Does withdrawal of antihypertensive medication increase the risk of cardiovascular events?

The Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure recommends that attempts to discontinu e antihypertensive drug therapy be considered after blood pressure (BP) has been controlled for 1 year. However, discontinuation of drug therapy could unmask underlying conditions and precipitate clinical cardiovascular event s. The Trial of Nonpharmacologic Interventions in the Elderly (TONE) was a clinical trial of the efficacy of weight loss and/or sodium reduction in co ntrolling BP after withdrawal of drug therapy in patients with a BP<145/85 mm Hg on 1 antihypertensive medication. Of 975 participants, 886 entered th e drug withdrawal phase of the trial and 774 were successfully withdrawn fr om their medications. Thirty-three events (stroke, transient ischemic attac k, myocardial infarction, arrhythmia, congestive heart failure, angina, oth er) occurred between randomization and the onset of drug withdrawal (median time 3.6 months), 57 events occurred either during or after drug withdrawa l (14.0 months), and 36 events occurred after resumption of antihypertensiv e therapy (15.9 months). Event rates per 100 person-years were 5.5, 5.5, an d 6.8 for the 3 time periods (p = 0.84) in the nonoverweight group and 7.2, 5.2, and 5.6 (p = 0.08) in the overweight group. The study shows that anti hypertensive medication can be safely withdrawn in older persons without cl inical evidence of cardiovascular disease who do not have diastolic pressur e greater than or equal to 150/90 mm Hg at withdrawal, providing that good BP control can be maintained with nonpharmacologic therapy. (C) 1998 by Exc erpta Medica, Inc.