Antihypertensive drug withdrawal syndrome.

After discontinuation of antihypertensive medications, patients may experience symptoms associated with catecholamine excess, with or without a rapid rise in blood pressure; this is referred to as antihypertensive drug withdrawal syndrome. Though most often associated with the discontinuation of clonidine, this syndrome has been reported to follow the withdrawal of many other antihypertensives. Proposed mechanisms for the syndrome, depending on the drug involved, include enhanced activity of (1) the sympathoadrenal system, (2) the renin-angiotensin-aldosterone system, and (3) the thyroid hormones. The typical patient at risk is a younger person with severe hypertension, who has been on multiple drugs in high doses for a long period. Guidelines are provided for minimizing the occurrence of the syndrome and for treating the reaction, should it occur.