Amiloride

Generic name:

Amiloride

Drug class:

Potassium-sparing diuretic; epithelial sodium channel blocker

Dosage form:

• Tablets: 5 mg
• Oral solution: varies by formulation; consult label

Root of administration:

Oral

Dose:

• Initial: 5 mg once daily
• Typical: 5–10 mg once or twice daily
• Maximum: 20 mg/day
• Adjustment: based on response and serum electrolytes

Mechanism of action:

Blocks epithelial sodium channels in the distal convoluted tubule and collecting duct, reducing sodium reabsorption and decreasing potassium and hydrogen ion excretion.

Drug usage cases:

• Edema associated with congestive heart failure
• Mild hypertension (monotherapy or adjunct)
• Edema in hepatic cirrhosis
• Nephrotic syndrome-associated edema
• Off-label: lithium-induced nephrogenic diabetes insipidus
• Off-label: adjunct in cystic fibrosis inhalation therapy

Drug contra indications:

• Hyperkalemia (serum K⁺ >5.5 mEq/L)
• Anuria
• Severe renal impairment (creatinine clearance <10 mL/min)
• Addison’s disease
• Concomitant potassium supplements or other potassium-sparing diuretics

Side effects:

• Hyperkalemia
• Dizziness, headache
• Nausea, vomiting, diarrhea, abdominal cramps
• Dehydration
• Hyponatremia
• Muscle cramps, weakness
• Rash, photosensitivity
• Orthostatic hypotension
• Chest pain
• Electrolyte disturbances (Mg²⁺, Ca²⁺)

Warnings:

• Monitor serum electrolytes and renal function regularly
• Risk of severe hyperkalemia, especially with ACE inhibitors, ARBs, NSAIDs
• Use caution in elderly and those with renal or hepatic impairment
• Avoid rapid IV administration
• Risk of volume depletion and hypotension
• Monitor blood pressure and fluid status

Use during pregnancy or breastfeeding:

Pregnancy: Varies by indication; consult label. Animal studies show adverse effects on fetal development at high doses; use only if potential benefit justifies risk to fetus. Breastfeeding: Unknown if excreted in human milk; use with caution. Monitor infant for electrolyte disturbances if used during lactation.