Rapid rise in blood pressure after discontinuation of chronic antihypertensive therapy

In a trial performed by the Medical Research Council Working Party of Mild Hypertension, 2765 patients were randomly assigned to bendrofluazide, propranolol, or placebo. Both systolic and diastolic pressures fell more with drug therapy than placebo (phase 1). At six years, patients in the drug therapy groups were reassigned to continued therapy or placebo (phase 2). The fall in both systolic and diastolic pressures was maintained in those on continued therapy, while switching to placebo led, within 9 to 12 months, to a rise in blood pressure to a level similar to the values in patients treated with placebo from the beginning.