HYDROCHLOROTHIAZIDE

Apotheca, Inc.

HYDROCHLOROTHIAZIDE 25MG USP Tablets HYDROCHLOROTHIAZIDE 50MG USP Tablets Rx Only

FULL PRESCRIBING INFORMATION: CONTENTS*

• HYDROCHLOROTHIAZIDE DESCRIPTION
• CLINICAL PHARMACOLOGY
  • Pharmacokinetics and Metabolism
• HYDROCHLOROTHIAZIDE INDICATIONS AND USAGE
• HYDROCHLOROTHIAZIDE CONTRAINDICATIONS
• WARNINGS
• PRECAUTIONS
  • Laboratory Tests
  • Drug Interactions
  • Drug/Laboratory Test Interactions
  • Carcinogenesis, Mutagenesis, Impairment of Fertility
  • Pregnancy
  • Nursing Mothers
  • Pediatric Use
• HYDROCHLOROTHIAZIDE ADVERSE REACTIONS
• OVERDOSAGE
• HYDROCHLOROTHIAZIDE DOSAGE AND ADMINISTRATION
• HOW SUPPLIED
• Storage and Dispensing
• PACKAGE LABEL AND PRINCIPAL DISPLAY PANEL

FULL PRESCRIBING INFORMATION

HYDROCHLOROTHIAZIDE DESCRIPTION

Hydrochlorothiazide is a diuretic and antihypertensive. It is the 3,4-dihydro derivative of chlorothiazide. It is chemically designated as 6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine -7-sulfonamide 1,1-dioxide and has the following structural formula:

CLINICAL PHARMACOLOGY

The mechanism of the antihypertensive effect of thiazides is unknown. Hydrochlorothiazide does not usually affect normal blood pressure.

Hydrochlorothiazide affects the distal renal tubular mechanism of electrolyte reabsorption. At maximal therapeutic dosage all thiazides are approximately equal in their diuretic efficacy.

Hydrochlorothiazide 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

Hydrochlorothiazide is not metabolized but is eliminated rapidly by the kidney. When plasma levels have been followed for at least 24 hours, the plasma half-life has been observed to vary between 5.6 and 14.8 hours. At least 61 percent of the oral dose is eliminated unchanged within 24 hours. Hydrochlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk

HYDROCHLOROTHIAZIDE INDICATIONS AND USAGE

Hydrochlorothiazide tablets are indicated as adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy.

Hydrochlorothiazide tablets have also been found useful in edema due to various forms of renal dysfunction such as nephrotic syndrome, acute glomerulonephritis, and chronic renal failure.

Hydrochlorothiazide tablets are 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.

HYDROCHLOROTHIAZIDE CONTRAINDICATIONS

WARNINGS

Use with caution in severe renal disease. In patients with renal disease, thiazides may precipitate azotemia. Cumulative effects of the drug may develop in patients with impaired renal function.

Thiazides should be used with caution in patients with impaired hepatic function or progressive liver disease, since minor alterations of fluid and electrolyte balance may precipitate hepatic coma.

Thiazides may add to or potentiate the action of other antihypertensive drugs. Sensitivity reactions may occur in patients with or without a history of allergy or bronchial asthma.

The possibility of exacerbation or activation of systemic lupus erythematosus has been reported.

Lithium generally should not be given with diuretics (see PRECAUTIONS, Drug lnteractions).

PRECAUTIONS

All patients receiving diuretic therapy should be observed for evidence of fluid or electrolyte imbalance: namely, hyponatremia, hypochloremic alkalosis, and hypokalemia. Serum and urine electrolyte determinations are particularly important when the patient is vomiting excessively or receiving parenteral fluids. Warning signs or symptoms of fluid and electrolyte imbalance, irrespective of cause, include dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, confusion, seizures, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, and gastrointestinal disturbances such as nausea and vomiting.

Hypokalemia may develop, especially with brisk diuresis, when severe cirrhosis is present or after prolonged therapy.

Interference with adequate oral electrolyte intake will also contribute to hypokalemia. Hypokalemia may cause cardiac arrhythmia and may also sensitize or exaggerate the response of the heart to the toxic effects of digitalis (e.g., increased ventricular irritability). Hypokalemia may be avoided or treated by use of potassium sparing diuretics or potassium supplements such as foods with a high potassium content.

Although any chloride deficit is generally mild and usually does not require specific treatment except under extraordinary circumstances (as in liver disease or renal disease), chloride replacement may be required in the treatment of metabolic alkalosis. Dilutional hyponatremia may occur in edematous patients in hot weather; appropriate therapy is water restriction, rather than administration of salt, except in rare instances when the hyponatremia is life threatening. In actual salt depletion, appropriate replacement is the therapy of choice.

Hyperuricemia may occur or acute gout may be precipitated in certain patients receiving thiazides.

In diabetic patients dosage adjustments of insulin or oral hypoglycemic agents may be required. Hyperglycemia may occur with thiazide diuretics. Thus latent diabetes mellitus may become manifest during thiazide therapy.

The antihypertensive effects of the drug may be enhanced in the post-sympathectomy patient.

If progressive renal impairment becomes evident, consider withholding or discontinuing diuretic therapy.

