COMPARISON OF THE EFFECT OF CARVEDILOL AND ATENOLOL ON CIRCADIAN BLOOD-PRESSURE PROFILE IN PATIENTS WITH ESSENTIAL-HYPERTENSION

We conducted a single-blind, randomised block trial to assess the diur nal blood pressure (BP) profile after therapy with carvedilol, a nonse lective beta-blocker with additional alpha-blockade activity, and aten olol, a cardioselective beta-blocker. 30 patients with mild to moderat e essential hypertension were studied. After a 2-week placebo run-in p eriod, they were randomly assigned to receive either atenolol 50 to 10 0mg once daily (15 patients) or carvedilol 25 to 50mg once daily (15 p atients). 24-hour ambulatory blood pressure (ABP) monitoring was perfo rmed before and after 12 weeks of therapy, using a Kontron Micro AM 56 00 device. The ABP readings were analysed with Fourier series with 4 h armonics. Atenolol and carvedilol significantly decreased office and A BP values versus placebo. Carvedilol: office systolic (SBP)/diastolic blood pressure (DBP) 131 +/- 4/84 +/- 7 vs 160 +/-: 6/101 +/- 5; dayti me SBP/DBP 125 +/- 4/79 +/- 6 vs 138 +/- 5/91 +/- 4; night-time SBP/DB P 115 +/- 5/72 +/- 5 vs 127 +/- 3/80 +/- 4. Atenolol: office SBP/DBP 1 33 +/- 4/88 +/- 3 vs 158 +/- 5/102 +/- 6; daytime SBP/DBP 124 +/- 4/84 +/- 3 vs 143 +/- 3/97 +/- 5; night-time SBP/DBP 117 +/- 3/80 +/- 6 vs 124 +/- 5/88 +/- 4. Heart rate was not significantly reduced by carve dilol. Carvedilol and atenolol showed a similar effect on BP profile; they did not modify the BP circadian rhythm. By contrast, both agents induced a significant decrease in the percentage of dippers (carvedilo l from 73 to 33%, and atenolol from 60 to 40%), thus reducing the noct urnal BP dip. In conclusion, carvedilol and atenolol demonstrated simi lar effects on BP diurnal pattern in patients with essential hypertens ion. Moreover, the smaller reduction in heart rate by carvedilol may p revent severe bradycardia, an important and frequent adverse effect in patients treated with cardioselective beta-blockers.