Ændret natriumbalance, reduktion af ekstracellulært vand og plasmavolumen, ændring i den renale vaskulære modstand såvel som et reduceret respons overfor noradrenalin og angiotensin II.
Possible mechanisms of the antihypertensive action of hydrochlorothiazide could be: the modified sodium balance, the reduction in extracellular water and plasma volume, a change in renal vascular resistance as well as a reduced response to norepinephrine and angiotensin II.