A COMPARISON OF ONCE-DAILY ATENOLOL AND METOPROLOL USING OFFICE AND AMBULATORY BLOOD-PRESSURE MONITORING

The authors compared the relative safety and efficacy of changing trea tment from once-daily atenolol to metoprolol in patients with essentia l hypertension. A parallel-group randomized clinical trial was conduct ed in two phases: a 4-week baseline single-blind phase using atenolol 50 mg, followed by a 4-week randomized double-blind treatment phase us ing either atenolol 50 mg or metoprolol 100 mg administered once daily at noontime. Patients with well-controlled hypertension already presc ribed 50 mg of atenolol (with or without the addition of a diuretic) f or control of hypertension were selected for participation from the ou tpatient hypertension clinic of the Department of Veterans Affairs Med ical Center, Pittsburgh, Pennsylvania. Seated blood pressure (BP) and pulse were obtained during the baseline phase and during the randomize d treatment phase. Twenty-four-hour ambulatory BP monitoring was perfo rmed once during the baseline phase and once during the randomized tre atment phase, near the end of each 4-week period. There were no within - and between-treatment differences in office systolic and diastolic B P. There was a slight increase in pulse (average = 5.2 beats/minute; P = .02) for those participants treated with metoprolol. For within-tre atment groups, the ambulatory BP data showed no significant difference s in systolic and diastolic BPs, except for an increase in morning dia stolic BP for those randomized to metoprolol (average = 6.2 mm Hg; P = .01). For between-treatment groups, the metoprolol arm had a higher m orning systolic BP (P = .01), a higher morning diastolic BP (P = .03), and a higher nighttime heart rate (P = .01). There were no study with drawals due to adverse events. Once-daily administration of both ateno lol and metoprolol appear to control BP as measured by office and ambu latory monitoring techniques, but atenolol appears to maintain BP cont rol more effectively than metoprolol during the end of the dosing inte rval.