Which medication must be gradually discontinued to avoid rebound hypertension if stopped abruptly?

Which medication must be gradually discontinued to avoid rebound hypertension if stopped abruptly?

• A. Hydralazine
• B. Clonidine
• C. Lisinopril
• D. Amlodipine

Answer: (B)

Clonidine lowers blood pressure by acting on central alpha-2 receptors in the brainstem, which dampens sympathetic nerve activity. When it is suddenly stopped, the “brake” on sympathetic outflow is released abruptly, causing a rapid surge in sympathetic tone. That surge leads to vasoconstriction, increased heart rate, and a sharp rise in blood pressure—potentially a hypertensive crisis. Because of this, clonidine must be tapered gradually over days to weeks to allow the autonomic system to adjust and prevent rebound hypertension. Other antihypertensives don’t produce this classic rebound effect as reliably. For example, stopping a direct-acting vasodilator can cause blood pressure to rise again, but the dangerous rebound spike is most characteristic of clonidine withdrawal. ACE inhibitors and calcium channel blockers may see BP creep back toward baseline if stopped, but they don’t typically cause the same abrupt hypertensive rebound seen with clonidine.

Clonidine lowers blood pressure by acting on central alpha-2 receptors in the brainstem, which dampens sympathetic nerve activity. When it is suddenly stopped, the “brake” on sympathetic outflow is released abruptly, causing a rapid surge in sympathetic tone. That surge leads to vasoconstriction, increased heart rate, and a sharp rise in blood pressure—potentially a hypertensive crisis. Because of this, clonidine must be tapered gradually over days to weeks to allow the autonomic system to adjust and prevent rebound hypertension.

Other antihypertensives don’t produce this classic rebound effect as reliably. For example, stopping a direct-acting vasodilator can cause blood pressure to rise again, but the dangerous rebound spike is most characteristic of clonidine withdrawal. ACE inhibitors and calcium channel blockers may see BP creep back toward baseline if stopped, but they don’t typically cause the same abrupt hypertensive rebound seen with clonidine.