Effects of bunazosin hydrochloride sustained-release formulation on cerebral circulation.

BACKGROUND: We investigated the cerebral blood flow in mild to moderately hypertensive patients with chronic cerebral infarction before and after the administration of bunazosin hydrochloride sustained-release formulation, a selective sympathetic alpha1 receptor blocker.

METHODS: Eleven mild to moderately hypertensive patients (mean age 65.6 years) with chronic cerebral infarction were studied.

INTERVENTIONS: The patients were on enalapril maleate, an angiotensin converting enzyme inhibitor, for one week and then enalapril maleate was switched to bunazosin hydrochloride sustained-release formulation.

MEASURES: The cerebral blood flow study was performed before and 8 weeks after starting the administration of bunazosin hydrochloride sustained-release formulation. Cerebral blood flow was measured using the stable xenon CT method. The picture analysis was performed using AZ-7000. The regional cerebral blood flow was measured by placing the region of interest on the CT images. The regional cerebral blood flows were measured before and 20 minutes after intravenous injection of 17 mg/kg acetazolamide.

RESULTS: The blood flows in the parietal cortex and caudate nucleus 8 weeks after starting the administration of bunazosin hydrochloride sustained-release formulation were significantly greater than those before. The cerebrovascular acetazolamide reactivity in the occipital cortex and caudate nucleus was significantly lower after switching to bunazosin hydrochloride sustained-release formulation than before.

CONCLUSIONS: Considering the reports that angiotensin converting enzyme inhibitors show little influence on cerebral blood flow, the present study suggests that bunazosin hydrochloride sustained-release formulation may show a good influence on cerebral blood flow in mild to moderately hypertensive patients with chronic cerebral infarction.