Spironolactone

Spironolactone tablets are an aldosterone antagonist indicated for: The treatment of NYHA Class III-IV heart failure and reduced ejection fraction to increase survival, manage edema, and to reduce the need for hospitalization for heart failure ( 1.1 ). Use as an add-on therapy for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions ( 1.2 ). The management of edema in adult patients who are cirrhotic when edema is not responsive to fluid and sodium restrictions and in the setting of nephrotic syndrome when treatment of the underlying disease, restriction of fluid and sodium intake, and the use of other diuretics produce an inadequate response ( 1.3 ). Treatment of primary hyperaldosternism for: ( 1.4 ) Short-term preoperative treatment Long-term maintenance for patients with discrete aldosterone-producing adrenal adenomas who are not candidates for surgery and patients with bilateral micro or macronodular adrenal hyperplasia

Heart Failure: Initiate treatment at 25 mg once daily ( 2.2 ). Hypertension: Initiate treatment at 25 mg to 100 mg daily in either single or divided doses ( 2.3 ). Edema: Initiate therapy in a hospital setting and titrate slowly. The recommended initial daily dose is 100 mg in single or divided doses ( 2. 4). Primary hyperaldosteronism: Initiate treatment at 100 mg to 400 mg in preparation for surgery. In patients unsuitable for surgery use the lowest effective dosage determined for the individual patient ( 2. 5).

Spironolactone Tablets USP, 25 mg are white, film-coated, round tablets, debossed “AN” above “511” on one side and plain on other side. They are available as follows: Boxes of 10x10 UD 100 NDC 63739-544-10 Spironolactone Tablets USP, 50 mg are yellow, film-coated, round tablets, debossed “AN” bisect “514” on one side and plain on other side. They are available as follows: Boxes of 10x10 UD 100 NDC 63739-545-10 Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Dispense in a tight, light-resistant container.

Spironolactone is contraindicated in the patients with: Hyperkalemia Addison’s disease Concomitant use of eplerenone

Spironolactone oral tablets contain 25 mg, 50 mg, or 100 mg of the aldosterone antagonist spironolactone, USP 17hydroxy-7α-mercapto-3-oxo-17α-pregn-4-ene-21-carboxylic acid γ-lactone acetate, which has the following structural formula: Spironolactone, USP is practically insoluble in water, soluble in alcohol, and freely soluble in benzene and in chloroform. Inactive ingredients include calcium sulfate, corn starch, croscarmellose sodium, peppermint flavor, hypromellose, iron oxide, magnesium stearate, microcrystalline cellulose, polydextrose, polyethylene glycol, polyvinyl alcohol, povidone, talc, titanium dioxide, and triacetin. The 50 mg tablet also contains D & C yellow # 10 and FD & C yellow #6.

Agents increasing serum potassium: Concomitant administration can lead to hyperkalemia ( 5.1 , 7.1 ). Lithium: Increased risk of lithium toxicity ( 7.2 ). NSAIDs: May reduce the diuretic, natriuretic and antihypertensive effect of spironolactone ( 7.3 ). Digoxin: Spironolactone can interfere with radioimmunologic assays of digoxin exposure ( 7.4 ). Cholestyramine: Hyperkalemic metabolic acidosis has been reported with concomitant use ( 7.5 ). Acetylsalicylic Acid (ASA): ASA may reduce the efficacy of spironolactone ( 7.6 ).

Patients who receive spironolactone should be advised to avoid potassium supplements and foods containing high levels of potassium, including salt substitutes. This product’s label may have been updated. For current full prescribing information, please visit www.amneal.com. Manufactured by: Amneal Pharmaceuticals LLC Bridgewater, NJ 08807 Distributed by: McKesson Corporation dba SKY Packaging Memphis, TN 38141 21357-2 November 2022

Risk Summary Spironolactone is not present in breast milk; however, limited data from a lactating woman at 17 days postpartum reports the presence of the active metabolite, canrenone, in human breast milk in low amounts that are expected to be clinically inconsequential. In this case, there were no adverse effects reported for the breastfed infant after short term exposure to spironolactone; however, long term effects on a breastfed infant are unknown. There are no data on spironolactone effects on milk production. Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for spironolactone and any potential adverse effects on the breastfed child from spironolactone or from the underlying maternal condition.

