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metolazone (me-tole-a-zone)



Therapeutic: antihypertensives, diuretics

Pharmacologic: thiazide-like diuretics


Mild-to-moderate hypertension. Edema associated with CHF or the nephrotic syndrome.


Increases excretion of sodium and water by inhibiting sodium reabsorption in the distal tubule. Promotes excretion of chloride, potassium, magnesium, and bicarbonate. May produce arteriolar dilation. Therapeutic Effects: Lowering of blood pressure in hypertensive patients. Diuresis with subsequent mobilization of edema. Effect may continue in renal impairment.

Adverse Reactions/Side Effects

CNS: drowsiness, lethargy. CV: chest pain, hypotension, palpitations. GI: anorexia, bloating, cramping, drug-induced hepatitis, nausea, vomiting. Derm: photosensitivity, rashes. Endo: hyperglycemia. F and E: hypokalemia, dehydration, hypercalcemia, hypochloremic alkalosis, hypomagnesemia, hyponatremia, hypophosphatemia, hypovolemia. Hemat: blood dyscrasias. Metab: hyperuricemia. MS: muscle cramps. Misc: chills, pancreatitis.


Examination and Evaluation

  • Monitor signs of fluid, electrolyte, or acid-base imbalances, including dizziness, drowsiness, blurred vision, confusion, hypotension, or muscle cramps and weakness. Report excessive or prolonged symptoms to the physician.

  • Assess dizziness and weakness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

  • Assess blood pressure periodically and compare to normal values (See Appendix F) to help document antihypertensive effects. Report low blood pressure (hypotension) or other cardiac symptoms such as chest pain or palpitations.

  • When used to treat edema, help determine drug effects by assessing peripheral edema using girth measurements, volume displacement, and measurement of pitting edema (See Appendix N). Also monitor signs of pulmonary edema such as dyspnea and rales/crackles (See Appendix K). Document whether peripheral and pulmonary symptoms are controlled adequately by diuretic therapy.

  • Monitor signs of hyperglycemia (drowsiness, fruity breath, increased urination, unusual thirst).

    Patients with diabetes mellitus should check blood glucose levels frequently.


  • Implement fall-prevention strategies, especially in older adults or if patient exhibits sedation, dizziness, blurred vision, or other impairments that affect gait and balance (See Appendix E).

  • Use caution during aerobic exercise, especially in hot environments. Increased sweating will cause fluid and electrolyte loss, and may exaggerate diuretic side effects (dizziness, muscle cramps, and so forth).

  • To minimize orthostatic hypotension, patient should move slowly when assuming a more upright position.

  • Causes photosensitivity; use care if administering UV treatments.

Patient/Client-Related Instruction

  • Remind patients to take medication as directed to control hypertension and other cardiac conditions even if they are asymptomatic.

  • Counsel patients about additional interventions to help control blood pressure and cardiac dysfunction, including regular exercise, weight loss, sodium restriction, stress reduction, moderation of alcohol consumption, and smoking cessation.

  • Instruct patient to report signs of thrombocytopenia (bruising, ...

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