amiloride hydrochloride: clinical use

Prescribing considerations

• Assess renal function and baseline electrolytes, especially potassium, before treatment.
• Use particular caution in older or acutely unwell people and in diabetes, hepatic impairment, renal impairment or conditions associated with acidosis.
• Review amiloride before a glucose-tolerance test because temporary interruption is specified in the product information.
• In cirrhosis, avoid abrupt fluid and electrolyte shifts and watch for worsening jaundice or hepatic encephalopathy.

Contraindications and cautions

• Across the selected products: hyperkalaemia, hypersensitivity and concomitant potassium supplements or other potassium-conserving agents.
• Severe renal impairment is contraindicated for the selected tablet; the oral-solution information additionally lists anuria, acute renal failure, severe progressive renal disease, diabetic nephropathy and Addison's disease.
• The oral solution is unsuitable in hereditary fructose intolerance because it contains maltitol; the tablet contains lactose and has restrictions for specified hereditary sugar-intolerance disorders.

Monitoring

• Serum potassium, sodium and other electrolytes.
• Renal function and blood urea, with closer monitoring after clinical deterioration or addition of interacting medicines.
• Blood pressure, volume status and diuretic response.
• Clinical and laboratory evidence of hyperkalaemia; an ECG may not always detect it.
• Neurological state and liver status in advanced hepatic disease.

Clinical pharmacology

Amiloride is a mild potassium-sparing natriuretic that inhibits electrogenic sodium entry through epithelial sodium channels in the distal nephron. It is incompletely absorbed, is not metabolised and is excreted largely unchanged by the kidneys.

Formulation and product differences

• The selected presentations comprise an oral tablet and an oral solution.
• The tablet contains lactose.
• The oral solution contains maltitol, methyl and propyl hydroxybenzoates, propylene glycol and a small amount of ethanol; the parabens may cause delayed allergic reactions.
• Use an appropriate oral measuring device for the solution.

Oral solution

Route: Oral

Strengths: 5 mg/5 mL

Tablet

Route: Oral

Strengths: 5 mg