Aldactone

September 30, 2010 | Filed under: Medicines | Posted by:

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DRUG DESCRIPTION

What are the possible side effects of spironolactone (Aldactone)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using this medication and call your doctor at once if you have any of these serious side effects:

·numbness or tingly feeling;
·muscle pain or weakness;
·slow, fast, or uneven heartbeat;
·feeling drowsy, restless, or light-headed;
·urinating less than usual or not at all; …

Read All Potential Side Effects and See Pictures of Aldactone »

Aldactone oral tablets contain 25 mg, 50 mg, or 100 mg of the aldosterone antagonist spironolactone, 17-hydroxy-7α-mercapto-3-oxo-17α-pregn-4-ene-21-carboxylic acid γ-lactone acetate, which has the following structural formula:

Spironolactone is practically insoluble in water, soluble in alcohol, and freely soluble in benzene and in chloroform.

Inactive ingredients include calcium sulfate, corn starch, flavor, hypromellose, iron oxide, magnesium stearate, polyethylene glycol, povidone, and titanium dioxide.

Last reviewed on RxList: 8/19/2009

Aldactone Indications & Dosage

INDICATIONS

Aldactone (spironolactone) is indicated in the management of:

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. Aldactone is also indicated 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 may be exceptionally high in this condition. Aldactone is indicated for maintenance therapy together with bed rest and the restriction of fluid and sodium.

The 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

Usually in combination with other drugs, Aldactone is indicated for patients who cannot be treated adequately with other agents or for whom other agents are considered inappropriate.

Hypokalemia

For the treatment of patients with hypokalemia when other measures are considered inappropriate or inadequate. Aldactone 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.

Usage in Pregnancy. The routine use of diuretics in an otherwise healthy woman is inappropriate and exposes mother and fetus to unnecessary hazard. Diuretics do not prevent development of toxemia of pregnancy, and there is no satisfactory evidence that they are useful in the treatment of developing toxemia.

Edema during pregnancy may arise from pathologic causes or from the physiologic and mechanical consequences of pregnancy.

Aldactone is indicated in pregnancy when edema is due to pathologic causes just as it is in the absence of pregnancy (however, see PRECAUTIONS: Pregnancy). Dependent edema in pregnancy, resulting from restriction of venous return by the expanded uterus, is properly treated through elevation of the lower extremities and use of support hose; use of diuretics to lower intravascular volume in this case is unsupported and unnecessary.

There is hypervolemia during normal pregnancy which is not harmful to either the fetus or the mother (in the absence of cardiovascular disease), but which is associated with edema, including generalized edema, in the majority of pregnant women. If this edema produces discomfort, increased recumbency will often provide relief. In rare instances, this edema may cause extreme discomfort which is not relieved by rest. In these cases, a short course of diuretics may provide relief and may be appropriate.

DOSAGE AND ADMINISTRATION

Primary hyperaldosteronism

Aldactone may be employed as an initial diagnostic measure to provide presumptive evidence of primary hyperaldosteronism while patients are on normal diets.

Long test: Aldactone is administered at a daily dosage of 400 mg for three to four weeks. Correction of hypokalemia and of hypertension provides presumptive evidence for the diagnosis of primary hyperaldosteronism.

Short test: Aldactone is administered at a daily dosage of 400 mg for four days. If serum potassium increases during Aldactone administration but drops when Aldactone is discontinued, a presumptive diagnosis of primary hyperaldosteronism should be considered.

After the diagnosis of hyperaldosteronism has been established by more definitive testing procedures, Aldactone may be administered in doses of 100 to 400 mg daily in preparation for surgery. For patients who are considered unsuitable for surgery, Aldactone may be employed for long-term maintenance therapy at the lowest effective dosage determined for the individual patient.

Edema in adults (congestive heart failure, hepatic cirrhosis, or nephrotic syndrome)

An initial daily dosage of 100 mg of Aldactone administered in either single or divided doses is recommended, but may range from 25 to 200 mg daily. When given as the sole agent for diuresis, Aldactone should be continued for at least five days at the initial dosage level, after which it may be adjusted to the optimal therapeutic or maintenance level administered in either single or divided daily doses. If, after five days, an adequate diuretic response to Aldactone has not occurred, a second diuretic which acts more proximally in the renal tubule may be added to the regimen. Because of the additive effect of Aldactone when administered concurrently with such diuretics, an enhanced diuresis usually begins on the first day of combined treatment; combined therapy is indicated when more rapid diuresis is desired. The dosage of Aldactone should remain unchanged when other diuretic therapy is added.

Essential hypertension

For adults, an initial daily dosage of 50 to 100 mg of Aldactone administered in either single or divided doses is recommended. Aldactone may also be given with diuretics which act more proximally in the renal tubule or with other antihypertensive agents. Treatment with Aldactone should be continued for at least two weeks, since the maximum response may not occur before this time. Subsequently, dosage should be adjusted according to the response of the patient.

