EFFECT OF THE ANTIHYPERTENSIVE DRUGS ON THE AMPLITUDE OF THE 24-H SYSTOLIC AND DIASTOLIC BLOOD PRESSURE RHYTHMS.

S. PEREZ-LLORET; J.E. TOBLLI; D.P. CARDINALI; J. MILEI

Madrir

Congreso; Congreso de la Sociedad Europea de Hipertension; 2006

BACKGROUND: Common antihypertensive drugs are effective for lowering daytime systolic and diastolic blood pressure (SBP and DBP) levels but have minor effects on the nighttime BP means. OBJECTIVE: The effect of the most common antihypertensive drugs on the amplitude of the SBP and DBP 24-h rhythms was studied. METHODS: Two-thousands seven-hundred twenty-nine subjects were evaluated by 24-h Ambulatory Monitoring of BP (Oxford Medilog, Oxford Instruments plc.) at our clinical facilities between 1988 and 2002. Daytime and nighttime periods were defined based on the subjects sleep-wake logbook. Hypertension was defined as diurnal SBP/DBP > 135/85 or if the subject was under antihypertensive treatment. Results were analyzed by ANOVA and Chi-Square test. RESULTS: One-thousand eighty-four subjects (43%) were normotensive. From the hypertensive ones, 64% (984 subjects) were under antihypertensive treatment (ACE blockers 25%; diuretics 27%; Ca-channel blockers 13%; Beta-blockers 10%; other 24%). All drugs lowered diurnal and nocturnal SBP and DBP similarly (9-12% of the BP level of untreated subjects, p<.9). As the reduction in daytime BP was greater than the reduction observed in nighttime BP, 24-h rhythms amplitude were reduced in treated individuals as compared with the untreated ones (SBP: 11±0.2 vs 13±0.3; DBP: 15±0.2 vs 17±0.3, respectively, both p<0.02). No differences in the nighttime BP fall was found between the drugs. CONCLUSION: All treatments were equally effective to reduce daytime and nighttime BP means. As the drug-related nighttime BP reduction was lower then the reduction of the daytime means, the 24-h BP rhythm was lower in treated subjects. Additional treatment may be necessary for restoring normal nighttime BP fall.