoided in renal impairment due to dangerous hyperkalaemia risk.

Formulation & Access

Brand Names

Kaluril, Moduretic (combo with HCTZ)

Oral Routes

Tablets (5 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Prevention or treatment of hypokalemia caused by other diuretics.

Off-Label

OFF

Lithium-induced nephrogenic diabetes insipidus.

Clinical Place

Niche utility. Largely superseded by Spironolactone/Eplerenone which offer actual mortality benefits in heart failure.

Quick reference

Class & Role

Potassium-sparing Diuretic — Epithelial sodium channel (ENaC) blocker.

Route / Formulation

Tablets (5 mg). (Kaluril, Moduretic (combo with HCTZ))

Usual Dose & Max

PO 5-10 mg OD. Max 20 mg/day.

Key Indication Doses

Diuretic-induced Hypokalemia: PO 5-10 mg OD. Max 20 mg/day. Combination Therapy: Often formulated directly with HCTZ (e.g., Moduretic).

Best Uses

Amiloride is a potassium-sparing diuretic used to counteract thiazide/loop-induced hypokalaemia, but must be avoided in renal impairment due to dangerous hyperkalaemia risk.

Avoid / Cautions

Baseline hyperkalemia (K+ > 5.0), anuria, severe renal impairment (eGFR < 30). Pregnancy Category C.

Key Risks

Electrolytes: Hyperkalemia (can be severe and rapid). Hyponatremia. Gastrointestinal: Nausea, anorexia. Neurological: Headache, weakness.

Key Interactions

ACEi, ARBs, Spironolactone, K+ supplements. Do not use together unless under intense specialist monitoring. NSAIDs (exacerbate renal failure and hyperkalemia).

Monitoring

Regular U&E monitoring. Cease drug if K+ > 5.0. Monitor BP.

Clinical Pearl

Amiloride is uniquely useful for patients on Lithium who develop polyuria (diabetes insipidus). It blocks the ENaC channel where Lithium enters the collecting duct cells, halting the toxicity.

Access

Kaluril, Moduretic (combo with HCTZ)5 mg tablet

Brand: Kaluril, Moduretic (combo with HCTZ)
Formulation: Tablets (5 mg)

Amiloride

Potassium-sparing Diuretic·Cardiovascular - Diuretics

Prevention or treatment of hypokalemia caused by other diuretics

PBSK-SPARINGKaluril, Moduretic (combo with HCTZ)5 mg tabletS4+1

Max Dose

20 mg/day

Half-life

6–9 h

Hyperkalemia

HIGH RISK

Renal Adj.

MANDATORY

Rapid Summary

Overview

Epithelial sodium channel (ENaC) blocker. A weak diuretic used almost exclusively to counteract the potassium-wasting effects of loop and thiazide diuretics.

Maximum Dose

Max 20 mg/day

Clinical Focus

Very high risk of hyperkalemia if given alongside ACEi/ARBs or in renal failure.

Bottom Line

Amiloride is a potassium-sparing diuretic used to counteract thiazide/loop-induced hypokalaemia, but must be avoided in renal impairment due to dangerous hyperkalaemia risk.

Formulation & Access

Brand Names

Kaluril, Moduretic (combo with HCTZ)

Oral Routes

Tablets (5 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Prevention or treatment of hypokalemia caused by other diuretics.

Off-Label

OFF

Lithium-induced nephrogenic diabetes insipidus.

Clinical Place

Niche utility. Largely superseded by Spironolactone/Eplerenone which offer actual mortality benefits in heart failure.

Quick reference

Class & Role

Potassium-sparing Diuretic — Epithelial sodium channel (ENaC) blocker.

Route / Formulation

Tablets (5 mg). (Kaluril, Moduretic (combo with HCTZ))

Usual Dose & Max

PO 5-10 mg OD. Max 20 mg/day.

Key Indication Doses

Diuretic-induced Hypokalemia: PO 5-10 mg OD. Max 20 mg/day. Combination Therapy: Often formulated directly with HCTZ (e.g., Moduretic).

Best Uses

Amiloride is a potassium-sparing diuretic used to counteract thiazide/loop-induced hypokalaemia, but must be avoided in renal impairment due to dangerous hyperkalaemia risk.

Avoid / Cautions

Baseline hyperkalemia (K+ > 5.0), anuria, severe renal impairment (eGFR < 30). Pregnancy Category C.

Key Risks

Electrolytes: Hyperkalemia (can be severe and rapid). Hyponatremia. Gastrointestinal: Nausea, anorexia. Neurological: Headache, weakness.

Key Interactions

ACEi, ARBs, Spironolactone, K+ supplements. Do not use together unless under intense specialist monitoring. NSAIDs (exacerbate renal failure and hyperkalemia).

Monitoring

Regular U&E monitoring. Cease drug if K+ > 5.0. Monitor BP.

Clinical Pearl

Amiloride is uniquely useful for patients on Lithium who develop polyuria (diabetes insipidus). It blocks the ENaC channel where Lithium enters the collecting duct cells, halting the toxicity.

Access

Kaluril, Moduretic (combo with HCTZ)5 mg tablet

Brand: Kaluril, Moduretic (combo with HCTZ)
Formulation: Tablets (5 mg)