Spironolactone And Hydrochlorothiazide

INDICATIONS AND USAGE 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.

DOSAGE AND ADMINISTRATION 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.

ADVERSE REACTIONS 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.

Pharmacokinetics Spironolactone is rapidly and extensively metabolized. Sulfur-containing products are the predominant metabolites and are thought to be primarily responsible, together with spironolactone, 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 (as 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) spironolactone (TMS) 1.25 391 ng/mL at 3.2 hr 13.8 hr (6.4) (terminal) 6-β-hydroxy-7-α- (thiomethyl) spironolactone (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 spironolactone 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. Hydrochlorothiazide is rapidly absorbed following oral administration. Onset of action of hydrochlorothiazide is observed within one hour and persists for 6 to 12 hours. Hydrochlorothiazide plasma concentrations attain peak levels at one to two hours and decline with a half-life of four to five hours. Hydrochlorothiazide undergoes only slight metabolic alteration and is excreted in urine. It is distributed throughout the extracellular space, with essentially no tissue accumulation except in the kidney.