Description

Spironolactone (potassium sparing diuretic) and Furosemide (loop diuretic) have different but complementary mechanisms and sites of action. Therefore, when given together they produce additive or synergistic diuretic. The Furosemide component inhibits the Na+/K+/2Cl- co-transporter in the ascending Loop of Henle and blocks the reabsorption of sodium, potassium and chloride ions; thereby increasing the quantity of sodium and the volume of water excreted in the urine. This characteristically induces potassium loss. The spironolactone component inhibits the reabsorption of sodium in exchange for potassium at the distal tubule by antagonising the action of aldosterone so that sodium excretion is greatly favoured and the excess loss of potassium, induced by the Furosemide, is reduced

Contraindicated in patients with anuria, acute renal insufficiency, rapidly deteriorating or severe impairment of renal function (creatinine clearance <30 ml/min), hyperkalaemia, Addison's disease and in patients who are hypersensitive to Spironolactone, Furosemide or sulphonamides.

Spironolactone may give rise to headache and drowsiness and gastrointestinal distress, including cramp and diarrhoea. Ataxia, mental confusion, and skin rashes have been reported as side effect. Gynaecomastia is not uncommon and in rare cases breast enlargement may persist. Other endocrine disorders including hirsutism, deepening of the voice, menstrual irregularities and impotence. Transient increase in blood-urea-nitrogen concentrations may occur and mild acidosis has been reported. Spironolactone may cause hyponatremia and hyperkalemia. Excessive diuresis may result in dehydration and reduction in blood volume with circulatory collapse with the possibility of vascular thrombosis and embolism particularly in elderly patients. Serious depletion of potassium and magnesium may lead to cardiac arrhythmias.

Pregnancy: Spironolactone and its metabolites may cross the placental barrier. The use of spironolactone in pregnant women requires that the anticipated benefit be weighed against the possible hazards to the mother and fetus. Animal teratology studies indicate that Furosemide may cause fetal abnormalities. Therefore, Furosemide should only be used in women in child bearing age when appropriate contraceptive measures are taken or if the potential benefits justify the potential risks to the fetus. Lactation: Metabolites of Spironolactone have been detected in breast milk. If use of Spironolactone is considered essential, an alternative method of infant feeding should be instituted. Furosemide is excreted in breast milk and breast-feeding should be discontinued if treatment is essential.

Caution should be taken in patients liable to electrolyte deficiency. This preparation should also be used with caution in diabetes, enlarged prostate, hypotension and in hypovolemia.

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

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.