Furosemide+Spironolactone

Introduction: Furosemide + Spironolactone is a combination diuretic used for the treatment of essential hypertension, chronic congestive heart failure, hepatic cirrhosis with ascites, edema and hyperaldosteronism.

How it works: Spironolactone (potassium sparing diuretic) and Furosemide (loop diuretic) have different but complementary mechanisms and sites of action. When given together they produce additive or synergistic diuretic effect.

Important Information: Furosemide induces potassium loss. Spironolactone antagonises aldosterone action to reduce excessive potassium loss induced by Furosemide.

• Essential hypertension
• Chronic congestive heart failure
• Hepatic cirrhosis - with collection of fluid in the abdominal cavity (ascites)
• Edema - swelling due to excess fluid retention
• Hyperaldosteronism
• Resistant edema associated with secondary hyperaldosteronism

Potassium-sparing diuretics, Potassium-sparing diuretics & Aldosterone antagonists

Loop diuretic + Potassium-sparing diuretic

Spironolactone (potassium sparing diuretic) and Furosemide (loop diuretic) have different but complementary mechanisms and sites of action. Furosemide inhibits the Na+/K+/2Cl- co-transporter in the ascending Loop of Henle and blocks reabsorption of sodium, potassium and chloride ions; thereby increasing sodium and water excretion. This induces potassium loss. Spironolactone inhibits sodium reabsorption in exchange for potassium at the distal tubule by antagonising aldosterone action, greatly favouring sodium excretion and reducing excess potassium loss induced by Furosemide.

Furosemide inhibits sodium and chloride reabsorption in the loop of Henle to produce diuresis. Spironolactone acts as an aldosterone antagonist in the distal tubule to increase sodium excretion and retain potassium.

Adult Dose:

• Furosemide 20 mg + Spironolactone 50 mg: 1 to 4 tablets daily (20-80 mg Furosemide and 50-200 mg Spironolactone) according to patient response.
• Furosemide 40 mg + Spironolactone 50 mg: For previously stabilized patients requiring higher dosage, 1-2 tablets daily (40-80 mg Furosemide and 50-100 mg Spironolactone).

Children: Not suitable for use in children.

Elderly: May be excreted more slowly in the elderly.

* Use as directed by the registered physician

Oral tablet. Can be taken with or without food. Swallow whole.

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and follow your regular schedule.

Common Side Effects:

• Headache and drowsiness
• Gastrointestinal distress - including cramp and diarrhoea
• Ataxia
• Mental confusion
• Skin rashes
• Gynaecomastia - not uncommon
• Hirsutism, deepening of voice, menstrual irregularities, impotence

Serious Side Effects: Hyperkalemia, hyponatremia, dehydration, cardiac arrhythmias.

Precautions:

• Caution in patients liable to electrolyte deficiency.
• Use with caution in diabetes, enlarged prostate, hypotension and hypovolemia.
• Increased risk of hyperkalemia with ACE inhibitors or potassium salts.

Contraindications:

• Anuria
• Acute renal insufficiency
• Rapidly deteriorating or severe impairment of renal function (CrCl <30 ml/min)
• Hyperkalemia
• Addison's disease
• Hypersensitivity to Spironolactone, Furosemide or sulphonamides

Drug Interactions:

• ACE inhibitors or potassium salts: Increased risk of hyperkalemia.
• Spironolactone: Increases digoxin levels (may cause digitalis toxicity).
• Corticosteroids: May cause hypokalemia.
• NSAIDs (indomethacin): May reduce or abolish diuretic and antihypertensive effects of Furosemide.
• Aminoglycosides: Increased risk of ototoxicity.

Food Interactions: No interaction found/established.

Use in Pregnancy: Spironolactone and its metabolites may cross the placental barrier. Furosemide may cause fetal abnormalities. Weigh benefits against potential risks.

Use in Lactation: Spironolactone metabolites detected in breast milk. Furosemide is excreted in breast milk. Breast-feeding should be discontinued if treatment is essential.

Pediatric Use: Not suitable for use in children.

Geriatric Use: May be excreted more slowly in the elderly. Titrate dosage.

Renal & Hepatic Impairment: Contraindicated in severe renal impairment (CrCl <30 ml/min). Caution in liver disease.

Overdose: Excessive diuresis may result in dehydration and circulatory collapse, especially in elderly patients. Serious depletion of potassium and magnesium may lead to cardiac arrhythmias.

Storage: Keep below 30°C, away from light and moisture. Keep out of reach of children.

Furosemide + Spironolactone Tablet