Clonidine-induced bradycardia.

Clonidine is an alpha-adrenergic agent that is used in the treatment of hypertension. Bradycardia has been described as a common effect of clonidine poisoning, but has rarely been described as a side effect at commonly prescribed dosages. Bradyarrhythmias, as a side effect, may have several manifestations and may be symptomatic or asymptomatic. This report proposes mechanisms for clonidine-induced bradycardia, describes persons at risk for this effect, and outlines treatments and preventive measures.