Hydrochlorothiazide

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 25 to 100 mg daily as a single or divided dose. , 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 initial dose in adults is 25 mg daily given as a single dose. The dose may be increased to 50 mg daily, given as a single or two divided doses.

Doses above 50 mg are often associated with marked reductions in serum potassium (see also PRECAUTIONS ). Patients usually do not require doses in excess of 50 mg of hydrochlorothiazide daily when used concomitantly with other antihypertensive agents.

5 mg per day in infants up to 2 years of age or 100 mg per day in children 2 to 12 years of age. 5 mg per pound (3 mg/kg) per day in two divided doses may be required (see PRECAUTIONS , Pediatric Use ).

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. ) Skin: Erythema multiforme including Stevens-Johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis, alopecia.

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 Interactions ). Acute Myopia and Secondary Angle-Closure Glaucoma Hydrochlorothiazide, a sulfonamide, can cause an idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma.

Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within hours to weeks of drug initiation. Untreated acute angle-closure glaucoma can lead to permanent vision loss. The primary treatment is to discontinue hydrochlorothiazide as rapidly as possible.

Prompt medical or surgical treatments may need to be considered if the intraocular pressure remains uncontrolled. Risk factors for developing acute angle-closure glaucoma may include a history of sulfonamide or penicillin allergy.

CONTRAINDICATIONS

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