[The effects of treatment with atenolol and benazapril on 24-hour pressure variability]

One of the functions of the sympathetic nervous system is to produce a short-term increase in blood pressure. It might be thought, therefore, that antihypertensive drugs which interfere with the functioning of the sympathetic nervous system (e.g. betablockers) would reduce blood pressure variability over 24 h whereas those that act independently of it (e.g. ACE inhibitors) would not. Two groups of 10 hypertensives underwent noninvasive 24-h blood pressure monitoring before and after antihypertensive treatment with a betablocker (atenolol) and an ACE inhibitor (benazepril) respectively. Blood pressure variability was measured by the variability coefficient (standard deviation/mean). Atenolol induced a non-statistically significant decrease in blood pressure variability, whereas benazepril caused a statistically significant increase in systolic blood pressure variability. Therefore, we conclude that the evaluation of ACE-inhibitor therapeutic effect on blood pressure by the "casual" measurement can be misleading in judging the efficacy of such drugs.