hydrochlorothiazide, (Hydrodiuril, Ezide, Hydro-Par [discontinued]), Microzide, and many others

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Medical and Pharmacy Editor:

GENERIC NAME: hydrochlorothiazide

BRAND NAMES: Hydrodiuril (discontinued), Ezide (discontinued), Hydro-Par (discontinued), Microzide, and many combinations with other drugs

DRUG CLASS AND MECHANISM: Hydrochlorothiazide is a diuretic (water pill) used for treating high blood pressure (hypertension) and accumulation of fluid (edema). It works by blocking salt and fluid reabsorption from the urine in the kidneys, causing increased urine output (diuresis). Its mechanism of action in lowering high blood pressure is not well understood. The FDA approved hydrochlorothiazide in February 1959.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 12.5, 25, 50 and 100 mg; Capsules: 12.5 mg

STORAGE: Hydrochlorothiazide should be stored at room temperature, 15 C to 30 C (59 F to 86 F), in a tight, light-resistant container.

PRESCRIBED FOR: Hydrochlorothiazide is used to treat excessive fluid accumulation and swelling (edema) of the body caused by heart failure, cirrhosis, chronic kidney failure, corticosteroid medications, and nephrotic syndrome. It also is used alone or in conjunction with other blood pressure lowering medications to treat high blood pressure. Although hydrochlorothiazide is approved for treating edema in cirrhosis of the liver, it is rarely used because of the availability of other diuretics that are more effective. Hydrochlorothiazide can be used to treat calcium-containing kidney stones because it decreases the amount of calcium excreted by the kidneys in the urine and thus decreases the amount of calcium in urine to form stones.

DOSING: Hydrochlorothiazide may be taken with or without food. The usual adult dose for hypertension is 12.5 to 50 mg once daily. The usual adult dose for treating edema is 25-100 mg once daily or in divided doses.

DRUG INTERACTIONS: Hydrochlorothiazide reduces the elimination of lithium (Lithobid, Eskalith) by the kidneys and can lead to lithium toxicity. Nonsteroidal antiinflammatory drugs (NSAIDs), for example, ibuprofen (Motrin), may reduce the blood pressure lowering effects of hydrochlorothiazide. Blood sugar levels can be elevated by hydrochlorothiazide, necessitating adjustment in the doses of medications that are used for treating diabetes. Combining hydrochlorothiazide with corticosteroids may increase the risk for low levels of blood potassium and other electrolytes. Low blood potassium (hypokalemia) can increase the toxicity of digoxin (Lanoxin).

Cholestyramine (Questran, Questran Light) and colestipol (Colestid) bind to hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by 43% to 85%.

PREGNANCY: There are no adequate studies of hydrochlorothiazide in pregnant women. Thiazides may increase the risk of fetal or neonatal jaundice, low platelet levels, and possibly other adverse reactions that have occurred in adults.

Medically Reviewed by a Doctor on 3/27/2013



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