HYDROCHLOROTHIAZIDE (hye-droe-klor-oh-thye'a-zide) Apo-Hydro , Esidrix, Oretic, HCTZ, Urozide Classifications: electrolytic and water balance agent; diuretic; thiazide; Therapeutic: diuretic Pregnancy Category: B
|
Availability
12.5 mg capsules; 25 mg, 50 mg, 100 mg tablets; 50 mg/5 mL oral solution
Action
Diuretic action is associated with drug interference with absorption of sodium ions across the distal renal tubular segment
of the nephron. This enhances excretion of sodium, chloride, potassium, bicarbonates, and water.
Therapeutic Effect
It has hypotensive action, elevates plasma renin activity.
Uses
Adjunct in treatment of edema associated with CHF, hepatic cirrhosis, renal failure, and in the management of hypertension.
Unlabeled Uses
Nephrogenic diabetes insipidus, hypercalciuria, and treatment of electrolyte disturbances associated with renal tubular
acidosis.
Contraindications
Hypersensitivity to thiazides or other sulfonamides; anuria.
Cautious Use
Bronchial asthma, allergy; hepatic cirrhosis; renal dysfunction; CHF; stroke, CVA; history of gout, SLE; diabetes mellitus;
older adults; pregnancy (category B).
Route & Dosage
Edema Adult: PO 25200 mg/d in 13 divided doses
Hypertension Adult: PO 12.5100 mg/d in 12 divided doses Child: PO 2.2 mg/kg/d in 2 divided doses Neonate (<6 mo): PO 24 mg/kg/d in 2 divided doses
|
Administration
Oral
- Give with food or milk to reduce GI upset.
- Schedule doses to avoid nocturia and interrupted sleep. If given in 2 doses, schedule second dose no later than 3 p.m.
- Store tablets in tightly closed container at 15°30° C (59°86° F) unless otherwise directed.
Adverse Effects (≥1%)
CNS: Mood changes, unusual tiredness or weakness, dizziness, light-headedness, paresthesias.
CV: Irregular heartbeat, weak pulse, orthostatic hypotension.
GI: Dry mouth, increased thirst, nausea, vomiting, anorexia, diarrhea, pancreatitis,
jaundice.
Hematologic: Agranulocytosis, thrombocytopenia,
aplastic anemia, leukopenia.
Metabolic: Hyperglycemia, glycosuria,
hyperuricemia, hypokalemia. Other: Hypersensitivity reactions, photosensitivity, blurred vision, yellow vision (xanthopsia), muscle spasm.
Diagnostic Test Interference
Falsely decreased value in total-urinary estrogen by spectrophotometric assay. See chlorothiazide.
Interactions
Drug: Amphotericin B, corticosteroids increase hypokalemic effects;
sulfonylureas,
insulin may antagonize hypoglycemic effects;
cholestyramine, colestipol decrease
thiazide absorption;
diazoxide intensifies hypoglycemic and hypotensive effects; increased
potassium and
magnesium loss may cause
digoxin toxicity; decreases
lithium excretion and increases toxicity; increases risk of
nsaid-induced
renal failure and may attenuate diuresis.
Pharmacokinetics
Absorption: Incompletely absorbed.
Onset: 2 h.
Peak: 4 h.
Duration: 612 h.
Distribution: Distributed throughout extracellular tissue; concentrates in kidney; crosses placenta; distributed in breast milk.
Metabolism: Does not appear to be metabolized.
Elimination: In urine.
Half-Life: 45120 min.
Nursing Implications
Assessment & Drug Effects
- Monitor for therapeutic effectiveness. Antihypertensive effects may be noted in 34 d; maximal effects may require
34 wk.
- Lab tests: Baseline and periodic determinations of serum electrolytes, blood counts, BUN, blood glucose, uric acid, CO2, are recommended.
- Check BP before initiation of therapy and at regular intervals.
- Monitor closely for hypokalemia; it increases the risk of digoxin toxicity.
- Monitor I&O and check for edema.
- Note: Drug may cause hyperglycemia and loss of glycemic control in diabetics.
- Note: Drug may cause orthostatic hypotension, dizziness.
Patient & Family Education
- Consult physician before using OTC drugs. Many contain large amounts of sodium as well as potassium.
- Monitor weight daily.
- Note: Diabetic patients need to monitor blood glucose closely. This drug causes impaired glucose tolerance.
- Report signs of hypokalemia (see Appendix F) to physician.
- Change positions slowly; avoid hot baths or showers, extended exposure to sunlight, and sitting or standing still for long
periods.
- Note: Photosensitivity reaction may occur 1014 d after initial sun exposure.