Influence of age on the nocturnal fall of blood pressure and its modulation by long-acting calcium antagonists

The clinical significance of the nocturnal fall of blood pressure (BP) was examined. BP was monitored every 5 min for 24 hrs by means of a finger volume oscillometric device. The nocturnal fall was observed in all age groups (young: <40, n=49; adult: 40±lt;60, n=110; old: 60± n=33). The amplitude of nocturnal fall of BP (averaged daytime blood pressure-averaged nighttime blood pressure) in old patients (systolic = 13 ± 11, diastolic = 10 ± 8 mmHg, mean ± SD) was similar to that in the young patients (systolic = 11 ± 8, diastolic = 10 ± 8 mmHg). These 192 subjects were also classified according to mean BP level (MBP) averaged for daytime in the ambulatory blood pressure monitoring records [MBP<85 (mmHg), n=31; 85±MBP<100, n=72; 100±MBP±115, n=49; 115±MBP, n=25]. BP level did not affect the pattern of circadian variation in the normal subjects or in the essential hypertensive patients at WHO stage I or II. The amplitude of the nocturnal fall in systolic BP increased with the increase in BP level, but this was not the case with diastolic BP (mean daytime BP <85 mmHg: systolic = 11 ± 8, diastolic = 8 ± 6 mmHg; 85 ± <100: systolic = 14 ± 8, diastolic = 11 ± 6 mmHg; 1005 d15: systolic = 17 5 9, diastolic = 11 5 8; 1155: systolic 17 2 8, diastolic = 11 2 6 mmHg). Nitrendipine (8.6 ± 5.6 mg, 22.5 ? 11.4 days, n=14) and nisoldipine (9.3 i: 6.2 mg, 21.5 2 11.4 days, n=15) administered once daily in the morning or nifedipine slow release tablet, 20 mg twice daily (n=15, 17.7 ± 5.2 days) induced a significant downward shift in the circadian BP pattern, in other words, the hypotensive effect was also observed during the night when the BP had already been low. Taken together, the information on the nocturnal behavior of BP would be valuable, especially in treating aged patients with essential hypertension with a long-acting antihypertensive drug.