RESUMEN
The effect of Atenolol on the blood pressure were studied in 31 cases of essential hypertension and on the effect of plasma renin activity in 8 cases. There were 8 cases of male with age 49.5(42-70) and 23 cases of female with age 49(35-71) years. 27 cases of 31 cases were untreated hypertensive patients and 4 cases were refractory to hypotensive drugs of diuretics and vasodilators. The Atenolol 50mg once-daily was given to all patients orally for 3 weeks. The blood pressure, heart rate, ECG and symptoms were checked in one week interval. In 8 cases, the plasma renin activity was measured by Dainabot Kit before and after one week medication. The results were as follows: 1. In 27 cases of untreated hypertension, the control blood pressure was 182.9/11.4mmHg in average. The blood pressure decreased in average by 18.3/11mmHg in one week, 23.7/15.9mmHg in two week and 21.5/10.5mmHg in three week. The heart rate also decreased by 7.4/min. in one week, 14.9/min. in two week and 7.8/min. in three week. These data showed considerable reduction of blood pressure and heart rate with 50mg Atenolol once-daily. 2. The basal plasma renin activity after one week medication was reduced by 46% in 8 cases and this data showed considerable reduction regardless control level of basal plasma renin activity. 3. There were considerable blood pressure reduction by adding Atenolol 50mg once-daily to diuretics and vasodilator to which patient's blood pressures were refractory. 4. There was no orthostatic hypotension or serious side effect by Atenolol medication.