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Clonidine is an imidazoline sympatholytic, acting on both α₂-adrenergic and imidazoline receptors in the brainstem to induce antihypertensive and negative chronotropic effects in the vasculature and heart respectively.

A 69-year-old gentleman with hypertension presented to the emergency department after multiple syncopal episodes over the past 12 months. Electrocardiogram demonstrated sinus bradycardia with a heart rate of 42 beats per minute. It was hypothesized that the antihypertensive agent clonidine was responsible for inducing symptomatic bradycardia. Clonidine was thus gradually tapered and then discontinued over five days restoring normal sinus rhythm rates while avoiding hypertensive rebound related to sympathetic surge. His heart rate and blood pressure remained within normal limits after the …