SPIRONOLACTONE AND HYDROCHLOROTHIAZIDE

Each tablet of spironolactone and hydrochlorothiazide contains 25 mg of spironolactone, USP and 25 mg of hydrochlorothiazide, USP. Spironolactone, an aldosterone antagonist, is 17-Hydroxy-7α-mercapto-3-oxo-17α - pregn-4-ene-21-carboxylic acid γ-lactone acetate and has the following structural formula, molecular formula and molecular weight: Spironolactone is practically insoluble in water, soluble in alcohol, and freely soluble in benzene and in chloroform. Hydrochlorothiazide, a diuretic and antihypertensive, is 6-Chloro-3,4-dihydro-2 H -1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide and has the following structural formula, molecular formula and molecular weight: Hydrochlorothiazide is slightly soluble in water and freely soluble in sodium hydroxide solution. Each tablet for oral administration contains 25 mg of spironolactone and 25 mg of hydrochlorothiazide and the following inactive ingredients: colloidal silicon dioxide, corn starch, D&C Yellow No. 10 Aluminum Lake, FD&C Yellow No. 6 Aluminum Lake, lactose monohydrate, magnesium stearate, L-menthol, microcrystalline cellulose, peppermint oil, sodium lauryl sulfate and sodium starch glycolate (potato). Spironolactone Structural Formula Hydrochlorothiazide Structural Formula

Spironolactone, an ingredient of spironolactone and hydrochlorothiazide tablets, has been shown to be a tumorigen in chronic toxicity studies in rats (see PRECAUTIONS section). Spironolactone and hydrochlorothiazide tablets should be used only in those conditions described below. Unnecessary use of this drug should be avoided. Spironolactone and hydrochlorothiazide tablets are indicated for: 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; The treatment of diuretic-induced hypokalemia in patients with congestive heart failure when other measures are considered inappropriate; The treatment of patients with congestive heart failure taking digitalis when other therapies are considered inadequate or inappropriate. Cirrhosis of the liver accompanied by edema and/or ascites: Aldosterone levels may be exceptionally high in this condition. Spironolactone and hydrochlorothiazide tablets are 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: For patients with essential hypertension in whom other measures are considered inadequate or inappropriate; In hypertensive patients for the treatment of a diuretic-induced hypokalemia when other measures are considered inappropriate; Spironolactone and hydrochlorothiazide tablets are indicated 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. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes, including the classes to which this drug principally belongs. There are no controlled trials demonstrating risk reduction with spironolactone and hydrochlorothiazide tablets. Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than one drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program’s Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits. The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly. Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mmHg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit. Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension (for example, patients with diabetes or hyperlipidemia), and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal. Some antihypertensive drugs have smaller blood pressure effects (as monotherapy) in black patients, and many antihypertensive drugs have additional approved indications and effects (e.g., on angina, heart failure, or diabetic kidney disease). These considerations may guide selection of 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. Spironolactone and hydrochlorothiazide tablets are 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 that is not relieved by rest. In these cases, a short course of diuretics may provide relief and may be appropriate.

Optimal dosage should be established by individual titration of the components. Edema in Adults (Congestive Heart Failure, Hepatic Cirrhosis, or Nephrotic Syndrome) The usual maintenance dose of spironolactone and hydrochlorothiazide tablets is 100 mg each of spironolactone and hydrochlorothiazide daily, administered in a single dose or in divided doses, but may range from 25 mg to 200 mg of each component daily depending on the response to the initial titration. In some instances it may be desirable to administer separate tablets of either spironolactone or hydrochlorothiazide in addition to spironolactone and hydrochlorothiazide tablets in order to provide optimal individual therapy. The onset of diuresis with spironolactone and hydrochlorothiazide tablets occurs promptly and, due to prolonged effect of the spironolactone component, persists for two to three days after spironolactone and hydrochlorothiazide tablets are discontinued. Essential Hypertension Although the dosage will vary depending on the results of titration of the individual ingredients, many patients will be found to have an optimal response to 50 mg to 100 mg each of spironolactone and hydrochlorothiazide daily, given in a single dose or in divided doses. Concurrent potassium supplementation is not recommended when spironolactone and hydrochlorothiazide tablets are used in the long-term management of hypertension or in the treatment of most edematous conditions, since the spironolactone content of spironolactone and hydrochlorothiazide tablets is usually sufficient to minimize loss induced by the hydrochlorothiazide component.

Spironolactone and hydrochlorothiazide tablets are contraindicated in patients with anuria, acute renal insufficiency, significant impairment of renal excretory function, hypercalcemia, hyperkalemia, Addison’s disease, and in patients who are allergic to thiazide diuretics or to other sulfonamide-derived drugs. Spironolactone and hydrochlorothiazide may also be contraindicated in acute or severe hepatic failure.

