Taking alpha-adrenergic blockers with nitroglycerin can cause what adverse event?

• A. Hypotension with syncope
• B. Hypertension
• C. Tachycardia
• D. Hyperkalemia

Answer: (A)

Combining alpha-adrenergic blockers with nitroglycerin can lead to an excessive drop in blood pressure because both drugs promote vasodilation: alpha blockers block alpha-1–mediated vasoconstriction, lowering systemic vascular resistance, while nitroglycerin causes venodilation and reduced preload. Together, they amplify each other’s effects on blood pressure, which can result in hypotension and sometimes fainting (syncope). Hypertension is not expected with this combination, tachycardia may occur as a reflex to hypotension but isn’t the primary adverse event, and hyperkalemia is not associated with these medications.