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Aldactone (Spironolactone) Information

Aldactone, which contains the active ingredient spironolactone, is a medication classified as a potassium-sparing diuretic and a non-selective aldosterone receptor antagonist. It is primarily indicated for the treatment of hypertension (high blood pressure), often used in combination with other agents. It is also indicated for the treatment of edema (swelling) associated with congestive heart failure (CHF), cirrhosis, and the nephrotic syndrome. Critically, spironolactone is a foundational therapy to improve the survival of patients with severe heart failure (NYHA class III-IV) by reducing the risk of cardiovascular death and hospitalization. Spironolactone is administered orally, typically once or twice daily.

The mechanism of action for spironolactone involves competitively blocking the binding of aldosterone to the mineralocorticoid receptors (MR) in the distal convoluted tubule and collecting duct of the kidney. Aldosterone promotes the retention of sodium and water and the excretion of potassium. By blocking this receptor, spironolactone prevents sodium reabsorption, leading to a mild diuretic effect (sodium and water loss), while simultaneously sparing potassium (reducing potassium loss). In heart failure, blocking aldosterone receptors in the heart and blood vessels reduces fibrosis and inflammation, thereby reducing cardiovascular remodelling and improving long-term outcomes. However, spironolactone's non-selective nature means it also blocks androgen and progesterone receptors.

Aldactone Side Effects

Aldactone is generally well-tolerated, but side effects related to its action on potassium balance and its non-selective nature may occur. Common side effects often reported include gastrointestinal disturbances (nausea, vomiting, diarrhea), headache, and fatigue.

However, more serious side effects can occur, leading to significant monitoring protocols. If any of the following symptoms are experienced, the patient should stop taking the medication and seek immediate medical attention:
• Gynecomastia and Hormonal Changes: Due to its non-selective mechanism, spironolactone can cause painful gynecomastia (breast enlargement) in men, menstrual irregularities in women, and impotence.
• Hyperkalemia (Severe High Potassium) (Boxed Warning): The most serious risk is that significantly elevated serum potassium levels can cause dangerous, potentially fatal cardiac arrhythmias. This risk is highest in patients with impaired renal function, concurrent use of potassium supplements, or diabetes.
• Renal Impairment/Failure: In patients with moderate to severe renal impairment, the risk of hyperkalemia is substantially increased, and the drug should be used with extreme caution.
• Symptomatic Hypotension: Excessive lowering of blood pressure, especially when initiating therapy in patients who are volume-depleted, which may lead to fainting (syncope).

Aldactone Precautions

Due to the significant risk of severe hyperkalemia, Aldactone carries a Boxed Warning. It is contraindicated in all patients with hyperkalemia (serum potassium greater than 5.0 mEq/L at baseline), anuria (inability to urinate), acute renal insufficiency, or significant impairment of renal excretory function. Serum potassium levels and renal function (serum creatinine) must be checked before starting treatment, within the first week of starting or adjusting dose, and periodically thereafter. Patients should be cautioned against using potassium supplements or potassium-containing salt substitutes while on Aldactone. Because of its hormonal side effects, an alternative potassium-sparing diuretic may be preferred in some men. Patients with hepatic dysfunction should be monitored carefully as the drug can precipitate hepatic coma.

Do I need a prescription to order Aldactone?

Yes, a prescription is required from your physician to order Aldactone.