Hypokalemia

Aldactone in a dosage ranging from 25 mg to 100 mg daily is useful in treating a diuretic-induced hypokalemia, when oral potassium supplements or other potassium-sparing regimens are considered inappropriate.

Severe heart failure (NYHA class III – IV)

Treatment should be initiated with Aldactone 25 mg once daily if the patient’s serum potassium is ≤ 5.0 mEq/L and the patient’s serum creatinine is ≤ 2.5 mg/dL. Patients who tolerate 25 mg once daily may have their dosage increased to 50 mg once daily as clinically indicated. Patients who do not tolerate 25 mg once-daily dose may have their dosage reduced to 25 mg every other day. SEE WARNINGS: Hyperkalemia in patients with severe heart failure for advice on monitoring serum potassium and serum creatinine.

HOW SUPPLIED

Aldactone 25 mg tablets are round, light yellow, film-coated, with SEARLE and 1001 debossed on one side and ALDACTONE and 25 on the other side, supplied as:

NDC Number	Size
0025-1001-31	bottle of 100
0025-1001-51	bottle of 500
0025-1001-55	bottle of 2500

Aldactone 50 mg tablets are oval, light orange, scored, film-coated, with SEARLE and 1041 debossed on the scored side and ALDACTONE and 50 on the other side, supplied as:

NDC Number	Size
0025-1041-31	bottle of 100
0025-1041-34	carton of 100 unit dose

Aldactone 100 mg tablets are round, peach-colored, scored, film-coated, with SEARLE and 1031 debossed on the scored side and ALDACTONE and 100 on the other side, supplied as:

NDC Number	Size
0025-1031-31	bottle of 100
0025-1031-34	carton of 100 unit dose

Store below 77°F (25°C).

Distributed by: G.D. Searle LLC. Division of Pfizer Inc, NY, NY 10017. Revised January 2008.

Last reviewed on RxList: 8/19/2009

Aldactone Side Effects & Drug Interactions

SIDE EFFECTS

The following adverse reactions have been reported and, within each category (body system), are listed in order of decreasing severity.

Digestive: Gastric bleeding, ulceration, gastritis, diarrhea and cramping, nausea, vomiting.

Endocrine: Gynecomastia (see PRECAUTIONS), inability to achieve or maintain erection, irregular menses or amenorrhea, postmenopausal bleeding. Carcinoma of the breast has been reported in patients taking Aldactone but a cause and effect relationship has not been established.

Hematologic: Agranulocytosis.

Hypersensitivity: Fever, urticaria, maculopapular or erythematous cutaneous eruptions, anaphylactic reactions, vasculitis.

Metabolism: Hyperkalemia (see WARNINGS and PRECAUTIONS).

Nervous system/psychiatric: Mental confusion, ataxia, headache, drowsiness, lethargy.

Liver/biliary: A very few cases of mixed cholestatic/hepatocellular toxicity, with one reported fatality, have been reported with Aldactone administration.

Renal: Renal dysfunction (including renal failure).

DRUG INTERACTIONS

ACE inhibitors: Concomitant administration of ACE inhibitors with potassium-sparing diuretics has been associated with severe hyperkalemia.

Alcohol, barbiturates, or narcotics: Potentiation of orthostatic hypotension may occur.

Corticosteroids, ACTH: Intensified electrolyte depletion, particularly hypokalemia, may occur.

Pressor amines (e.g., norepinephrine): Aldactone reduces the vascular responsiveness to norepinephrine. Therefore, caution should be exercised in the management of patients subjected to regional or general anesthesia while they are being treated with Aldactone.

Skeletal muscle relaxants, nondepolarizing (e.g., tubocurarine): Possible increased responsiveness to the muscle relaxant may result.

Lithium: Lithium generally should not be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity.

Nonsteroidal anti-inflammatory drugs (NSAIDs): In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of loop, potassium-sparing and thiazide diuretics. Combination of NSAIDs, e.g., indomethacin, with potassium-sparing diuretics has been associated with severe hyperkalemia. Therefore, when Aldactone and NSAIDs are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.

Digoxin: Aldactone 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 and digitalization doses when Aldactone is administered, and the patient should be carefully monitored to avoid over or underdigitalization.

Drug/Laboratory test interactions

Several reports of possible interference with digoxin radioimmunoassay by Aldactone, or its metabolites, have appeared in the literature. Neither the extent nor the potential clinical significance of its interference (which may be assay-specific) has been fully established.

Last reviewed on RxList: 8/19/2009

Aldactone Warnings & Precautions

WARNINGS

Potassium supplementation

Potassium supplementation, either in the form of medication or as a diet rich in potassium, should not ordinarily be given in association with Aldactone therapy.

