1) Daily dose was 10-20mg Q.D. for 12 weeks. 2) Mean systolic and diastolic pressure were decreased by 49mmHg(25.9%), and 18mmHg(16.8%) respectively. But there was no significant change in heart rate before and after treatment. 3) Systolic and diastolic blood pressure were stably maintained on the whole day. 4) There were no significant side effects except two cases of aggravated congestive heart failure and hypertension. 5) There were no significant changes on hematologic & biochemical parameters before and after treatment.