Spiretic25 mg

Spiretic is an aldosterone receptor antagonist (potassium-sparing diuretic) used for the following indications, classified by strength of evidence:

Established / FDA-approved uses

• Edema associated with congestive heart failure, hepatic cirrhosis (with or without ascites), and nephrotic syndrome, when other measures are considered inadequate or inappropriate.
• Essential hypertension, usually as an add-on to other antihypertensive therapy.
• Primary hyperaldosteronism: for diagnostic testing and for long-term maintenance therapy in patients with discrete aldosterone-producing adrenal adenomas who are poor surgical candidates or awaiting surgery, and in those with bilateral micro- or macronodular adrenal hyperplasia.
• Hypokalemia, for treatment or prevention when other measures are inadequate.

Guideline-supported / combination-therapy uses

• As an add-on to standard therapy (ACE inhibitor/ARB and beta-blocker) in patients with NYHA Class III-IV heart failure with reduced ejection fraction, to reduce morbidity and mortality.
• Adjunct agent in resistant hypertension not adequately controlled on standard combination antihypertensive therapy.

Off-label uses

• Hirsutism and hormonal acne in women, based on its antiandrogenic activity (widely used off-label; not an FDA-approved indication).
• Selected patients with heart failure with preserved ejection fraction (HFpEF).

Spironolactone is formulated as oral tablets, commonly available in strengths of 25 mg, 50 mg, and 100 mg. In some markets an oral suspension is also available. Each dosage form contains Spironolactone as the active pharmaceutical ingredient, together with standard pharmaceutical excipients.

Spiretic is a synthetic steroidal aldosterone antagonist that has been used clinically for decades as a potassium-sparing diuretic. Unlike thiazide or loop diuretics, Spiretic works by directly blocking the action of aldosterone in the kidney, promoting sodium and water excretion while conserving potassium. Spiretic is used in the management of edematous conditions, hypertension, primary hyperaldosteronism, and as part of guideline-directed therapy for heart failure with reduced ejection fraction. It also has antiandrogenic properties that make it useful, off-label, for conditions such as hirsutism and acne in women.

Spiretic belongs to the therapeutic class of potassium-sparing diuretics and is specifically an aldosterone receptor (mineralocorticoid receptor) antagonist.

Spironolactone is a synthetic 17-lactone steroid that acts as a specific pharmacological antagonist of aldosterone, competitively binding to mineralocorticoid receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted renal tubule. By blocking aldosterone, Spironolactone increases the excretion of sodium and water while reducing the excretion of potassium and hydrogen ions, producing a mild diuretic and antihypertensive effect. Spironolactone also possesses antiandrogenic activity, partly by competing with androgens for receptor binding and by mild inhibition of androgen biosynthesis, which is the basis for its off-label use in hyperandrogenic skin conditions. In heart failure, blockade of aldosterone's effects on cardiac and vascular remodeling is thought to contribute to the mortality benefit seen with Spironolactone.

Spiretic tablets should be taken by mouth, preferably with food, which can enhance absorption and reduce gastrointestinal discomfort. Spiretic should be taken at the same time(s) each day as advised by the physician. Doses greater than 50 mg/day are often split into two doses. Spiretic should not be stopped abruptly without medical advice, particularly when used for heart failure or cirrhosis, as this may worsen the underlying condition.

• ACE inhibitors, ARBs, direct renin inhibitors, and potassium supplements/salt substitutes: concurrent use with Spiretic has an additive risk of significant hyperkalemia; requires close monitoring of serum potassium.
• Eplerenone and other potassium-sparing diuretics/agents: concurrent use with Spiretic is contraindicated due to markedly increased hyperkalemia risk (see Contraindications).
• NSAIDs: may reduce the diuretic and antihypertensive effect of Spiretic and increase the risk of hyperkalemia and acute kidney injury, especially in volume-depleted patients.
• Lithium: Spiretic reduces renal clearance of lithium, increasing the risk of lithium toxicity; concurrent use is generally avoided or requires close monitoring of lithium levels.
• Digoxin: Spiretic and its metabolites can interfere with certain digoxin assays and may alter digoxin's elimination half-life; monitor for signs of digoxin toxicity.
• Other antihypertensive agents and diuretics: additive hypotensive and diuretic/electrolyte effects when combined with Spiretic.
• Cholestyramine: concurrent use with Spiretic has been associated with hyperkalemic metabolic acidosis; avoid combination when possible.

