Amiloride Drug Profile

What is Amiloride?

Amiloride is a potassium-sparing diuretic medication that helps the body eliminate excess sodium and water while retaining potassium. Unlike other diuretics that can cause dangerous potassium loss, amiloride helps maintain normal potassium levels in the blood. It is primarily used to treat high blood pressure and fluid retention, often in combination with other diuretic medications.

Uses

Amiloride is prescribed for several medical conditions:

• Hypertension (high blood pressure): Often used in combination with thiazide diuretics to provide blood pressure control while preventing potassium depletion
• Edema management: Helps reduce fluid retention associated with heart failure, liver disease, or kidney disorders
• Prevention of hypokalemia: Used alongside other diuretics to prevent dangerous drops in blood potassium levels
• Primary aldosteronism: Helps counteract the effects of excess aldosterone hormone that causes sodium retention and potassium loss
• Lithium-induced diabetes insipidus: Can help reduce excessive urination caused by long-term lithium therapy

How it works

Amiloride works by blocking sodium channels in the kidneys’ collecting ducts, specifically targeting epithelial sodium channels. This action prevents sodium reabsorption, leading to increased sodium and water excretion while preserving potassium. By blocking these channels, amiloride reduces the electrical driving force that normally causes potassium loss, making it an effective potassium-sparing diuretic.

Side effects

Common side effects include:

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• Headache
• Dizziness
• Nausea and stomach upset
• Diarrhea
• Muscle cramps
• Fatigue or weakness
• Dry mouth
• Decreased appetite

Serious side effects requiring immediate medical attention:

• Hyperkalemia (dangerously high potassium levels)
• Severe dehydration or electrolyte imbalance
• Kidney function deterioration
• Irregular heartbeat or chest pain
• Severe dizziness or fainting

Warnings and precautions

• Kidney disease: Patients with impaired kidney function require careful monitoring and possible dose adjustments, as amiloride can worsen kidney problems and increase hyperkalemia risk
• Diabetes: Diabetic patients, especially those with kidney complications, face increased risk of dangerous potassium elevation
• Pregnancy and breastfeeding: Amiloride is classified as pregnancy category B, but should only be used when potential benefits outweigh risks; it passes into breast milk
• Elderly patients: Older adults may be more sensitive to electrolyte changes and require more frequent monitoring of kidney function and potassium levels
• Dehydration risk: Patients should maintain adequate fluid intake and avoid excessive heat exposure or intense exercise that could lead to dehydration

Interactions

Amiloride has several important drug interactions:

• ACE inhibitors and ARBs: Combination increases hyperkalemia risk by reducing aldosterone production
• Potassium supplements: Can lead to dangerous potassium accumulation when combined with amiloride
• NSAIDs: May reduce amiloride’s effectiveness and increase kidney toxicity risk
• Lithium: Amiloride can increase lithium blood levels, potentially causing lithium toxicity
• Digoxin: Changes in potassium levels can affect digoxin toxicity and effectiveness
• Salt substitutes containing potassium: Can contribute to hyperkalemia when used with amiloride
• Trimethoprim: May increase potassium levels when combined with amiloride
• Cyclosporine: Increases risk of hyperkalemia and kidney problems

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Dosage

Typical adult dosages for amiloride vary based on the condition being treated and individual patient factors. For hypertension and edema, the usual starting dose is 5mg once daily, which may be increased to 10mg daily if needed. When used in combination with other diuretics, doses typically range from 2.5mg to 10mg daily. The maximum recommended dose is generally 20mg per day. Dosage adjustments are often necessary for patients with kidney impairment or those taking multiple medications affecting electrolyte balance. Regular monitoring of kidney function and electrolyte levels is essential during treatment. All dosage decisions should be made by a qualified healthcare provider based on individual medical history and current health status.

Sources: FDA DailyMed drug labels (public domain), BNF, WHO Essential Medicines List. This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting or stopping any medication.

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