Which condition is most likely to be exacerbated by the use of captopril and a diuretic?

The condition that is most likely to be exacerbated by the use of captopril and a diuretic is orthostatic hypotension. Captopril is an ACE inhibitor that can lower blood pressure by causing blood vessels to relax. When combined with a diuretic, which promotes fluid loss and decreases blood volume, there is a compounded effect on blood pressure reduction.

This concurrent use can significantly increase the risk of orthostatic hypotension, which is characterized by a drop in blood pressure when a person stands up from a sitting or lying position. It can lead to symptoms such as dizziness, lightheadedness, or even fainting.

While the other conditions mentioned may have some relevance in the context of captopril and diuretics, they are not as directly linked to the synergistic effects of these medications on blood pressure regulation. For example, bradycardia is not a typical concern with these medications, and while hyperkalemia can be a concern with captopril, it is more commonly related to potassium-sparing diuretics rather than with thiazide or loop diuretics. Dehydration could occur due to diuretic use but is less directly tied to the combination's impact on blood pressure control.