Excessive potassium intake may cause hyperkalemia in patients receiving Aldactone (see PRECAUTIONS: General). Aldactone should not be administered concurrently with other potassium-sparing diuretics. Aldactone, when used with ACE inhibitors or indomethacin, even in the presence of a diuretic, has been associated with severe hyperkalemia. Extreme caution should be exercised when Aldactone is given concomitantly with these drugs.

Hyperkalemia in patients with severe heart failure

Hyperkalemia may be fatal. It is critical to monitor and manage serum potassium in patients with severe heart failure receiving Aldactone. Avoid using other potassium-sparing diuretics. Avoid using oral potassium supplements in patients with serum potassium > 3.5 mEq/L. RALES excluded patients with a serum creatinine > 2.5 mg/dL or a recent increase in serum creatinine > 25%. The recommended monitoring for potassium and creatinine is one week after initiation or increase in dose of Aldactone, monthly for the first 3 months, then quarterly for a year, and then every 6 months. Discontinue or interrupt treatment for serum potassium > 5 mEq/L or for serum creatinine > 4 mg/dL. (See Clinical Studies, Severe heart failure, and DOSAGE AND ADMINISTRATION, Severe heart failure.)

Aldactone should be used with caution in patients with impaired hepatic function because minor alterations of fluid and electrolyte balance may precipitate hepatic coma.

Lithium generally should not be given with diuretics (see PRECAUTIONS: DRUG INTERACTIONS).

PRECAUTIONS

General

All patients receiving diuretic therapy should be observed for evidence of fluid or electrolyte imbalance, e.g., hypomagnesemia, hyponatremia, hypochloremic alkalosis, and hyperkalemia.

Serum and urine electrolyte determinations are particularly important when the patient is vomiting excessively or receiving parenteral fluids. Warning signs or symptoms of fluid and electrolyte imbalance, irrespective of cause, include dryness of the mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, and gastrointestinal disturbances such as nausea and vomiting. Hyperkalemia may occur in patients with impaired renal function or excessive potassium intake and can cause cardiac irregularities, which may be fatal. Consequently, no potassium supplement should ordinarily be given with Aldactone.

Concomitant administration of potassium-sparing diuretics and ACE inhibitors or nonsteroidal anti-inflammatory drugs (NSAIDs), e.g., indomethacin, has been associated with severe hyperkalemia.

If hyperkalemia is suspected (warning signs include paresthesia, muscle weakness, fatigue, flaccid paralysis of the extremities, bradycardia and shock), an electrocardiogram (ECG) should be obtained. However, it is important to monitor serum potassium levels because mild hyperkalemia may not be associated with ECG changes.

If hyperkalemia is present, Aldactone should be discontinued immediately. With severe hyperkalemia, the clinical situation dictates the procedures to be employed. These include the intravenous administration of calcium chloride solution, sodium bicarbonate solution and/or the oral or parenteral administration of glucose with a rapid-acting insulin preparation. These are temporary measures to be repeated as required. Cationic exchange resins such as sodium polystyrene sulfonate may be orally or rectally administered. Persistent hyperkalemia may require dialysis.

Reversible hyperchloremic metabolic acidosis, usually in association with hyperkalemia, has been reported to occur in some patients with decompensated hepatic cirrhosis, even in the presence of normal renal function.

Dilutional hyponatremia, manifested by dryness of the mouth, thirst, lethargy, and drowsiness, and confirmed by a low serum sodium level, may be caused or aggravated, especially when Aldactone is administered in combination with other diuretics, and dilutional hyponatremia may occur in edematous patients in hot weather; appropriate therapy is water restriction rather than administration of sodium, except in rare instances when the hyponatremia is life-threatening.

Aldactone therapy may cause a transient elevation of BUN, especially in patients with preexisting renal impairment. Aldactone may cause mild acidosis.

Gynecomastia may develop in association with the use of Aldactone; physicians should be alert to its possible onset. The development of gynecomastia appears to be related to both dosage level and duration of therapy and is normally reversible when Aldactone is discontinued. In rare instances some breast enlargement may persist when Aldactone is discontinued.

Laboratory tests

Periodic determination of serum electrolytes to detect possible electrolyte imbalance should be done at appropriate intervals, particularly in the elderly and those with significant renal or hepatic impairments.

Carcinogenesis, mutagenesis, impairment of fertility

Orally administered Aldactone has been shown to be a tumorigen in dietary administration studies performed in rats, with its proliferative effects manifested on endocrine organs and the liver. In an 18-month study using doses of about 50, 150 and 500 mg/kg/day, there were statistically significant increases in benign adenomas of the thyroid and testes and, in male rats, a dose-related increase in proliferative changes in the liver (including hepatocytomegaly and hyperplastic nodules). In a 24-month study in which the same strain of rat was administered doses of about 10, 30, 100 and 150 mg Aldactone/kg/day, the range of proliferative effects included significant increases in hepatocellular adenomas and testicular interstitial cell tumors in males, and significant increases in thyroid follicular cell adenomas and carcinomas in both sexes. There was also a statistically significant, but not dose-related, increase in benign uterine endometrial stromal polyps in females.

