ADMINISTRATION OF ANTIHYPERTENSIVE DRUGS FOR THE PREVENTION OF CEREBROVASCULAR DISEASES FROM THE VIEWPOINT OF CIRCADIAN CHANGE IN BLOOD PRESSURE

Abstract

We have pointed out the increased incidence of onset of cerebral infarction in the morning hours and that the abrupt increase in blood viscosity early in the morning is one of the possible factors directly related to the timing of such occurrences. On the other hand, since it is known that blood pressure shows a diurnal pattern similar to that of blood viscosity, its change may be also involved in the initiation of cerebrovascular diseases. Thus, we examined, using a portable sphygmomanometer, circadian variation of blood pressure, and the effect of captopril retard on it, in 6 patients (4 males and 2 females) with mild hypertension with special interest in its early morning change. As a result, in all cases, an increase in blood pressure a couple of hours before awaking early in the morning was observed. Administration of captopril retard just before going to bed, tended to mitigate the increase in blood pressure early in the morning in 5 cases. In one case, however, excessive fall of blood pressure during the night made for a rather abrupt increase in blood pressure early in the morning. From these findings, it is suggested that while administration of antihypertensive drugs just before going to bed is recommended for the prevention of cerebrovascular diseases, its timing must be carefully decided for each patient because the circadian change in blood pressure varies from patient to patient.