section name header

Pronunciation ⬇

hye-droe-klor-oh-THYE-a-zide

Classifications ⬆ ⬇

Therapeutic Classification: antihypertensives, diuretics

Pharmacologic Classification: thiazide diuretics

Indications ⬆ ⬇

BEERS REMS

Action ⬆ ⬇

  • Increases excretion of sodium and water by inhibiting sodium reabsorption in the distal tubule.
  • Promotes excretion of chloride, potassium, hydrogen, magnesium, phosphate, calcium and bicarbonate.
  • May produce arteriolar dilation.
Therapeutic effects:
  • Lowering of BP in hypertensive patients and diuresis with mobilization of edema.

Pharmacokinetics ⬆ ⬇

Absorption: Rapidly absorbed after oral administration.

Distribution: Distributed into extracellular space.

Metabolism/Excretion: Excreted mainly unchanged by the kidneys.

Half-Life: 6–15 hr.

Time/Action Profile ⬆ ⬇

(diuretic effect)

ROUTEONSETPEAKDURATION
PO‡2 hr3–6 hr6–12 hr



‡Onset of antihypertensive effect is 3–4 days and does not become maximal for 7–14 days of dosing.



Contraind./Precautions ⬆ ⬇

Contraindicated in:

Use Cautiously in:

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypotension

Derm: photosensitivity, rash, SKIN CANCER (NONMELANOMA), STEVENS JOHNSON SYNDROME

EENT: acute angle-closure glaucoma, acute myopia

Endo: hyperglycemia

F and E: hypokalemia, dehydration, hypercalcemia, hypochloremic alkalosis, hypomagnesemia, hyponatremia, hypophosphatemia, hypovolemia

GI: anorexia, cramping, hepatitis, nausea, PANCREATITIS, vomiting

Hemat: blood dyscrasias

Metab: hyperuricemia, hypercholesterolemia

MS: muscle cramps

Neuro: dizziness, drowsiness, lethargy, weakness

Interactions ⬆ ⬇

Drug-drug:

Route/Dosage ⬆ ⬇

  • PO (Adults ): 12.5–100 mg/day in 1–2 doses (up to 200 mg/day; not to exceed 50 mg/day for hypertension; doses above 25 mg are associated with greater likelihood of electrolyte abnormalities).
  • PO (Children >6 mo): 2 mg/kg in 2 divided doses (not to exceed 200 mg/day).
  • PO (Children <6 mo): Up to 2–4 mg/kg/day in 2 divided doses (not to exceed 37.5 mg/day).

Availability ⬆ ⬇

(Generic available)
  • Capsules: 12.5 mg
  • Tablets: 12.5 mg; 25 mg; 50 mg
  • In combination with: numerous antihypertensives. See Appendix [not included in this PDA edition].

Assessment ⬆ ⬇

  • Monitor BP, intake, output, and daily weight and assess feet, legs, and sacral area for edema daily.
    • Assess patient, especially if taking digoxin, for anorexia, nausea, vomiting, muscle cramps, paresthesia, and confusion. Notify health care professional if these signs of electrolyte imbalance occur. Patients taking digoxin are at risk of digoxin toxicity because of the potassium-depleting effect of the diuretic.
    • If hypokalemia occurs, consideration may be given to potassium supplementation or decreasing dose of diuretic.
    • Assess patient for allergy to sulfonamides.
    Assess patient for skin rash frequently during therapy. Discontinue diuretic at first sign of rash; may be life-threatening. Stevens-Johnson syndrome may develop. Treat symptomatically; may recur once treatment is stopped.
  • Hypertension: Monitor BP before and periodically during therapy.
    • Monitor frequency of prescription refills to determine compliance.

Lab Test Considerations:

  • Monitor electrolytes (especially potassium), blood glucose, BUN, serum creatinine, and uric acid levels before and periodically during therapy.
    • May cause ↑ serum and urine glucose in diabetic patients.
    • May cause ↑ serum bilirubin, calcium, creatinine, and uric acid, and ↓ serum magnesium, potassium, sodium, and urinary calcium concentrations.
    • May cause ↑ serum cholesterol, low-density lipoprotein, and triglyceride concentrations.

Implementation ⬆ ⬇

  • Do not confuse hydrochlorothiazide with hydroxyzine, hydralazine, or hydroxychloroquine.
  • Administer in the morning to prevent disruption of sleep cycle.
    • Intermittent dose schedule may be used for continued control of edema.
  • PO: May give with food or milk to minimize GI irritation. Tablets may be crushed and mixed with fluid to facilitate swallowing.

Patient/Family Teaching ⬆ ⬇

  • Instruct patient to take this medication at the same time each day. Take missed doses as soon as remembered but not just before next dose is due. Do not double doses.
    • Instruct patient to monitor weight biweekly and notify health care professional of significant changes.
    • Caution patient to change positions slowly to minimize orthostatic hypotension. This may be potentiated by alcohol.
    • Advise patient to use sunscreen and protective clothing to prevent photosensitivity reactions.
    • Advise patient of the need to undergo skin cancer screenings at least yearly during therapy.
    • Instruct patient to discuss dietary potassium requirements with health care professional (see Food Sources for Specific Nutrients).
    • Instruct patient to notify health care professional of medication regimen before treatment or surgery.
    • Advise patient to notify health care professional if signs and symptoms of hyperglycemia (confusion, fatigue, more thirst, hunger, passing a lot of urine, flushing, fast breathing, breath that smells like fruit), fluid and electrolyte problems (mood changes, confusion, muscle pain or weakness, abnormal heartbeat, severe dizziness or passing out, fast heartbeat, more thirst, seizures, loss of strength and energy, lack of appetite, unable to pass urine or change in the amount of urine produced, dry mouth, dry eyes, or nausea or vomiting), allergic reaction (rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat), weight gain, chest pain or shortness of breath, swelling in the arms or legs, bleeding, bruising, skin lump, skin growth, mole changes, rash, or diarrhea occur.
    • May cause fetal or neonatal jaundice and thrombocytopenia. Advise patient to notify health care professional if pregnancy if planned or suspected and to avoid breastfeeding during therapy.
    • Emphasize the importance of routine follow-up exams.
  • Hypertension: Advise patients to continue taking the medication even if feeling better. Medication controls but does not cure hypertension.
    • Encourage patient to comply with additional interventions for hypertension (weight reduction, low-sodium diet, regular exercise, smoking cessation, moderation of alcohol consumption, and stress management).
    • Instruct patient and family in correct technique for monitoring weekly BP.
    • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking other Rx, OTC, or herbal products, especially cough or cold preparations.

Evaluation/Desired Outcomes ⬆ ⬇

  • Decrease in BP.
    • Decrease in edema.

US Brand Names ⬆ ⬇

Microzide

Pill Image

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