Chlorothiazide

Description

DESCRIPTION DIURIL ® (chlorothiazide) is a diuretic and antihypertensive. It is 6-chloro-2 H -1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Its empirical formula is C 7 H 6 CIN 3 O 4 S 2 and its structural formula is: 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 0.4%, with methylparaben 0.1%, propylparaben 0.02%, and benzoic acid 0.1% added as preservatives. The inactive ingredients are D&C Yellow 10, flavors, glycerin, purified water, sodium saccharin, sucrose and tragacanth. Chemical Structure

What Is Chlorothiazide Used For?

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. Use in Pregnancy - Routine use of diuretics during normal pregnancy 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 toxemia. Edema during pregnancy may arise from pathologic causes or from the physiologic and mechanical consequences of pregnancy. Thiazides are indicated in pregnancy when edema is due to pathologic causes, just as they are in the absence of pregnancy (see PRECAUTIONS, Pregnancy ). Dependent edema in pregnancy, resulting from restriction of venous return by the gravid uterus, is properly treated through elevation of the lower extremities and use of support stockings. Use of diuretics to lower intravascular volume in this instance is illogical and unnecessary. During normal pregnancy there is hypervolemia which is not harmful to the fetus or the mother in the absence of cardiovascular disease. However, it may be associated with edema, rarely generalized edema. If such edema causes discomfort, increased recumbency will often provide relief. Rarely this edema may cause extreme discomfort which is not relieved by rest. In these instances, a short course of diuretic therapy may provide relief and be appropriate.

Dosage and Administration

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 1,000 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 1,000 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 2,000 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 ½ to 1½ teaspoonfuls of the oral suspension daily) in infants up to 2 years of age or 1,000 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 ).

Side Effects (Adverse Reactions)

ADVERSE REACTIONS The following adverse reactions have been reported and, within each category, are listed in order of decreasing severity: 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, sialadenitis, cramping, constipation, gastric irritation, nausea, anorexia. Hematologic: Aplastic anemia, agranulocytosis, leukopenia, hemolytic anemia, thrombocytopenia. Hypersensitivity: Anaphylactic reactions, necrotizing angiitis (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 including Stevens-Johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis, alopecia. Special Senses: Transient blurred vision, xanthopsia. Urogenital: Impotence. Whenever adverse reactions are moderate or severe, thiazide dosage should be reduced or therapy withdrawn. To report SUSPECTED ADVERSE REACTIONS, contact Salix Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Interactions

Drug Interactions When given concurrently the following drugs may interact with thiazide diuretics. Alcohol, Barbiturates, or Narcotics - potentiation of orthostatic hypotension may occur. Antidiabetic Drugs (Oral Agents and Insulin) - dosage adjustment of the antidiabetic drug may be required. Other Antihypertensive Drugs - additive effect or potentiation. Cholestyramine and Colestipol Resins - Both cholestyramine and colestipol resins have the potential of binding thiazide diuretics and reducing diuretic absorption from the gastrointestinal tract. Corticosteroids, ACTH - intensified electrolyte depletion, particularly hypokalemia. Pressor Amines (e.g., Norepinephrine) - possible decreased response to pressor amines but not sufficient to preclude their use. Skeletal Muscle Relaxants, Nondepolarizing (e.g., Tubocurarine) - possible increased responsiveness to the muscle relaxant. Lithium - generally should not be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. Refer to the package insert for lithium preparations before use of such preparations with DIURIL. Non-steroidal Anti-inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 (COX-2) Inhibitors - In some patients, the administration of a non-steroidal anti-inflammatory agent including a selective COX-2 inhibitor can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when DIURIL and non-steroidal anti-inflammatory agents or selective COX-2 inhibitors are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained. In some patients with compromised renal function (e.g., elderly patients or patients who are volume-depleted, including those on diuretic therapy) who are being treated with NSAIDs, including selective COX-2 inhibitors, the co-administration of angiotensin II receptor antagonists or ACE inhibitors may result in a further deterioration of renal function, including possible acute renal failure. These effects are usually reversible. These interactions should be considered in patients taking NSAIDs including selective COX-2 inhibitors concomitantly with diuretics and angiotensin II antagonists or ACE inhibitors. Therefore, the combination should be administered with caution, especially in the elderly.

Contraindications

CONTRAINDICATIONS Anuria. Hypersensitivity to this product or to other sulfonamide-derived drugs.

Pregnancy and Breastfeeding

Pregnancy Teratogenic Effects - Although reproduction studies performed with chlorothiazide doses of 50 mg/kg/day in rabbits, 60 mg/kg/day in rats and 500 mg/kg/day in mice revealed no external abnormalities of the fetus or impairment of growth and survival of the fetus due to chlorothiazide, such studies did not include complete examinations for visceral and skeletal abnormalities. It is not known whether chlorothiazide can cause fetal harm when administered to a pregnant woman; however, thiazides cross the placental barrier and appear in cord blood. DIURIL should be used during pregnancy only if clearly needed (see INDICATIONS AND USAGE ). Nonteratogenic Effects - Chlorothiazide may cause fetal or neonatal jaundice, thrombocytopenia, and possibly other adverse reactions which have occurred in the adult.

Nursing Mothers Because of the potential for serious adverse reactions in nursing infants from DIURIL, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Overdosage

OVERDOSAGE The most common signs and symptoms observed are those caused by electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. If digitalis has also been administered, hypokalemia may accentuate cardiac arrhythmias. In the event of overdosage, symptomatic and supportive measures should be employed. Emesis should be induced or gastric lavage performed. Correct dehydration, electrolyte imbalance, hepatic coma and hypotension by established procedures. If required, give oxygen or artificial respiration for respiratory impairment. The degree to which chlorothiazide sodium is removed by hemodialysis has not been established. The oral LD 50 of chlorothiazide is 8.5 g/kg, greater than 10 g/kg, and greater than 1 g/kg, in the mouse, rat and dog, respectively.

How Supplied

HOW SUPPLIED DIURIL ® (chlorothiazide) Oral Suspension, 250 mg of chlorothiazide per 5 mL, is a yellow, syrupy liquid, and is supplied as follows: NDC 65649-311-12 250 mg per 5 mL 237 mL Storage DIURIL (chlorothiazide) Oral Suspension: Keep container tightly closed. Protect from freezing, –20°C (–4°F) and store at room temperature, 15° to 30°C (59° to 86°F). Distributed by: Salix Pharmaceuticals, a division of Bausch Health US, LLC Bridgewater, NJ 08807 USA DIURIL is a registered trademark of Merck Sharp & Dohme Corp. used under license. © 2021 Salix Pharmaceuticals, Inc. or its affiliates Rev. 11/2021 9768400