Common

• Gynecomastia (dose- and duration-related; usually reversible on stopping Spiretic)
• Menstrual irregularities, breast tenderness in women
• Hyperkalemia (mild, dose-related)
• Gastrointestinal upset: nausea, vomiting, diarrhea, abdominal cramping
• Headache, dizziness, drowsiness, fatigue
• Decreased libido and erectile dysfunction in men

Less common / serious

• Severe hyperkalemia, which can cause cardiac arrhythmia (see Contraindications and Precautions)
• Hyponatremia and dehydration
• Elevated liver enzymes; hepatotoxicity (rare)
• Skin rash; rare severe cutaneous reactions
• Agranulocytosis (rare)

Pregnancy: Animal studies with Spiretic and its active metabolites have shown antiandrogenic effects, including feminization of male fetuses at high doses. Human data are limited. Spiretic should be used during pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus; a physician should always be consulted before use in pregnancy or if pregnancy is suspected while taking Spiretic.

Lactation: Spiretic's active metabolite (canrenone) is excreted in breast milk. Because of the potential for adverse effects in the nursing infant, a decision should be made, in consultation with a physician, whether to discontinue breastfeeding or discontinue Spiretic, taking into account the importance of the drug to the mother.

• Hyperkalemia: the most important risk with Spiretic; periodic monitoring of serum potassium is required, especially in patients with renal impairment, diabetes mellitus, or those taking other agents that raise potassium (see Interactions).
• Renal function: even without meeting the threshold for contraindication, reduced renal function significantly raises hyperkalemia risk with Spiretic; dose reduction, avoidance, and more frequent monitoring are needed as renal function declines.
• Tumorigenicity signal: chronic toxicity studies in rats given high doses of Spiretic showed an increase in certain tumors; clinical relevance to humans at therapeutic doses is uncertain, but Spiretic should be used at the lowest effective dose for the shortest duration consistent with the treatment goal, particularly for non-life-threatening conditions.
• Endocrine effects: antiandrogenic and antiestrogenic activity of Spiretic can cause gynecomastia and menstrual irregularities (see Side Effects).
• Metabolic acidosis: risk increased in patients with hepatic cirrhosis receiving Spiretic.
• Electrolyte and fluid monitoring: periodic monitoring of serum electrolytes is recommended throughout treatment with Spiretic.
• Dietary potassium: patients should avoid potassium-rich salt substitutes and excessive dietary potassium while taking Spiretic unless directed otherwise by a physician.
• Elderly patients: more susceptible to hyperkalemia and decline in renal function; use lower initial doses and monitor closely.

Acute overdose of Spiretic may present with drowsiness, mental confusion, gastrointestinal disturbances (nausea, vomiting, diarrhea), skin rash, and signs of electrolyte disturbance such as hyperkalemia (muscle weakness, irregular heartbeat) or, less commonly, hyponatremia and dehydration. There is no specific antidote for Spiretic overdose. If overdose is suspected, seek immediate medical attention or contact emergency services / a poison control center right away. Management is supportive and should be provided in a medical facility, including monitoring and correction of electrolyte and fluid balance and cardiac monitoring; Spiretic is not effectively removed by hemodialysis.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Renal impairment

Spiretic is contraindicated in anuria and severe/acute renal impairment (see Contraindications). In milder renal impairment, use Spiretic with caution, at reduced doses, with frequent monitoring of serum potassium and renal function.

Hepatic impairment

Use Spiretic with caution in patients with hepatic cirrhosis due to increased risk of electrolyte disturbance and metabolic acidosis; close monitoring is required.

Elderly

Elderly patients are more susceptible to hyperkalemia and decline in renal function with Spiretic; start at lower doses and monitor closely.

Pediatric

See Pediatric Uses for age- and weight-based dosing information for Spiretic.

Duration of treatment with Spiretic varies by indication: a short initial trial (e.g., about 5 days) may be used to assess response in edema, while chronic conditions such as heart failure, cirrhotic ascites, primary hyperaldosteronism, and resistant hypertension typically require long-term or indefinite maintenance therapy. The prescribing physician should periodically review the continued need for Spiretic based on clinical response and monitoring of serum potassium and renal function.

Aldosterone Receptor Antagonists; Potassium-Sparing Diuretics.

Spironolactone acts as a competitive antagonist of aldosterone at mineralocorticoid receptors in the distal convoluted renal tubule, blocking aldosterone-mediated sodium reabsorption and potassium/hydrogen ion excretion. This results in increased sodium and water excretion with potassium conservation. Spironolactone also exerts antiandrogenic effects through androgen receptor antagonism and mild inhibition of androgen synthesis.

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Spiretic is used in pediatric patients for edema associated with conditions such as nephrotic syndrome, congestive heart failure, and hepatic cirrhosis, typically at a dose of about 1-3.3 mg/kg/day given in divided doses, individualized to response and tolerability. Safety and efficacy of Spiretic for indications other than edema (e.g., hypertension, primary hyperaldosteronism, or off-label antiandrogenic use) have not been well established in children, and use for these purposes should occur only under specialist supervision. Regular monitoring of serum potassium and renal function is essential in pediatric patients receiving Spiretic.