Vascular effects of isosorbide dinitrate on the common carotid artery in human volunteers

The effects of 20 mg of orally administered isosorbide dinitrate (ISDN, Isocoronal R; CAS 87-33-2) on cerebral hemodynamics were investigated in 14 normal healthy volunteers (average age 32.6 years). The common carotid artery hemodynamics in the right supraclavicular region were measured using an ultrasonic quantitative flow measurement system. 2 h after drug administration, systolic blood pressure (15.5 mmHg, p less than 0.001) and mean blood pressure (7.2 mmHg, p less than 0.02) decreased significantly, but diastolic blood pressure did not change. A decrease in blood flow volume (2.85 ml/s, p less than 0.001) and blood flow velocity (7.00 cm/s, p less than 0.001), and an increase in mean vessel diameter (0.19 mm, p less than 0.05), and volume elasticity (0.68 x 10(5) dyn/cm2, p less than 0.02) were observed with ISDN. Mean vessel diameter increased gradually and reached its maximum at 4 h. However, the other maximal effects of ISDN were exerted at about 2 h. The ultrasonic quantitative flow measurement system was found to be useful in the case of repetitive measurements of the common carotid artery hemodynamics. It has been demonstrated that ISDN (20 mg/subject, p.o.) increases the diameter of the common carotid artery, although it decreases the blood flow in the common carotid artery.