A dose-related (above 20 mg/kg/day) incidence of myelocytic leukemia was observed in rats fed daily doses of potassium canrenoate (a compound chemically similar to Aldactone and whose primary metabolite, canrenone, is also a major product of Aldactone in man) for a period of one year. In two-year studies in the rat, oral administration of potassium canrenoate was associated with myelocytic leukemia and hepatic, thyroid, testicular and mammary tumors.

Neither Aldactone nor potassium canrenoate produced mutagenic effects in tests using bacteria or yeast. In the absence of metabolic activation, neither Aldactone nor potassium canrenoate has been shown to be mutagenic in mammalian tests in vitro. In the presence of metabolic activation, Aldactone has been reported to be negative in some mammalian mutagenicity tests in vitro and inconclusive (but slightly positive) for mutagenicity in other mammalian tests in vitro. In the presence of metabolic activation, potassium canrenoate has been reported to test positive for mutagenicity in some mammalian tests in vitro, inconclusive in others, and negative in still others.

In a three-litter reproduction study in which female rats received dietary doses of 15 and 50 mg Aldactone/kg/day, there were no effects on mating and fertility, but there was a small increase in incidence of stillborn pups at 50 mg/kg/day. When injected into female rats (100 mg/kg/day for 7 days, i.p.), Aldactone was found to increase the length of the estrous cycle by prolonging diestrus during treatment and inducing constant diestrus during a two-week post-treatment observation period. These effects were associated with retarded ovarian follicle development and a reduction in circulating estrogen levels, which would be expected to impair mating, fertility and fecundity. Aldactone (100 mg/kg/day), administered i.p. to female mice during a two-week cohabitation period with untreated males, decreased the number of mated mice that conceived (effect shown to be caused by an inhibition of ovulation) and decreased the number of implanted embryos in those that became pregnant (effect shown to be caused by an inhibition of implantation), and at 200 mg/kg, also increased the latency period to mating.

Pregnancy

Teratogenic effects

Pregnancy Category C. Teratology studies with Aldactone have been carried out in mice and rabbits at doses of up to 20 mg/kg/day. On a body surface area basis, this dose in the mouse is substantially below the maximum recommended human dose and, in the rabbit, approximates the maximum recommended human dose. No teratogenic or other embryotoxic effects were observed in mice, but the 20 mg/kg dose caused an increased rate of resorption and a lower number of live fetuses in rabbits. Because of its anti-androgenic activity and the requirement of testosterone for male morphogenesis, Aldactone may have the potential for adversely affecting sex differentiation of the male during embryogenesis. When administered to rats at 200 mg/kg/day between gestation days 13 and 21 (late embryogenesis and fetal development), feminization of male fetuses was observed. Offspring exposed during late pregnancy to 50 and 100 mg/kg/day doses of Aldactone exhibited changes in the reproductive tract including dose-dependent decreases in weights of the ventral prostate and seminal vesicle in males, ovaries and uteri that were enlarged in females, and other indications of endocrine dysfunction, that persisted into adulthood. There are no adequate and well-controlled studies with Aldactone in pregnant women. Aldactone has known endocrine effects in animals including progestational and antiandrogenic effects. The antiandrogenic effects can result in apparent estrogenic side effects in humans, such as gynecomastia. Therefore, the use of Aldactone in pregnant women requires that the anticipated benefit be weighed against the possible hazards to the fetus.

Nursing mothers

Canrenone, a major (and active) metabolite of Aldactone, appears in human breast milk. Because Aldactone has been found to be tumorigenic in rats, a decision should be made whether to discontinue the drug, taking into account the importance of the drug to the mother. If use of the drug is deemed essential, an alternative method of infant feeding should be instituted.

Pediatric use

Safety and effectiveness in pediatric patients have not been established.

Last reviewed on RxList: 8/19/2009

Aldactone Overdosage & Contraindications

OVERDOSE

The oral LD₅₀ of Aldactone is greater than 1,000 mg/kg in mice, rats, and rabbits.

Acute overdosage of Aldactone may be manifested by drowsiness, mental confusion, maculopapular or erythematous rash, nausea, vomiting, dizziness, or diarrhea. Rarely, instances of hyponatremia, hyperkalemia, or hepatic coma may occur in patients with severe liver disease, but these are unlikely due to acute overdosage. Hyperkalemia may occur, especially in patients with impaired renal function.

