The antihypertensive effect of isradipine was studied in 45 patients with 
mild-to-moderate hypertension (mean age 59 years) using casual and ambulatory 
24-h blood pressure measurement. Patients were included into the study according 
to their casual blood pressure. Isradipine was started at a dose of 1.25 mg 
twice daily for 4 weeks, and increased to 2.5 mg twice daily if casual blood 
pressure was not normalized. If necessary, 3 mg of spirapril, a new 
angiotensin-converting enzyme (ACE) inhibitor, (n = 1) or 5 mg of pindolol (n = 
1) was added. The active-treatment period lasted 24 weeks. At the end of the 
therapy, casual blood pressure was significantly decreased (p < 0.001) from 
173/103 to 150/86 mmHg, and mean ambulatory blood pressure, from 146/87 to 
140/83 mmHg (p < 0.05). When patients were divided into three groups according 
to initial whole-day ambulatory blood pressure values (group I: < 140/90 mmHg; 
group II: > or = 140/90 mmHg; group III: > or = 140/<90 mmHg), no effect of 
treatment was detected in group I. However, whole-day blood pressure fell 
significantly (p < 0.001) in group II (155/96 vs 143/88 mmHg) as did systolic 
blood pressure (p < 0.01) in group III (150/83 vs 142/81 mmHg), whereas 
diastolic blood pressure remained unchanged. Thus, ambulatory blood pressure 
measurement may be superior to casual measurement in the decision-making process 
to treat hypertension, avoiding not only the phenomenon of 'white-coat 
hypertension', but also ineffective treatment. This conclusion, however, should 
be confirmed by prospective studies.