What is the treatment for hypertensive crisis caused by MAOI-TCA interaction?

• A. Phentolamine
• B. Labetalol
• C. Nifedipine
• D. Hydralazine

Answer: (A)

The situation involves a surge of catecholamines, especially norepinephrine, at vascular alpha-1 receptors because MAOIs prevent breakdown of monoamines and TCAs increase their release and reuptake interference. The rapid, targeted way to counter this is to block the alpha-adrenergic vasoconstriction directly. Phentolamine is a reversible nonselective alpha-adrenergic blocker given IV, which quickly relaxes arterioles and lowers systemic vascular resistance, reversing the dangerous vasoconstriction and dropping blood pressure promptly. While other agents can lower BP, they don’t address the underlying catecholamine-driven alpha-vasoconstriction as effectively or quickly in this specific interaction. Labetalol offers some alpha and beta blockade but isn’t the first-line choice for this crisis; nifedipine and hydralazine are less specific to the catecholamine surge and can cause other complications in this context.