Thiazide Thiazide Walter Berry (opera singer) Category="Diuretics"Category="Thiazides"Thiazides are a class of Drug that promote water loss from the body ((diuretics)). They inhibit Na⁺/Cl^- reabsorption from the distal convoluted tubules in the kidneys. Thiazides also cause loss of Potassium and an increase in serum Uric acid. The chemical structure of the original thiazide diuretics contained a thiazide ring system; the term is also used for drugs with a similar action that are not chemically thiazides, such as Chlortalidone.

Thiazides are often used to treat Hypertension. They are the recommended first-line treatment in the US (/guidelines/hypertension/ JNC VII) guidelines and a recommended treatment in the European (/knowledge/guidelines/CVD Prevention in Clinical Practice.htm ESC/ESH) guidelines. They have been shown to prevent hypertension-related Morbidity and mortality although the mechanism is not fully understood. They may cause vasodilation by inhibiting Calcium release induced by Norepinephrine.

Side-effects can include Hypokalemia, increased serum Cholesterol, and impotence. The side effect of hypokalemia has motivated combining thiazides with ACE inhibitors, which also lower blood pressure but cause Hyperkalemia as a side-effect.