LOSARTAN POTASSIUM LOWERS BLOOD-PRESSURE MEASURED BY AMBULATORY BLOOD-PRESSURE MONITORING

Objectives: To determine the blood pressure lowering effect and safety of losartan potassium 50 mg once or twice daily, or 100 mg once daily, using 24-h ambulatory blood pressure monitoring and conventional trough clinic blood pressure. Design: Multicenter, double-blind, randomized, parallel, placebo-controlled trial. Setting: Nine sites in university hospitals and urban centers in the United States*. Patients: 122 mild to moderate hypertensive adult non-black men and women, 21 years of age and older, who were within 30% of their ideal body weight. Intervention: Qualification required a mean 24-h ambulatory blood pressure measurement of greater than or equal to 85 mmHg and a sitting diastolic blood pressure of 95-115 mmHg. Subjects were then randomized to placebo or losartan potassium in three different dose regimens. Clinic blood pressure evaluations: Trough blood pressure was measured by trained observers using standardized methods, and ambulatory blood pressure measurements were obtained for 26 h using a SpaceLabs Model 90207 monitor. Results: All doses of losartan potassium significantly decreased mean systolic 24-h ambulatory blood pressure (range -9.4 to -14.2 mmHg; P less than or equal to 0.01) and mean diastolic 24-h ambulatory blood pressure (range -5.6 to -9.0 mmHg; P less than or equal to 0.01) compared with placebo. All decreases were significantly different from placebo. The 24-h blood pressure profiles revealed a smooth, sustained antihypertensive effect of losartan potassium at all doses. Similar reductions in blood pressure were observed using trough clinic measurements. There were no significant differences in overall clinical adverse experiences between treatment groups. There were no significant changes in heart rate, body weight, electrocardiograms or mean laboratory measurements. Conclusions: Losartan potassium, the first of a new class of potent and specific AT(1)-selective, non-peptide, angiotensin II antagonists, significantly reduces mean 24-h ambulatory blood pressure and trough clinic sitting blood pressure, and is well tolerated.