Thiazides have been shown to increase the urinary excretion of magnesium; this may result in hypomagnesemia.

Thiazides may decrease urinary calcium excretion. Thiazides may cause intermittent and slight elevation of serum calcium in the absence of known disorders of calcium metabolism. Marked hypercalcemia may be evidence of hidden hyperparathyroidism. Thiazides should be discontinued before carrying out tests for parathyroid function. Increases in cholesterol and triglyceride levels may be associated with thiazide diuretic therapy.

Laboratory Tests

Drug Interactions

When given concurrently the following drugs may interact with thiazide diuretics.

Potentiation of orthostatic hypotension may occur.

Dosage adjustment of the antidiabetic drug may be required.

Additive effect or potentiation.

Absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent, respectively.

Intensified electrolyte depletion, particularly hypokalemia.

Possible decreased response to pressor amines but not sufficient to preclude their use.

Possible increased responsiveness to the muscle relaxant.

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 hydrochlorothiazide.

In some patients, the administration of a non-steroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when hydrochlorothiazide and non-steroidal anti-inflammatory agents are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.

Drug/Laboratory Test Interactions

Carcinogenesis, Mutagenesis, Impairment of Fertility

Two-year feeding studies in mice and rats conducted under the auspices of the National Toxicology Program (NTP) uncovered no evidence of a carcinogenic potential of hydrochlorothiazide in female mice (at doses of up to approximately 600 mg/kg/day) or in male and female rats (at doses of up to approximately 100 mg/kg/day). The NTP, however, found equivocal evidence for hepatocarcinogenicity in male mice.

Hydrochlorothiazide was not genotoxic in vitro in the Ames mutagenicity assay of Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537, and TA 1538 and in the Chinese Hamster Ovary (CHO) test for chromosomal aberrations, or in vivo in assays using mouse germinal cell chromosomes, Chinese hamster bone marrow chromosomes, and the Drosophila sex-linked recessive lethal trait gene. Positive test results were obtained only in the in vitro CHO Sister Chromatid Exchange (clastogenicity) and in the Mouse Lymphoma Cell (mutagenicity) assays, using concentrations of hydrochlorothiazide from 43 to 1300 µg/mL, and in the Aspergillus nidulans non-disjunction assay at an unspecified concentration.

Hydrochlorothiazide had no adverse effects on the fertility of mice and rats of either sex in studies wherein these species were exposed, via their diet, to doses of up to 100 and 4 mg/kg, respectively, prior to conception and throughout gestation.

Pregnancy

Studies in which hydrochlorothiazide was orally administered to pregnant mice and rats during their respective periods of major organogenesis at doses up to 3000 and 1000 mg hydrochlorothiazide/kg, respectively, provided no evidence of harm to the fetus.

There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Thiazides cross the placental barrier and appear in cord blood. There is a risk of fetal or neonatal jaundice, thrombocytopenia, and possibly other adverse reactions that have occurred in adults.

Nursing Mothers

Thiazides are excreted in breast milk. Because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue hydrochlorothiazide, taking into account the importance of the drug to the mother

Pediatric Use

There are no well-controlled clinical trials in pediatric patients. Information on dosing in this age group is supported by evidence from empiric use in pediatric patients and published literature regarding the treatment of hypertension in such patients. (See DOSAGE AND ADMINISTRATION, Infants and Children).

HYDROCHLOROTHIAZIDE 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.

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 hydrochlorothiazide is removed by hemodialysis has not been established.

The oral LD₅₀ of hydrochlorothiazide is greater than 10 g/kg in the mouse and rat.

HYDROCHLOROTHIAZIDE DOSAGE AND ADMINISTRATION

Therapy should be individualized according to patient response. Use the smallest dosage necessary to achieve the required response.

HOW SUPPLIED

Hydrochlorothiazide Tablets USP are available as round, light orange, flat-faced beveled edge, bisected tablets, debossed with LCI on one side and 1413 on the other side, containing 25 mg of hydrochlorothiazide USP, packaged as follows:

• NDC 12634-445-91 UD Blister Pack
• NDC 12634-445-85 Bottle of 15
• NDC 12634-445-79 Bottle of 25
• NDC 12634-445-78 Bottle of 28
• NDC 12634-445-71 Bottle of 30
• NDC 12634-445-50 Bottle of 50
• NDC 12634-445-60 Bottle of 60
• NDC 12634-445-90 Bottle of 90

• NDC 12634-471-91 UD Blister Pack
• NDC 12634-471-85 Bottle of 15
• NDC 12634-471-79 Bottle of 25
• NDC 12634-471-78 Bottle of 28
• NDC 12634-471-71 Bottle of 30
• NDC 12634-471-50 Bottle of 50
• NDC 12634-471-60 Bottle of 60
• NDC 12634-471-90 Bottle of 90

Storage and Dispensing

PHARMACIST: Dispense in a well-closed container as defined in the USP. Use child-resistant closure.

PACKAGE LABEL AND PRINCIPAL DISPLAY PANEL

30 Tablets NDC 12634-471-71
HYDROCHLOROTHIAZIDE
Tablets, USP
Rx Only 50 MG