Safety and effectiveness in pediatric patients have not been established.

Spironolactone is substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, monitor renal function.

Carcinogenesis Orally administered spironolactone 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 mg/kg/day, 150 mg/kg/day, 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 mg, 30 mg, 100 mg, and 150 mg  spironolactone/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. No increased tumors were seen at doses of 100 mg/kg/day. This dose represents about 5X the human recommended daily dose of 200 mg/day, when based on body surface area. Mutagenesis Neither spironolactone nor potassium canrenoate produced mutagenic effects in tests using bacteria or yeast. In the absence of metabolic activation, neither spironolactone nor potassium canrenoate has been shown to be mutagenic in mammalian tests in vitro. In the presence of metabolic activation, spironolactone 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. Impairment of Fertility In a three-litter reproduction study in which female rats received dietary doses of 15 mg and 50 mg  spironolactone /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.), spironolactone 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. Spironolactone (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.

The following clinically significant adverse reactions are described elsewhere in the labeling: Hyperkalemia [see Warnings and Precautions (5.1) ] Hypotension and Worsening Renal Function [see Warnings and Precautions (5.2) ] Electrolyte and Metabolic Abnormalities [see Warnings and Precautions (5.3) ] Gynecomastia [see Warnings and Precautions (5.4)] Impaired neurological function/coma in patients with hepatic impairment, cirrhosis and ascites [see Use in Specific Populations (8.7) ] The following adverse reactions associated with the use of spironolactone were identified in clinical trials or postmarketing reports. Because these reactions were reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency, reliably, or to establish a causal relationship to drug exposure. Digestive: Gastric bleeding, ulceration, gastritis, diarrhea and cramping, nausea, vomiting. Reproductive: Decreased libido, inability to achieve or maintain erection, irregular menses or amenorrhea, postmenopausal bleeding, breast and nipple pain. Hematologic: Leukopenia (including agranulocytosis), thrombocytopenia. Hypersensitivity: Fever, urticaria, maculopapular or erythematous cutaneous eruptions, anaphylactic reactions, vasculitis. Metabolism: Hyperkalemia, electrolyte disturbances [see Warnings and Precautions (5.1 , 5.3 )] , hyponatremia, hypovolemia. Musculoskeletal: Leg cramps. Nervous system/psychiatric: Lethargy, mental confusion, ataxia, dizziness, headache, drowsiness. Liver/biliary: A very few cases of mixed cholestatic/hepatocellular toxicity, with one reported fatality, have been reported with spironolactone administration. Renal: Renal dysfunction (including renal failure). Skin: Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms (DRESS), alopecia, pruritus.

The oral LD 50 of spironolactone is greater than 1,000 mg/kg in mice, rats, and rabbits. Acute overdosage of spironolactone 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 hyperkalemia. In such cases, discontinue spironolactone.

Risk Summary Based on mechanism of action and findings in animal studies, spironolactone may affect sex differentiation of the male during embryogenesis [see Data] . Rat embryofetal studies report feminization of male fetuses and endocrine dysfunction in females exposed to spironolactone in utero . Limited available data from published case reports and case series did not demonstrate an association of major malformations or other adverse pregnancy outcomes with spironolactone . There are risks to the mother and fetus associated with heart failure, cirrhosis and poorly controlled hypertension during pregnancy [see Clinical Considerations] . Because of the potential risk to the male fetus due to anti-androgenic properties of spironolactone and animal data, avoid spironolactone in pregnant women or advise a pregnant woman of the potential risk to a male fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Pregnant women with congestive heart failure are at increased risk for preterm birth. Stroke volume and heart rate increase during pregnancy, increasing cardiac output, especially during the first trimester. Clinical classification of heart disease may worsen with pregnancy and lead to maternal death. Closely monitor pregnant patients for destabilization of their heart failure. Pregnant women with symptomatic cirrhosis generally have poor outcomes including hepatic failure, variceal hemorrhage, preterm delivery, fetal growth restriction and maternal death. Outcomes are worse with coexisting esophageal varices. Pregnant women with cirrhosis of the liver should be carefully monitored and managed accordingly. Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section, and post-partum hemorrhage). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Data Animal Data Teratology studies with spironolactone 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 antiandrogenic activity and the requirement of testosterone for male morphogenesis, spironolactone 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 mg/kg/day and 100 mg/kg/day doses of spironolactone 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. Spironolactone has known endocrine effects in animals including progestational and antiandrogenic effects.

