Which medication is likely to cause acute rebound hypertensive episodes upon sudden withdrawal?

Clonidine, a centrally acting α2-adrenergic agonist, is known for its potential to cause rebound hypertension if abruptly discontinued. This is due to its mechanism of action, which involves decreasing sympathetic outflow from the central nervous system, thereby lowering blood pressure. When clonidine is suddenly withdrawn, there is an increased release of norepinephrine, leading to heightened sympathetic activity and consequently causing a significant rise in blood pressure, resulting in acute rebound hypertensive episodes.

In contrast, medications such as verapamil, lisinopril, and hydrochlorothiazide do not typically result in rebound hypertension upon withdrawal. Verapamil is a calcium channel blocker, which has a different mechanism of action aimed at reducing heart rate and vascular resistance. Lisinopril, an ACE inhibitor, works to inhibit the conversion of angiotensin I to angiotensin II, thus managing blood pressure without causing rebound effects. Hydrochlorothiazide, a thiazide diuretic, primarily affects fluid balance and electrolyte regulation. Therefore, while withdrawal from each of these medications may require careful management, they do not generate the same risk of rebound hypertensive episodes associated with sudden discontinuation of clonidine.