Treatment: Induce vomiting or evacuate the stomach by lavage. There is no specific antidote. Treatment is supportive to maintain hydration, electrolyte balance, and vital functions.

Patients who have renal impairment may develop spironolactone-induced hyperkalemia. In such cases, Aldactone should be discontinued immediately. With severe hyperkalemia, the clinical situation dictates the procedures to be employed. These include the intravenous administration of calcium chloride solution, sodium bicarbonate solution and/or the oral or parenteral administration of glucose with a rapid-acting insulin preparation. These are temporary measures to be repeated as required. Cationic exchange resins such as sodium polystyrene sulfonate may be orally or rectally administered. Persistent hyperkalemia may require dialysis.

CONTRAINDICATIONS

Aldactone is contraindicated for patients with anuria, acute renal insufficiency, significant impairment of renal excretory function, or hyperkalemia.

Last reviewed on RxList: 8/19/2009

Aldactone Clinical Pharmacology

CLINICAL PHARMACOLOGY

Mechanism of action

Aldactone (spironolactone) is a specific pharmacologic antagonist of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted renal tubule. Aldactone causes increased amounts of sodium and water to be excreted, while potassium is retained. Aldactone acts both as a diuretic and as an antihypertensive drug by this mechanism. It may be given alone or with other diuretic agents which act more proximally in the renal tubule.

Aldosterone Antagonist Activity

Increased levels of the mineralocorticoid, aldosterone, are present in primary and secondary hyperaldosteronism. Edematous states in which secondary aldosteronism is usually involved include congestive heart failure, hepatic cirrhosis, and the nephrotic syndrome. By competing with aldosterone for receptor sites, Aldactone provides effective therapy for the edema and ascites in those conditions. Aldactone counteracts secondary aldosteronism induced by the volume depletion and associated sodium loss caused by active diuretic therapy.

Aldactone is effective in lowering the systolic and diastolic blood pressure in patients with primary hyperaldosteronism. It is also effective in most cases of essential hypertension, despite the fact that aldosterone secretion may be within normal limits in benign essential hypertension.

Through its action in antagonizing the effect of aldosterone, Aldactone inhibits the exchange of sodium for potassium in the distal renal tubule and helps to prevent potassium loss.

Aldactone has not been demonstrated to elevate serum uric acid, to precipitate gout, or to alter carbohydrate metabolism.

Pharmacokinetics

Aldactone is rapidly and extensively metabolized. Sulfur-containing products are the predominant metabolites and are thought to be primarily responsible, together with Aldactone, for the therapeutic effects of the drug. The following pharmacokinetic data were obtained from 12 healthy volunteers following the administration of 100 mg of spironolactone (Aldactone film-coated tablets) daily for 15 days. On the 15th day, spironolactone was given immediately after a low-fat breakfast and blood was drawn thereafter.

	Accumulation Factor: AUC (0-24 hr, day 15)/AUC (0-24 hr, day 1)	Mean Peak Serum Concentration	Mean (SD) Post-Steady State Half-Life
7-α-(thiomethyl) spirolactone (TMS)	1.25	391 ng/mL at 3.2 hr	13.8 hr (6.4) (terminal)
6-β-hydroxy-7-α-(thiomethyl) spirolactone (HTMS)	1.50	125 ng/mL at 5.1 hr	15.0 hr (4.0) (terminal)
Canrenone (C)	1.41	181 ng/mL at 4.3 hr	16.5 hr (6.3) (terminal)
Spironolactone	1.30	80 ng/mL at 2.6 hr	Approximately 1.4 hr (0.5) (β half-life)

The pharmacological activity of spironolactone metabolites in man is not known. However, in the adrenalectomized rat the antimineralocorticoid activities of the metabolites C, TMS, and HTMS, relative to spironolactone, were 1.10, 1.28, and 0.32, respectively. Relative to spironolactone, their binding affinities to the aldosterone receptors in rat kidney slices were 0.19, 0.86, and 0.06, respectively.

In humans the potencies of TMS and 7-α-thiospirolactone in reversing the effects of the synthetic mineralocorticoid, fludrocortisone, on urinary electrolyte composition were 0.33 and 0.26, respectively, relative to spironolactone. However, since the serum concentrations of these steroids were not determined, their incomplete absorption and/or first-pass metabolism could not be ruled out as a reason for their reduced in vivo activities.

Spironolactone and its metabolites are more than 90% bound to plasma proteins. The metabolites are excreted primarily in the urine and secondarily in bile.

The effect of food on spironolactone absorption (two 100 mg Aldactone tablets) was assessed in a single-dose study of 9 healthy, drug-free volunteers. Food increased the bioavailability of unmetabolized spironolactone by almost 100%. The clinical importance of this finding is not known.

