Mechanism of action
It is a mild diuretic, chemically related to chlorthalidone; reduces BP at doses which cause little diuresis.Electrolyte disturbances and K+ loss are minimal at antihypertensive doses. It probably has additional vasodilator action exerted through alternation of ionic fluxes across vascular smooth muscle cell particularly Ca 2+ ions. It is well absorbed orally, has an elimination t1/2 of 16 hours.