Hydrochlorothiazide (HCTZ)

A to Z Drug Facts

Hydrochlorothiazide (HCTZ)

	Action
	Indications
	Contraindications
	Route/Dosage
	Interactions
	Lab Test Interferences
	Adverse Reactions
	Precautions
Patient Care Considerations
	Administration/Storage
	Assessment/Interventions
	Patient/Family Education

(high-droe-klor-oh-THIGH-uh-zide)

Esidrix, Ezide, Hydro-Par, Hydro-DIURIL, Microzide, Oretic, Apo-Hydro, Novo-Hydrazide, Urozide

Class: Thiazide diuretic

Action Enhances excretion of sodium, chloride, and water by interfering with transport of sodium ions across renal tubular epithelium.

Indications Adjunctive therapy for edema associated with CHF, hepatic cirrhosis, renal dysfunction, and corticosteroid and estrogen therapy; treatment of hypertension. Unlabeled use(s): Prevention of formation and precurrence of calcium nephrolithiasis; therapy for nephrogenic diabetes insipidus.

Contraindications Hypersensitivity to thiazides, related diuretics, or sulfonamide-derived drugs; anuria; renal decompensation.

Route/Dosage

Edema

ADULTS: PO 25 to 100 mg/day. Rarely patients may require 200 mg/day.

Hypertension

ADULTS: PO 25 to 50 mg/day as single dose or 2 divided doses. INFANTS < 6 MO: PO Up to 3.3 mg/kg/day in 2 doses. INFANTS 6 MO TO 2 YR: PO 12.5 to 37.5 mg daily in 2 doses. CHILDREN 2 TO 12 YR: PO 37.5 to 100 mg daily in 2 doses.

Interactions

Bile acid sequestrants: May reduce thiazide absorption; give thiazide ³ 2 hr before resin. Diazoxide: May cause hyperglycemia. Digitalis glycosides: Diuretic-induced hypokalemia and hypomagnesemia may precipitate digitalis-induced arrhythmias. Lithium: May decrease renal excretion of lithium. Loop diuretics: Synergistic effects may result in profound diuresis and serious electrolyte abnormalities. Sulfonylureas, insulin: May decrease hypoglycemic effect of sulfonylureas. May need to increase dosage of sulfonylureas or insulin.

Lab Test Interferences Drug may decrease serum protein-bound iodine levels without signs of thyroid disturbance. May cause diagnostic interference of serum electrolyte levels, blood and urine glucose levels, serum bilirubin levels, and serum uric acid levels. Drug may increase serum magnesium levels in uremic patients. Drug may cause increased concentrations of total serum cholesterol, total triglycerides, and LDL.

Adverse Reactions

CV: Orthostatic hypotension. CNS: Dizziness; lightheadedness; vertigo; headache; paresthesias; weakness; restlessness; insomnia. DERM: Purpura; photosensitivity; rash; urticaria; necrotizing angitis, vasculitis, cutaneous vasculitis; alopecia; exfoliative dermatitis; toxic epidermal necrolysis; erythema multiforme; Stevens-Johnson syndrome. EENT: Blurred vision; xanthopsia (yellow vision). GI: Anorexia; gastric irritation; nausea; vomiting; abdominal pain or cramping; bloating; diarrhea; constipation; pancreatitis; sialadenitis. GU: Impotence; reduced libido; interstitial nephritis. HEMA: Leukopenia; thrombocytopenia; agranulocytosis; aplastic or hypoplastic anemia; hemolytic anemia. HEPA: Jaundice. META: Hyperglycemia; glycosuria; hyperuricemia; electrolyte imbalance. RESP: Respiratory distress; pneumonitis; pulmonary edema. OTHER: Muscle cramp or spasm; fever; anaphylactic reactions.

Precautions

Pregnancy: Category B. Lactation: Excreted in breast milk. Children: Safety and efficacy have not been established in controlled clinical studies. Hepatic impairment: Minor alterations of fluid and electrolyte balance may precipitate hepatic coma; use drug with caution. Hypersensitivity: May occur in patients with or without history of allergy or bronchial asthma; cross-sensitivity with sulfonamides may also occur. Lupus erythematosus: Exacerbation or activation may occur. Postsympathectomy patients: Drug may enhance antihypertensive effects. Renal impairment: Drug may precipitate azotemia; use drug with caution.

PATIENT CARE CONSIDERATIONS

Administration/Storage

If drug is administered as single dose, give in morning.
Administer drug with food or milk to minimize GI irritation.
Store tablets in tightly closed container at room temperature.

Assessment/Interventions

Obtain patient history, including drug history and any known allergies. Note hypersensitivity to thiazides, oral antidiabetics, and sulfonamides.
Weigh patient daily.
Monitor I & O and check for fluid retention.
Monitor BP lying and standing.
Monitor serum potassium, sodium, calcium, magnesium, blood pH, ABGs, uric acid.
Monitor renal nonprotein nitrogen, BUN, creatinine, and liver (ALT, activated clotting time) function tests.
Monitor blood and urine glucose levels of diabetic patients.
Observe closely for anaphylaxis (eg, shortness of breath, rash, edema) after first dose.
Report rising nonprotein nitrogen, BUN, creatinine or liver enzyme levels to health care provider.
Report muscle weakness, cramps, nausea, blurred vision, dizziness, and potassium levels < 3.5 to health care provider.

OVERDOSAGE: SIGNS & SYMPTOMS
	Orthostatic or general hypotension, tachycardia, shock, weakness, syncope, confusion, dizziness, electrolyte abnormalities, potassium deficiency, vomiting, nausea, lethargy, cramps of calf muscles, thirst, polyuria, anuria

Patient/Family Education

Tell patient to take medication early in day with food or milk.
Instruct patient to monitor weight daily.
Advise patient to avoid exposure to sunlight and to use sunblock or wear protective clothing to avoid photosensitivity reaction.
Instruct diabetic patients to report increased levels of blood glucose to health care provider.
Caution patient to avoid intake of alcoholic beverages.
Instruct patient not to take otc medications without health care provider approval.
Caution patient to rise slowly from lying or sitting position and to lie down if blurred vision or dizziness occurs.
Tell patient to report these symptoms to health care provider: GI disturbances, decrease in urinary output, jaundice, muscle cramps, weakness, nausea, blurred vision or dizziness.
Instruct patient to drink 2 to 3 L of fluids daily unless contraindicated by health care provider.
Advise patient that drug may cause dizziness and blurred vision and to use caution while driving or performing other tasks requiring mental alertness.
Tell patient that therapeutic effect may require 2 to 3 wk.