Clinical Studies

Severe heart failure: The Randomized Aldactone Evaluation Study (RALES) was a multinational, double-blind study in patients with an ejection fraction of ≤ 35%, a history of New York Heart

Association (NYHA) class IV heart failure within 6 months, and class III-IV heart failure at the time of randomization. All patients were required to be taking a loop diuretic and, if tolerated, an ACE inhibitor. Patients with a baseline serum creatinine of > 2.5 mg/dL or a recent increase of 25% or with a baseline serum potassium of > 5.0 mEq/L were excluded.

Patients were randomized 1:1 to spironolactone 25 mg orally once daily or matching placebo. Follow-up visits and laboratory measurements (including serum potassium and creatinine) were performed every four weeks for the first 12 weeks, then every 3 months for the first year, and then every 6 months thereafter. Dosing could be withheld for serious hyperkalemia or if the serum creatinine increased to > 4.0 mg/dL. Patients who were intolerant of the initial dosage regimen had their dose decreased to one tablet every other day at one to four weeks. Patients who were tolerant of one tablet daily at 8 weeks may have had their dose increased to two tablets daily at the discretion of the investigator.

RALES enrolled 1,663 patients (3% U.S.) at 195 centers in 15 countries between March 24, 1995, and December 31, 1996. The study population was primarily white (87%, with 7% black, 2% Asian, and 4% other), male (73%), and elderly (median age 67). The median ejection fraction was 0.26. Seventy percent were NYHA class III and 29% class IV. The presumed etiology of heart failure was ischemic in 55%, and non-ischemic in 45%. There was a history of myocardial infarction in 28%, of hypertension in 24%, and of diabetes in 22%. The median baseline serum creatinine was 1.2 mg/dL and the median baseline creatinine clearance was 57 mL/min. The mean daily dose at study end for the patients randomized to spironolactone was 26 mg.

Concomitant medications included a loop diuretic in 100% of patients and an ACE inhibitor in 97%. Other medications used at any time during the study included digoxin (78%), anticoagulants (58%), aspirin (43%), and beta-blockers (15%).

The primary endpoint for RALES was time to all-cause mortality. RALES was terminated early, after a mean follow-up of 24 months, because of significant mortality benefit detected on a planned interim analysis. The survival curves by treatment group are shown in Figure 1.

Figure 1. Survival by Treatment Group in RALES

Spironolactone reduced the risk of death by 30% compared to placebo (p < 0.001; 95% confidence interval 18% to 40%). Spironolactone reduced the risk of cardiac death, primarily sudden death and death from progressive heart failure by 31% compared to placebo (p < 0.001; 95% confidence interval 18% to 42%).

Spironolactone also reduced the risk of hospitalization for cardiac causes (defined as worsening heart failure, angina, ventricular arrhythmias or myocardial infarction) by 30% (p < 0.001 95% confidence interval 18% to 41%). Changes in NYHA class were more favorable with spironolactone: In the spironolactone group, NYHA class at the end of the study improved in 41% of patients and worsened in 38% compared to improved in 33% and worsened in 48% in the placebo group (P < 0.001).

Mortality hazard ratios for some subgroups are shown in Figure 2. The favorable effect of spironolactone on mortality appeared similar for both genders and all age groups except patients younger than 55; there were too few non-whites in RALES to draw any conclusions about differential effects by race. Spironolactone’s benefit appeared greater in patients with low baseline serum potassium levels and less in patients with ejection fractions < 0.2. These subgroup analyses must be interpreted cautiously.

Figure 2. Hazard Ratios of All-Cause Mortality by Subgroup in RALES

Figure 2: The size of each box is proportional to the sample size as well as the event rate. ACEI denotes angiotensin-converting enzyme inhibitor, LVEF denotes left ventricular ejection fraction, Cr Clearance denotes creatinine clearance and Ser Creatinine denotes serum creatinine.

Last reviewed on RxList: 8/20/2009

Aldactone Medication Guide

PATIENT INFORMATION

Patients who receive Aldactone should be advised to avoid potassium supplements and foods containing high levels of potassium, including salt substitutes.

Last reviewed on RxList: 8/19/2009

Aldactone Consumer

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

SPIRONOLACTONE – ORAL

(SPY-row-no-LACK-tone)

COMMON BRAND NAME(S): Aldactone

USES: Spironolactone is used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. It is also used to treat swelling (edema) caused by certain conditions (e.g., congestive heart failure) by removing excess fluid and improving symptoms such as breathing problems.

This medication is also used to treat low potassium levels and conditions in which the body is making too much of a natural chemical (aldosterone).

Spironolactone is known as a “water pill” (potassium-sparing diuretic).

OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This medication has also been used to treat excessive hair growth (hirsutism) in women with polycystic ovary disease.