Spironolactone tablets are indicated for treatment of NYHA Class III-IV heart failure and reduced ejection fraction to increase survival, manage edema, and reduce the need for hospitalization for heart failure. Spironolactone tablets are usually administered in conjunction with other heart failure therapies.

Spironolactone Tablets, USP 25 mg are white, film-coated, round tablets, debossed “AN” above “511” on one side and plain on other side. Spironolactone Tablets, USP 50 mg are yellow, film-coated, round tablets, debossed “AN” bisect “514” on one side and plain on other side.

Spironolactone and its active metabolites are specific pharmacologic antagonists of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted renal tubule. 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 drug by this mechanism. It may be given alone or with other diuretic agents that 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 nephrotic syndrome. By competing with aldosterone for receptor sites, spironolactone provides effective therapy for the edema and ascites in those conditions. Spironolactone counteracts secondary aldosteronism induced by the volume depletion and associated sodium loss caused by active diuretic therapy.

Absorption The mean time to reach peak plasma concentration of spironolactone and the active metabolite, canrenone, in healthy volunteers is 2.6 and 4.3 hours, respectively. Effect of food: Food increased the bioavailability of spironolactone (as measured by AUC) by approximately 95.4%. Patients should establish a routine pattern for taking spironolactone with regard to meals [see Dosage and Administration (2.1) ] . Distribution Spironolactone and its metabolites are more than 90% bound to plasma proteins. Elimination The mean half-life of spironolactone is 1.4 hour. The mean half-life values of its metabolites including canrenone, 7-α-(thiomethyl) spironolactone (TMS), and 6-ß-hydroxy-7-α-(thiomethyl) spironolactone (HTMS) are 16.5, 13.8, and 15 hours, respectively. Metabolism Spironolactone is rapidly and extensively metabolized. Metabolites can be divided into two main categories: those in which sulfur of the parent molecule is removed (e.g., canrenone) and those in which the sulfur is retained (e.g., TMS and HTMS). In humans, the potencies of TMS and 7-α-thiospironolactone in reversing the effects of the synthetic mineralocorticoid, fludrocortisone, on urinary electrolyte composition were approximately a third 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. Excretion : The metabolites are excreted primarily in the urine and secondarily in bile. Specific Populations The impact of age, sex, race/ethnicity, and renal impairment on the pharmacokinetics of spironolactone have not been specifically studied. Patients with Hepatic Impairment: The terminal half-life of spironolactone has been reported to be increased in patients with cirrhotic ascites [see Use in Specific Populations (8.7) ] . Drug Interaction Studies : Drugs and Supplements Increasing Serum Potassium: Concomitant administration of spironolactone with potassium supplementation, salt substitutes containing potassium, a diet rich in potassium, or drugs that can increase potassium, including ACE inhibitors, angiotensin II antagonists, non-steroidal anti-inflammatory drugs (NSAIDs), heparin and low molecular weight heparin, may lead to severe hyperkalemia [see Warnings and Precautions (5.1) and Drug Interactions (7.1) ] . Lithium: Spironolactone reduces the renal clearance of lithium, inducing a high risk of lithium toxicity [see Warnings and Precautions (5.1) and Drug Interactions (7.2) ] . 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 [see Drug Interactions (7.3) ] . Acetylsalicylic acid: A single dose of 600 mg of acetylsalicylic acid inhibited the natriuretic effect of spironolactone, which was hypothesized be due to inhibition of tubular secretion of canrenone, causing decreased effectiveness of spironolactone [see Drug Interactions (7.6) ] .

Pregnancy: Based on animal data, spironolactone may affect sex differentiation of the male during embryogenesis ( 8.1 ).

Hyperkalemia: Monitor serum potassium within one week of initiation and regularly thereafter ( 5.1 ). Hypotension and Worsening Renal Function: Monitor volume status and renal function periodically ( 5.2 ). Electrolyte and Metabolic Abnormalities: Monitor serum electrolytes, uric acid and blood glucose periodically ( 5.3 ). Gynecomastia: Spironolactone can cause gynecomastia ( 5.4 ).

