Acute clonidine withdrawal syndrome following open-heart operation

A patient who underwent cardiopulmonary bypass developed a syndrome of malignant hypertension with agitated delirium, unresponsive to antihypertensive agents, following abrupt withdrawal of clonidine. The literature on this syndrome is reviewed with emphasis placed on prompt recognition. The syndrome can be reversed by resumption of clonidine administration and can be prevented by maintenance of clonidine levels through the perioperative period.