Differential effects of antihypertensive drugs with differing pharmacological properties on the basal ambulatory blood pressure

To investigate how antihypertensive drugs with different pharmacological properties affect ambulatory blood pressure (BP) the JAPANESE Study Group developed a database of clinic and ambulatory BPs before and after antihypertensive treatment of patients throughout Japan. Drugs evaluated were nilvadipine (n = 195; b.i.d, 4-8 mg/day), amlodipine (n = 75; q.d., 2.5-10 mg/day), lisinopril (n = 80; q.d., 10-20 mg/day) and bisoprolol (n = 49; q.d., 5-10 mg/day). The relationship between basal ambulatory BP and the hypotensive effect on ambulatory BP during treatment was examined. All antihypertensive drugs significantly decreased both clinic BP and ambulatory BP. The hypotensive effect determined by measurement of clinic BP was significantly greater than that determined by ambulatory BP. The hypotensive effect was positively correlated with basal ambulatory BP. However, there was a quantitative difference in this characteristic among the drugs. The critical daytime systolic ambulatory BP below which a hypotensive effect was not observed was extrapolated to 128, 127 and 124 mm Hg with nilvadipine, amlodipine and bisoprolol, respectively, while that with lisinopril was 97 mm Hg. The slope of the correlation coefficient between basal daytime ambulatory systolic BP and hypotensive effect with lisinopril was significantly smaller than those with the other drugs (P< 0.0001). The slope for the relationship between night-time ambulatory systolic BP and the hypotensive effect with bisoprolol was the steepest (P< 0.0001). Antihypertensive drugs with different pharmacological properties exhibited differing hypotensive effects on the basal ambulatory BP. Such differences in efficacy of the drugs on the basal ambulatory BP may reflect adverse effects of the drugs and the prognosis of hypertension.