Which adverse reaction is associated with Angiotensin II Receptor Blockers (ARBs) such as losartan?

• A. Hyperkalemia
• B. Hypoglycemia
• C. Life-threatening renal dysfunction
• D. Orthostatic hypotension

Answer: (D)

Angiotensin II receptor blockers lower blood pressure by preventing Ang II from binding to AT1 receptors, leading to vasodilation and less aldosterone-mediated fluid retention. This can reduce the body’s ability to maintain blood pressure upon standing, especially if you’re dehydrated or taking other blood-pressure–lowering meds. The resulting drop in cerebral perfusion when moving to an upright position produces lightheadedness or dizziness—orthostatic hypotension. While ARBs can also cause hyperkalemia or renal effects in certain situations, the postural drop in blood pressure is the adverse reaction most directly linked to their vasodilatory action, making orthostatic hypotension the best answer.