Spironolactone

Spironolactone tablets are an aldosterone antagonist indicated for: The treatment of NYHA Class III-IV heart failure and reduced ejection fraction to increase survival, manage edema, and to reduce the need for hospitalization for heart failure ( 1.1 ). Use as an add-on therapy for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions ( 1.2 ). The management of edema in adult patients who are cirrhotic when edema is not responsive to fluid and sodium restrictions and in the setting of nephrotic syndrome when treatment of the underlying disease, restriction of fluid and sodium intake, and the use of other diuretics produce an inadequate response ( 1.3 ). Treatment of primary hyperaldosternism for: ( 1.4 ) Short-term preoperative treatment Long-term maintenance for patients with discrete aldosterone-producing adrenal adenomas who are not candidates for surgery and patients with bilateral micro or macronodular adrenal hyperplasia

Heart Failure: Initiate treatment at 25 mg once daily ( 2.2 ). Hypertension: Initiate treatment at 25 mg to 100 mg daily in either single or divided doses ( 2.3 ). Edema: Initiate therapy in a hospital setting and titrate slowly. The recommended initial daily dose is 100 mg in single or divided doses ( 2. 4). Primary hyperaldosteronism: Initiate treatment at 100 mg to 400 mg in preparation for surgery. In patients unsuitable for surgery use the lowest effective dosage determined for the individual patient ( 2. 5).

Spironolactone Tablets USP, 25 mg are white, film-coated, round tablets, debossed “AN” above “511” on one side and plain on other side. They are available as follows: Boxes of 10x10 UD 100 NDC 63739-544-10 Spironolactone Tablets USP, 50 mg are yellow, film-coated, round tablets, debossed “AN” bisect “514” on one side and plain on other side. They are available as follows: Boxes of 10x10 UD 100 NDC 63739-545-10 Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Dispense in a tight, light-resistant container.

Spironolactone is contraindicated in the patients with: Hyperkalemia Addison’s disease Concomitant use of eplerenone

Agents increasing serum potassium: Concomitant administration can lead to hyperkalemia ( 5.1 , 7.1 ). Lithium: Increased risk of lithium toxicity ( 7.2 ). NSAIDs: May reduce the diuretic, natriuretic and antihypertensive effect of spironolactone ( 7.3 ). Digoxin: Spironolactone can interfere with radioimmunologic assays of digoxin exposure ( 7.4 ). Cholestyramine: Hyperkalemic metabolic acidosis has been reported with concomitant use ( 7.5 ). Acetylsalicylic Acid (ASA): ASA may reduce the efficacy of spironolactone ( 7.6 ).

Patients who receive spironolactone should be advised to avoid potassium supplements and foods containing high levels of potassium, including salt substitutes. This product’s label may have been updated. For current full prescribing information, please visit www.amneal.com. Manufactured by: Amneal Pharmaceuticals LLC Bridgewater, NJ 08807 Distributed by: McKesson Corporation dba SKY Packaging Memphis, TN 38141 21357-2 November 2022

Risk Summary Spironolactone is not present in breast milk; however, limited data from a lactating woman at 17 days postpartum reports the presence of the active metabolite, canrenone, in human breast milk in low amounts that are expected to be clinically inconsequential. In this case, there were no adverse effects reported for the breastfed infant after short term exposure to spironolactone; however, long term effects on a breastfed infant are unknown. There are no data on spironolactone effects on milk production. Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for spironolactone and any potential adverse effects on the breastfed child from spironolactone or from the underlying maternal condition.

Safety and effectiveness in pediatric patients have not been established.

Spironolactone is substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, monitor renal function.

Carcinogenesis Orally administered spironolactone 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 mg/kg/day, 150 mg/kg/day, 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 mg, 30 mg, 100 mg, and 150 mg  spironolactone/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. No increased tumors were seen at doses of 100 mg/kg/day. This dose represents about 5X the human recommended daily dose of 200 mg/day, when based on body surface area. Mutagenesis Neither spironolactone nor potassium canrenoate produced mutagenic effects in tests using bacteria or yeast. In the absence of metabolic activation, neither spironolactone nor potassium canrenoate has been shown to be mutagenic in mammalian tests in vitro. In the presence of metabolic activation, spironolactone 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. Impairment of Fertility In a three-litter reproduction study in which female rats received dietary doses of 15 mg and 50 mg  spironolactone /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.), spironolactone 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. Spironolactone (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.

