Hydrochlorothiazide

Hydrochlorothiazide, sometimes abbreviated HCT, HCTZ, or HZT is a popular diuretic drug of the thiazide class that acts by inhibiting the kidneys' ability to retain water. This reduces the volume of the blood, decreasing blood return to the heart and thus cardiac output and, by other mechanisms, is believed to lower peripheral vascular resistance. Hydrochlorothiazide is sold both as a generic drug and under a large number of brand names, including: Apo-Hydro, Aquazide H, Dichlotride, Hydrodiuril, HydroSaluric, Microzide, Oretic.

Activity

Hydrochlorothiazide belongs to the thiazide class of diuretics, acting on the kidneys to reduce sodium (Na) reabsorption in the distal convoluted tubule. This increases the osmolarity in the lumen, causing less water to be reabsorbed by the collecting ducts. This leads to increased urinary output.

Indications

HCT is often used in the treatment of hypertension, congestive heart failure, symptomatic edema and the prevention of kidney stones. It is effective for nephrogenic diabetes insipidus (paradoxical effect, which decreases urine formation) and is also sometimes used for hypercalciuria and Dent's Disease.

Hypokalemia, an occasional side-effect, can be usually prevented by potassium supplements or combining hydrochlorothiazide with a potassium-sparing diuretic.

Thiazides are also used in the treatment of osteoporosis. Thiazides decrease mineral bone loss by promoting calcium retention in the kidney, and by directly stimulating osteoblast differentiation and bone mineral formation.

Side effects

• Hypokalemia
• Hypomagnesemia
• Hyperuricemia and gout
• High blood sugar
• Hypercalcemia
• Headache
• Nausea/vomiting

External links

• NIH medlineplus druginfo

References