Final answer:
A client's understanding of hydrochlorothiazide is evident if they can articulate that it will increase their urination due to its effect on sodium and chloride ion reabsorption, leading to reduced blood pressure.
Step-by-step explanation:
A client demonstrating understanding of the teaching on hydrochlorothiazide might make a statement like, "I will need to monitor for increased urination as this medication will decrease my body's reabsorption of sodium and chloride, which can lead to a lower blood pressure." This statement shows the client's grasp on the mechanism by which hydrochlorothiazide, a thiazide diuretic, functions to control hypertension. Unlike loop diuretics, which act on the loop of Henle, hydrochlorothiazide inhibits the Na/Cl symporter in the distal convoluted tubule (DCT), leading to an increased excretion of these ions, followed by water, thus increasing urine volume and reducing overall blood volume. As a side effect, the loss of these ions in urine can result in increased frequency of urination, which the client identifies.