Which medications in the drug class Diuretics, Thiazide are used in the treatment of Hypertension?

Updated: Feb 22, 2019
  • Author: Matthew R Alexander, MD, PhD; Chief Editor: Eric H Yang, MD  more...
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Answer

Diuretics, Thiazide

Thiazide diuretics are used as monotherapy, or they can be administered adjunctively with other antihypertensive agents. Thiazide diuretics inhibit reabsorption of sodium and chloride mostly in the distal tubules. Long-term use of these drugs may result in hyponatremia. [144]

They also increase potassium and bicarbonate excretion and decrease calcium excretion and uric acid retention. Thiazides do not affect normal blood pressure.

Keep in mind that all available loop and thiazide diuretic agents, except ethacrynic acid, possess a sulfonamide group, which has important clinical relevance to those individuals with allergies to sulfonamide agents.

Hydrochlorothiazide (Microzide)

Hydrochlorothiazide is approved for the management of hypertension, alone or in combination with other antihypertensive agents. Unlike potassium-sparing combination diuretic products, hydrochlorothiazide may be used in patients who cannot risk the development of hyperkalemia, including patients taking ACE inhibitors.

Hydrochlorothiazide is available as oral tablets or capsules in doses ranging from 12.5-50 mg. The usual dose is 12.5 mg given alone or in combination with other antihypertensives, with a maximum dose of 50 mg daily. Doses greater than 50 mg are associated with hypokalemia.

Chlorthalidone (Thalitone)

Chlorthalidone is indicated for the management of hypertension either alone or in combination with other antihypertensives. The initial dosage is 25 mg as a single daily dose. Dosage can be titrated to 50 mg if the clinical response is not adequate. If additional control is required, increase the dosage to 100 mg once daily, or a second antihypertensive drug may be added. Doses greater than 100 mg daily usually do not increase effectiveness. Increases in serum uric acid and hypokalemia are dose-related over the 25-100 mg/day range.

Metolazone (Zaroxolyn)

Metolazone is approved for the treatment of hypertension either alone (uncommon) or in combination with other antihypertensives. The initial dosage for hypertension is 2.5 to 5 mg given once daily. Metolazone does not decrease glomerular filtration rate or the renal plasma flow and may be a more effective option for patients with impaired renal function.

Indapamide

Indapamide is chemically not a thiazide, although its structure and function are very similar. The drug enhances the excretion of sodium, chloride, and water by inhibiting the transport of sodium ions across the renal tubule. The hypovolemic action of indapamide is believed to be responsible for the drug's beneficial cardiovascular effects. The half-life of indapamide is approximately 14 hours, so the drug can be taken just once daily. Adverse effects tend to be somewhat milder than with thiazides.


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