DIURIL- chlorothiazide suspension
Salix Pharmaceuticals, Inc
DESCRIPTION
DIURIL* (Chlorothiazide) is a diuretic and antihypertensive. It is 6-chloro-2H -1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Its empirical formula is C7 H6 ClN3 O4 S2
It is a white, or practically white, crystalline powder with a molecular weight of 295.72, which is very slightly soluble in water, but readily soluble in dilute aqueous sodium hydroxide. It is soluble in urine to the extent of about 150 mg per 100 mL at pH 7.
DIURIL Oral Suspension contains 250 mg of chlorothiazide per 5 mL, alcohol 0.5 percent, with methylparaben 0.12 percent, propylparaben 0.02 percent, and benzoic acid 0.1 percent added as preservatives. The inactive ingredients are D&C Yellow 10, flavors, glycerin, purified water, sodium saccharin, sucrose and tragacanth.
CLINICAL PHARMACOLOGY
The mechanism of the antihypertensive effect of thiazides is unknown. DIURIL does not usually affect normal blood pressure.
DIURIL affects the distal renal tubular mechanism of electrolyte reabsorption. At maximal therapeutic dosage all thiazides are approximately equal in their diuretic efficacy.
DIURIL increases excretion of sodium and chloride in approximately equivalent amounts. Natriuresis may be accompanied by some loss of potassium and bicarbonate.
After oral use diuresis begins within 2 hours, peaks in about 4 hours and lasts about 6 to 12 hours.
Pharmacokinetics and Metabolism
DIURIL is not metabolized but is eliminated rapidly by the kidney. The plasma half-life of chlorothiazide is 45-120 minutes. After oral doses, 10-15 percent of the dose is excreted unchanged in the urine. Chlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk.
INDICATIONS AND USAGE
DIURIL is indicated as adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy.
DIURIL has also been found useful in edema due to various forms of renal dysfunction such as nephrotic syndrome, acute glomerulonephritis, and chronic renal failure.
DIURIL is indicated in the management of hypertension either as the sole therapeutic agent or to enhance the effectiveness of other antihypertensive drugs in the more severe forms of hypertension.
DOSAGE AND ADMINISTRATION
Therapy should be individualized according to patient response. Use the smallest dosage necessary to achieve the required response.
Adults
For Edema
The usual adult dosage is 500 mg to 1000 mg (10 mL to 20 mL) once or twice a day. Many patients with edema respond to intermittent therapy, i.e., administration on alternate days or on three to five days each week. With an intermittent schedule, excessive response and the resulting undesirable electrolyte imbalance are less likely to occur.
For Control of Hypertension
The usual adult starting dosage is 500 mg or 1000 mg (10 mL to 20 mL) a day as a single or divided dose. Dosage is increased or decreased according to blood pressure response. Rarely some patients may require up to 2000 mg (40 mL) a day in divided doses.
Infants and Children
For Diuresis and For Control of Hypertension
The usual pediatric dosage is 5 mg to 10 mg per pound (10 mg/kg to 20 mg/kg) per day in single or two divided doses, not to exceed 375 mg per day (2.5 mL to 7.5 mL or � to 1� teaspoonfuls of the oral suspension daily) in infants up to 2 years of age or 1000 mg per day in children 2 to 12 years of age. In infants less than 6 months of age, doses up to 15 mg per pound (30 mg/kg) per day in two divided doses may be required. (See PRECAUTIONS, Pediatric Use.)