The following adverse reactions have been reported and, within each category (body system), are listed in order of decreasing severity. Hydrochlorothiazide Body as a whole: Weakness. Cardiovascular: Hypotension including orthostatic hypotension (may be aggravated by alcohol, barbiturates, narcotics, or antihypertensive drugs). Digestive: Pancreatitis, jaundice (intrahepatic cholestatic jaundice), diarrhea, vomiting, sialoadenitis, cramping, constipation, gastric irritation, nausea, anorexia. Eye Disorders: Acute myopia and acute angle-closure glaucoma (see WARNINGS ). Hematologic: Aplastic anemia, agranulocytosis, leukopenia, hemolytic anemia, thrombocytopenia. Hypersensitivity: Anaphylactic reactions, necrotizing angitis (vasculitis and cutaneous vasculitis), respiratory distress including pneumonitis and pulmonary edema, photosensitivity, fever, urticaria, rash, purpura. Metabolic: Electrolyte imbalance (see PRECAUTIONS ), hyperglycemia, glycosuria, hyperuricemia. Musculoskeletal: Muscle spasm. Nervous System/Psychiatric: Vertigo, paresthesias, dizziness, headache, restlessness. Renal: Renal failure, renal dysfunction, interstitial nephritis (see WARNINGS ). Skin: Erythema multiforme, pruritus. Special Senses: Transient blurred vision, xanthopsia. Spironolactone Digestive: Gastric bleeding, ulceration, gastritis, diarrhea and cramping, nausea, vomiting. Reproductive: Gynecomastia (see PRECAUTIONS ), inability to achieve or maintain erection, irregular menses or amenorrhea, postmenopausal bleeding, breast pain. Carcinoma of the breast has been reported in patients taking spironolactone but a cause and effect relationship has not been established. Hematologic: Leukopenia (including agranulocytosis), thrombocytopenia. Hypersensitivity: Fever, urticaria, maculopapular or erythematous cutaneous eruptions, anaphylactic reactions, vasculitis. Metabolism: Hyperkalemia, electrolyte disturbances (see WARNINGS and PRECAUTIONS ) . 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. Post Marketing Experience Non-melanoma Skin Cancer Hydrochlorothiazide is associated with an increased risk of non-melanoma skin cancer. In a study conducted in the Sentinel System, increased risk was predominantly for squamous cell carcinoma (SCC) and in white patients taking large cumulative doses. The increased risk for SCC in the overall population was approximately 1 additional case per 16,000 patients per year, and for white patients taking a cumulative dose of ≥ 50,000 mg the risk increase was approximately 1 additional SCC case for every 6,700 patients per year.

ACE Inhibitors, Angiotensin II Receptor Antagonists, Aldosterone Blockers, Potassium Supplements, Heparin, Low Molecular Weight Heparin, and Other Drugs Known to Cause Hyperkalemia Concomitant administration may lead to severe hyperkalemia. Alcohol, Barbiturates, or Narcotics Potentiation of orthostatic hypotension may occur. Antidiabetic Drugs (e.g., oral agents, insulin) Dosage adjustment of the antidiabetic drug may be required (see PRECAUTIONS ). Corticosteroids, ACTH Intensified electrolyte depletion, particularly hypokalemia, may occur. Pressor Amines (e.g., norepinephrine) Both spironolactone and hydrochlorothiazide reduce 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 spironolactone and hydrochlorothiazide. 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 effects 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 spironolactone and hydrochlorothiazide tablets and NSAIDs are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained. Acetylsalicylic Acid Acetylsalicylic acid may reduce the efficacy of spironolactone. Therefore, when spironolactone and hydrochlorothiazide tablets and acetylsalicylic acid are used concomitantly, spironolactone and hydrochlorothiazide tablets may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained. Digoxin Spironolactone has been shown to increase the half-life of digoxin. This may result in increased serum digoxin levels and subsequent digitalis toxicity. Monitor serum digoxin levels and adjust dose accordingly. Thiazide-induced electrolyte disturbances, i.e., hypokalemia, hypomagnesemia, increase the risk of digoxin toxicity, which may lead to fatal arrhythmic events (see PRECAUTIONS ). Cholestyramine Hyperkalemic metabolic acidosis has been reported in patients given spironolactone concurrently with cholestyramine. Abiraterone Spironolactone binds to the androgen receptor and may increase prostate-specific antigen (PSA) levels in abiraterone-treated prostate cancer patients. Concomitant use of spironolactone is not recommended.