The following clinically significant adverse reactions are described elsewhere in the labeling: Hyperkalemia [see Warnings and Precautions (5.1) ] Hypotension and Worsening Renal Function [see Warnings and Precautions (5.2) ] Electrolyte and Metabolic Abnormalities [see Warnings and Precautions (5.3) ] Gynecomastia [see Warnings and Precautions (5.4)] Impaired neurological function/coma in patients with hepatic impairment, cirrhosis and ascites [see Use in Specific Populations (8.7) ] The following adverse reactions associated with the use of spironolactone were identified in clinical trials or postmarketing reports. Because these reactions were reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency, reliably, or to establish a causal relationship to drug exposure. Digestive: Gastric bleeding, ulceration, gastritis, diarrhea and cramping, nausea, vomiting. Reproductive: Decreased libido, inability to achieve or maintain erection, irregular menses or amenorrhea, postmenopausal bleeding, breast and nipple pain. Hematologic: Leukopenia (including agranulocytosis), thrombocytopenia. Hypersensitivity: Fever, urticaria, maculopapular or erythematous cutaneous eruptions, anaphylactic reactions, vasculitis. Metabolism: Hyperkalemia, electrolyte disturbances [see Warnings and Precautions (5.1 , 5.3 )] , hyponatremia, hypovolemia. Musculoskeletal: Leg cramps. Nervous system/psychiatric: Lethargy, mental confusion, ataxia, dizziness, headache, drowsiness. Liver/biliary: A very few cases of mixed cholestatic/hepatocellular toxicity, with one reported fatality, have been reported with spironolactone administration. Renal: Renal dysfunction (including renal failure). Skin: Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms (DRESS), alopecia, pruritus.

The oral LD 50 of spironolactone is greater than 1,000 mg/kg in mice, rats, and rabbits. Acute overdosage of spironolactone 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 hyperkalemia. In such cases, discontinue spironolactone.

Spironolactone oral tablets contain 25 mg, 50 mg, or 100 mg of the aldosterone antagonist spironolactone, USP 17hydroxy-7α-mercapto-3-oxo-17α-pregn-4-ene-21-carboxylic acid γ-lactone acetate, which has the following structural formula: Spironolactone, USP is practically insoluble in water, soluble in alcohol, and freely soluble in benzene and in chloroform. Inactive ingredients include calcium sulfate, corn starch, croscarmellose sodium, peppermint flavor, hypromellose, iron oxide, magnesium stearate, microcrystalline cellulose, polydextrose, polyethylene glycol, polyvinyl alcohol, povidone, talc, titanium dioxide, and triacetin. The 50 mg tablet also contains D & C yellow # 10 and FD & C yellow #6.

Risk Summary Based on mechanism of action and findings in animal studies, spironolactone may affect sex differentiation of the male during embryogenesis [see Data] . Rat embryofetal studies report feminization of male fetuses and endocrine dysfunction in females exposed to spironolactone in utero . Limited available data from published case reports and case series did not demonstrate an association of major malformations or other adverse pregnancy outcomes with spironolactone . There are risks to the mother and fetus associated with heart failure, cirrhosis and poorly controlled hypertension during pregnancy [see Clinical Considerations] . Because of the potential risk to the male fetus due to anti-androgenic properties of spironolactone and animal data, avoid spironolactone in pregnant women or advise a pregnant woman of the potential risk to a male fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Pregnant women with congestive heart failure are at increased risk for preterm birth. Stroke volume and heart rate increase during pregnancy, increasing cardiac output, especially during the first trimester. Clinical classification of heart disease may worsen with pregnancy and lead to maternal death. Closely monitor pregnant patients for destabilization of their heart failure. Pregnant women with symptomatic cirrhosis generally have poor outcomes including hepatic failure, variceal hemorrhage, preterm delivery, fetal growth restriction and maternal death. Outcomes are worse with coexisting esophageal varices. Pregnant women with cirrhosis of the liver should be carefully monitored and managed accordingly. Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section, and post-partum hemorrhage). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Data Animal Data Teratology studies with spironolactone 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 antiandrogenic activity and the requirement of testosterone for male morphogenesis, spironolactone 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 mg/kg/day and 100 mg/kg/day doses of spironolactone 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. Spironolactone has known endocrine effects in animals including progestational and antiandrogenic effects.