HOW TO USE: Take this medication by mouth, as directed by your doctor. If stomach upset occurs, take it with food or milk. It is best to take your dose early in the day (before 6 p.m.) to prevent having to get up during the night to urinate. Consult your doctor or pharmacist if you have any questions.

Dosage is based on your medical condition and response to therapy. In children, the dosage is also based on body weight.

Take this medication regularly in order to get the most benefit from it. Remember to use it at the same time(s) each day as directed. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick.

Take this medication exactly as prescribed. Do not increase your dose, take it more often than prescribed, or stop using this medicine without first consulting your doctor. Your condition may become worse when the drug is suddenly stopped.

Inform your doctor if your condition worsens (e.g., if you notice an increase in your routine blood pressure readings).

Aldactone Consumer (continued)

SIDE EFFECTS: Drowsiness, lightheadedness, stomach upset, diarrhea, nausea, vomiting, or headache may occur. To minimize lightheadedness, get up slowly when rising from a seated or lying position. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: dizziness, increased thirst, change in the amount of urine, mental/mood changes, unusual fatigue/weakness, muscle spasms, menstrual period changes, breast enlargement (gynecomastia) in men, sexual function problems.

This medication may lead to high levels of potassium, especially in patients with kidney problems. If not treated, very high potassium levels can be fatal. Tell your doctor immediately if you notice any of the following unlikely but serious side effects: slow/irregular heartbeat, muscle weakness.

Tell your doctor immediately if any of these rare but very serious side effects occur: signs of infection (e.g., fever, persistent sore throat), severe stomach/abdominal pain, persistent nausea/vomiting, vomit that looks like coffee grounds, dark urine, yellowing of the eyes/skin.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US –

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking spironolactone, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: no urine output (anuria), severe kidney disease, high blood potassium (hyperkalemia).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver or kidney problems, untreated mineral imbalance (e.g., low sodium).

Before having surgery, tell your doctor or dentist that you are taking this medication.

This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

This drug breaks down into other products that pass into breast milk. Therefore, breast-feeding while using this medication is not recommended. Consult your doctor before breast-feeding.

Aldactone Consumer (continued)

DRUG INTERACTIONS: Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

This drug should not be used with the following medication because very serious interactions may occur: eplerenone.

If you are currently using the medication listed above, tell your doctor or pharmacist before starting spironolactone.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: corticosteroids (e.g., prednisone), certain hormones (ACTH), digoxin, lithium, mitotane, nonsteroidal anti-inflammatory drugs (NSAIDs such as ibuprofen, indomethacin), other diuretics that increase potassium (e.g., amiloride, triamterene).

Other medications besides this medication which may increase your potassium levels include cyclosporine, tacrolimus, potassium supplements, ACE inhibitors (e.g., captopril, lisinopril) or ARBs (e.g., losartan, candesartan). Follow your doctor's instructions carefully and continue medications for your condition as directed. Limit foods high in potassium such as bananas, tomatoes, potatoes, low-salt milk, and salt substitutes. Consult your doctor or pharmacist for more details, including diet recommendations. It is important to keep all medical and laboratory appointments so your doctor can monitor your potassium levels regularly.

Check the labels on all your medicines (e.g., cough-and-cold products, diet aids, NSAIDs for pain/fever reduction) because they may contain ingredients that could increase your blood pressure or worsen swelling (edema). Some nonprescription medicines that contains aspirin may decrease the effects of spironolactone. Low-dose aspirin, as prescribed by your doctor for specific medical reasons such as heart attack or stroke prevention (usually these dosages are 81-325 milligrams per day) should be continued. Consult your doctor or pharmacist for more details.

This medication can affect the results of certain lab tests (e.g., digoxin or cortisol levels). Make sure laboratory personnel and your doctors know you use this drug.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly.

NOTES: Do not share this medication with others.

Laboratory and/or medical tests (e.g., blood mineral levels, kidney or liver function tests) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

If you are taking this medication for high blood pressure, lifestyle changes such as stress reduction programs, exercise, and dietary changes may increase the effectiveness of this medicine. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.

Have your blood pressure checked regularly while taking this medication. Discuss with your doctor and learn how to monitor your own blood pressure. Inform your doctor of your blood pressure readings.

MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store the US product at room temperature below 77 degrees F (25 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

MEDICAL ALERT: Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854- 1166 (USA) or 1-800-668-1507 (Canada).

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Potassium supplementation

Potassium supplementation, either in the form of medication or as a diet rich in potassium, should not ordinarily be given in association with Aldactone therapy.

Hyperkalemia in patients with severe heart failure

Aldactone should be used with caution in patients with impaired hepatic function because minor alterations of fluid and electrolyte balance may precipitate hepatic coma.

Lithium generally should not be given with diuretics (see PRECAUTIONS: DRUG INTERACTIONS).

