NONINVASIVE HEMODYNAMIC-STUDY IN HYPERTENSIVE SUBJECTS AFTER TREATMENT WITH VERAPAMIL SLOW-RELEASE

Aim of this study is to investigate the haemodynamic effects, after th e short and long-term antihypertensive treatment. After a wash-out per iod and a placebo treatment period, 30 hypertensive patients received verapamil SR (slow release, 240 mg o.d.) for 30 days. A significant de crease in systolic and diastolic blood pressure was obtained already 4 h after the first administration of verapamil; it was more evident an d persistent throughout the study. No significant changes of heart rat e or PR interval in ECG were observed. A significant decrease in total vascular resistances, both supine and upright, was evident already 4 h after the drug intake and observed throughout the study. The major e ffect was obtained after one month. No significant changes of cardiac output, cardiac index and stroke volume were recorded. Furthermore, pl asma verapamil levels were measured to confirm that the haemodynamic e ffects are obtained by low drug concentrations. The present study prov ides evidence that the antihypertensive effect of verapamil, whose mec hanism is the reduction of total vascular resistances, is progressive, long acting and achieved by low plasma levels, when slow release form ulation is considered.