Effect of withdrawal of terazosin therapy in patients with hypertension.

The effect of withdrawal of terazosin therapy in patients with mild to moderate hypertension was assessed in two double-blind, placebo-controlled studies. All patients had demonstrated a stable blood pressure response to terazosin prior to withdrawal of the drug. Patients were randomly assigned either to continue treatment with terazosin at a previously established dose that had brought blood pressure under control (dose range: 1 to 40 mg daily) or to receive a matching placebo. At the end of a six- or eight-week withdrawal period, placebo-treated patients experienced mean increases of 7.3 and 12.4 mm Hg in supine diastolic blood pressure (studies M81-020 and M81-028 site 1, respectively). These increases were significantly greater than those observed for patients who continued to receive terazosin. Similar results were observed in other blood pressure variables. Withdrawal of terazosin was accompanied by a significant weight loss (2.8 and 3.6 pounds in studies M81-020 and M81-028, respectively). There were no clinically significant changes in pulse rates, physical examinations, laboratory test results, or electrocardiograms. Headache was the most common adverse experience reported by those who received placebo during the drug withdrawal period. These studies demonstrate that withdrawal of terazosin therapy is associated with an increase in supine diastolic blood pressure, often to hypertensive levels, without signs of a withdrawal syndrome.