PRECAUTIONS

General

All patients receiving diuretic therapy should be observed for evidence of fluid or electrolyte imbalance, e.g., hypomagnesemia, hyponatremia, hypochloremic alkalosis, and hyperkalemia.

Concomitant administration of potassium-sparing diuretics and ACE inhibitors or nonsteroidal anti-inflammatory drugs (NSAIDs), e.g., indomethacin, has been associated with severe hyperkalemia.

Aldactone therapy may cause a transient elevation of BUN, especially in patients with preexisting renal impairment. Aldactone may cause mild acidosis.

Laboratory tests

Carcinogenesis, mutagenesis, impairment of fertility

Pregnancy

Teratogenic effects

Nursing mothers

The oral LD₅₀ of Aldactone is greater than 1,000 mg/kg in mice, rats, and rabbits.

Treatment: Induce vomiting or evacuate the stomach by lavage. There is no specific antidote. Treatment is supportive to maintain hydration, electrolyte balance, and vital functions.

CONTRAINDICATIONS

Aldactone is contraindicated for patients with anuria, acute renal insufficiency, significant impairment of renal excretory function, or hyperkalemia

Mechanism of action

Aldosterone Antagonist Activity

Through its action in antagonizing the effect of aldosterone, Aldactone inhibits the exchange of sodium for potassium in the distal renal tubule and helps to prevent potassium loss.

Aldactone has not been demonstrated to elevate serum uric acid, to precipitate gout, or to alter carbohydrate metabolism.

Pharmacokinetics

	Accumulation Factor: AUC (0-24 hr, day 15)/AUC (0-24 hr, day 1)	Mean Peak Serum Concentration	Mean (SD) Post-Steady State Half-Life
7-α-(thiomethyl) spirolactone (TMS)	1.25	391 ng/mL at 3.2 hr	13.8 hr (6.4) (terminal)
6-β-hydroxy-7-α-(thiomethyl) spirolactone (HTMS)	1.50	125 ng/mL at 5.1 hr	15.0 hr (4.0) (terminal)
Canrenone (C)	1.41	181 ng/mL at 4.3 hr	16.5 hr (6.3) (terminal)
Spironolactone	1.30	80 ng/mL at 2.6 hr	Approximately 1.4 hr (0.5) (β half-life)

Spironolactone and its metabolites are more than 90% bound to plasma proteins. The metabolites are excreted primarily in the urine and secondarily in bile.

Clinical Studies

Severe heart failure: The Randomized Aldactone Evaluation Study (RALES) was a multinational, double-blind study in patients with an ejection fraction of ≤ 35%, a history of New York Heart

Figure 1. Survival by Treatment Group in RALES

Figure 2. Hazard Ratios of All-Cause Mortality by Subgroup in RALES

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

SPIRONOLACTONE – ORAL

(SPY-row-no-LACK-tone)

COMMON BRAND NAME(S): Aldactone

USES: Spironolactone is used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. It is also used to treat swelling (edema) caused by certain conditions (e.g., congestive heart failure) by removing excess fluid and improving symptoms such as breathing problems.

This medication is also used to treat low potassium levels and conditions in which the body is making too much of a natural chemical (aldosterone).

Spironolactone is known as a “water pill” (potassium-sparing diuretic).

OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This medication has also been used to treat excessive hair growth (hirsutism) in women with polycystic ovary disease.

HOW TO USE: Take this medication by mouth, as directed by your doctor. If stomach upset occurs, take it with food or milk. It is best to take your dose early in the day (before 6 p.m.) to prevent having to get up during the night to urinate. Consult your doctor or pharmacist if you have any questions.

Dosage is based on your medical condition and response to therapy. In children, the dosage is also based on body weight.

Inform your doctor if your condition worsens (e.g., if you notice an increase in your routine blood pressure readings).

SIDE EFFECTS: Drowsiness, lightheadedness, stomach upset, diarrhea, nausea, vomiting, or headache may occur. To minimize lightheadedness, get up slowly when rising from a seated or lying position. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US –

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking spironolactone, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver or kidney problems, untreated mineral imbalance (e.g., low sodium).

Before having surgery, tell your doctor or dentist that you are taking this medication.

This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

This drug breaks down into other products that pass into breast milk. Therefore, breast-feeding while using this medication is not recommended. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

This drug should not be used with the following medication because very serious interactions may occur: eplerenone.

If you are currently using the medication listed above, tell your doctor or pharmacist before starting spironolactone.

This medication can affect the results of certain lab tests (e.g., digoxin or cortisol levels). Make sure laboratory personnel and your doctors know you use this drug.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly.

NOTES: Do not share this medication with others.

Have your blood pressure checked regularly while taking this medication. Discuss with your doctor and learn how to monitor your own blood pressure. Inform your doctor of your blood pressure readings.

MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store the US product at room temperature below 77 degrees F (25 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.

Aldactone

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