Spironolactone tablets are indicated for treatment of NYHA Class III-IV heart failure and reduced ejection fraction to increase survival, manage edema, and reduce the need for hospitalization for heart failure. Spironolactone tablets are usually administered in conjunction with other heart failure therapies.

Spironolactone Tablets, USP 25 mg are white, film-coated, round tablets, debossed “AN” above “511” on one side and plain on other side. Spironolactone Tablets, USP 50 mg are yellow, film-coated, round tablets, debossed “AN” bisect “514” on one side and plain on other side.

Spironolactone and its active metabolites are specific pharmacologic antagonists of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted renal tubule. 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 drug by this mechanism. It may be given alone or with other diuretic agents that 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 nephrotic syndrome. By competing with aldosterone for receptor sites, spironolactone provides effective therapy for the edema and ascites in those conditions. Spironolactone counteracts secondary aldosteronism induced by the volume depletion and associated sodium loss caused by active diuretic therapy.

Absorption The mean time to reach peak plasma concentration of spironolactone and the active metabolite, canrenone, in healthy volunteers is 2.6 and 4.3 hours, respectively. Effect of food: Food increased the bioavailability of spironolactone (as measured by AUC) by approximately 95.4%. Patients should establish a routine pattern for taking spironolactone with regard to meals [see Dosage and Administration (2.1) ] . Distribution Spironolactone and its metabolites are more than 90% bound to plasma proteins. Elimination The mean half-life of spironolactone is 1.4 hour. The mean half-life values of its metabolites including canrenone, 7-α-(thiomethyl) spironolactone (TMS), and 6-ß-hydroxy-7-α-(thiomethyl) spironolactone (HTMS) are 16.5, 13.8, and 15 hours, respectively. Metabolism Spironolactone is rapidly and extensively metabolized. Metabolites can be divided into two main categories: those in which sulfur of the parent molecule is removed (e.g., canrenone) and those in which the sulfur is retained (e.g., TMS and HTMS). In humans, the potencies of TMS and 7-α-thiospironolactone in reversing the effects of the synthetic mineralocorticoid, fludrocortisone, on urinary electrolyte composition were approximately a third 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. Excretion : The metabolites are excreted primarily in the urine and secondarily in bile. Specific Populations The impact of age, sex, race/ethnicity, and renal impairment on the pharmacokinetics of spironolactone have not been specifically studied. Patients with Hepatic Impairment: The terminal half-life of spironolactone has been reported to be increased in patients with cirrhotic ascites [see Use in Specific Populations (8.7) ] . Drug Interaction Studies : Drugs and Supplements Increasing Serum Potassium: Concomitant administration of spironolactone with potassium supplementation, salt substitutes containing potassium, a diet rich in potassium, or drugs that can increase potassium, including ACE inhibitors, angiotensin II antagonists, non-steroidal anti-inflammatory drugs (NSAIDs), heparin and low molecular weight heparin, may lead to severe hyperkalemia [see Warnings and Precautions (5.1) and Drug Interactions (7.1) ] . Lithium: Spironolactone reduces the renal clearance of lithium, inducing a high risk of lithium toxicity [see Warnings and Precautions (5.1) and Drug Interactions (7.2) ] . 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 [see Drug Interactions (7.3) ] . Acetylsalicylic acid: A single dose of 600 mg of acetylsalicylic acid inhibited the natriuretic effect of spironolactone, which was hypothesized be due to inhibition of tubular secretion of canrenone, causing decreased effectiveness of spironolactone [see Drug Interactions (7.6) ] .

Pregnancy: Based on animal data, spironolactone may affect sex differentiation of the male during embryogenesis ( 8.1 ).

Hyperkalemia: Monitor serum potassium within one week of initiation and regularly thereafter ( 5.1 ). Hypotension and Worsening Renal Function: Monitor volume status and renal function periodically ( 5.2 ). Electrolyte and Metabolic Abnormalities: Monitor serum electrolytes, uric acid and blood glucose periodically ( 5.3 ). Gynecomastia: Spironolactone can cause gynecomastia ( 5.4 ).

Spironolactone