Spironolactone belongs to a group of medicines called potassium sparing diuretics (water tablets).
Spironolactone is used for the treatment of
- ascites and edema (swelling in the abdomen due to fluid retention) associated with liver disease (cirrhosis) or malignant disease
- nephrotic syndrome (a kidney disease that causes too much fluid in your body)
- diagnosis and treatment of a hormone condition called primary aldosteronism (excessive production of aldosterone, a steroid produced by the adrenal gland)
- congestive heart failure (inability of the heart to pump blood around the body, resulting in swelling of veins and organs with blood)
 BRAND NAMES
 MECHANISM OF ACTION
Spironolactone is potassium sparing diuretic that acts by antagonism of aldosterone to the renal mineralocorticoid receptor in the distal renal tubules.
The primary function of Aldosterone is to retain sodium and excrete potassium in the kidneys, therefore, Spironolactone causes increased amounts of sodium and water to be excreted, while potassium is retained.
Spironolactone acts both as a diuretic and as an antihypertensive and provide effective therapy for edema and ascites in conditions like congestive heart failure, hepatic cirrhosis, hyperaldosteronism and nephrotic syndrome.
Spironolactone possesses also an anti-androgenic effect which could be due to a peripheral antagonism of androgens.
- Primary hyperaldosteronism for:
- Establishing the diagnosis of primary hyperaldosteronism by therapeutic trial.Short-term preoperative treatment of patients with primary hyperaldosteronism.
- Long-term maintenance therapy for patients with discrete aldosterone-producing adrenal adenomas who are judged to be poor operative risks or who decline surgery.
- Long-term maintenance therapy for patients with bilateral micro or macronodular adrenal hyperplasia (idiopathic hyperaldosteronism).
- Edematous conditions for patients with:
- Congestive heart failure: For the management of edema and sodium retention when the patient is only partially responsive to, or is intolerant of, other therapeutic measures.
- For patients with congestive heart failure taking digitalis when other therapies are considered inappropriate.
- Cirrhosis of the liver accompanied by edema and/or ascites: Aldosterone levels maybe exceptionally high in this condition. Spironolactone is indicated for maintenance therapy together with bed rest and the restriction of fluid and sodium.
- Nephrotic syndrome: For nephrotic patients when treatment of the underlying disease, restriction of fluid and sodium intake, and the use of other diuretics do not provide an adequate response.
- Essential hypertension
- Hypokalemia: For the treatment of patients with hypokalemia when other measures are considered inappropriate or inadequate. Spironolactone is also indicated for the prophylaxis of hypokalemia in patients taking digitalis when other measures are considered inadequate or inappropriate.
- Severe heart failure (NYHA class III – IV): To increase survival, and to reduce the need for hospitalization for heart failure when used in addition to standard therapy.
- Hirsutism: Spironolactone is effective in the treatment of females with hirsutism, an androgen-related increase in facial and body hair. A reduction in hair growth, hair shaft diameter and hair pigmentation is seen.
- Edema in adults (congestive heart failure, hepatic cirrhosis, or nephrotic syndrome): Initial daily dosage is 100 mg. Dosage range: 25-200 mg daily
- Hypertension: Initial daily dosage is 50-100 mg
- Hypokalemia: 25-100 mg daily
- Female Hirsutism: 100-200 mg daily in divided doses. however 50 mg daily has also been shown to be effective
Spironolactone is contraindicated for patients with anuria, acute renal insufficiency, significant impairment of renal function, hyperkalemia, pregnancy, hypersensitivity to spironolactone or with concomitant use of eplerenone.
 WARNINGS AND PRECAUTIONS
- Potassium supplementation is not recommended (Risk of hyperkalemia)
- Monitor and manage serum potassium in patients with severe heart failure. (Hyperkalemia may be fatal in these patients)
- Gynecomastia may develop and it is related to both dosage level and duration of therapy and is normally reversible when Spironolactone is discontinued. In rare instances, some breast enlargement may persist.
- Potassium-sparing diuretics: Spironolactone should not be administered concurrently with other potassium-sparing diuretics (e.g. Amiloride, Eplerenone, Potassium canrenoate and Triamterene)
- ACE inhibitors: Extreme caution should be exercised when Spironolactone is given concomitantly with ACE inhibitors because of a risk of severe hyperkalemia.
- NSAIDs: Extreme caution should be exercised when Spironolactone is given concomitantly with NSAIDs because of a risk of severe hyperkalemia.
- Digoxin: Spironolactone has been shown to increase the half-life of digoxin. This may result in increased serum digoxin levels and subsequent digitalis toxicity. It may be necessary to reduce the maintenance dose of digoxin when Spironolactone is administered.
 PREGNANCY AND LACTATION
- Pregnancy Category C (US). Spironolactone should not be used in pregnancy. Women of child-bearing potential should employ adequate contraception, and the drug should be stopped if pregnancy occurs or is suspected.
- During lactation, if the use of Spironolactone is deemed essential an alternative method of infant feeding should be instituted.
 SIDE EFFECTS
- Stomach upset and Gastritis
- Lightheadedness and dizziness
- Steroid-like effects
- Menstrual irregularity and breast enlargement and tenderness (related to the anti-androgenic mechanism)
- Gynecomastia (See warnings and precautions)
- K+ retention (Hyperkalemia)
- Leg cramps
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|Nonselective (Beta1, Beta2 and Alpha1 blockers)||Carvedilol (Dilatrend) • Labetalol (Trandate)|
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Aldosterone receptor antagonists: Potassium canrenoate • Eplerenone (Inspra) • Spironolactone (Aldactone)
|Combination therapy||Amiloride/Hydrochlorothiazide (Moduretic) • Spironolactone/Hydrochlorothiazide (Aldactazide)|
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