Comparison of the antihypertensive efficiency of nitrendipine, metoprolol, mepindolol and enalapril using ambulatory 24-hour blood pressure monitoring

Comparative Effects of a New Cardioselective Beta-Blocker Nebivolol and Nifedipine Sustained-Release on 24-Hour Ambulatory Blood Pressure and Plasma Lipoproteins

This double-blind, parallel-group study compared the effects of nebivolol, a novel cardioselective beta-blocker, with those of nifedipine sustained-release on 24-hour ambulatory blood pressure and plasma lipoprotein levels. After a washout period of 8 weeks, 51 patients with mild to moderate essential hypertension were randomized to double-blind treatment with either nebivolol 5 mg once a day (n = 26) or nifedipine sustained-release 20 mg bid (n = 25) over a period of 12 weeks. Both treatments produced similar and significant (P = .0001) reduction in office blood pressure as well as in 24-hour, work, awake, and sleep ambulatory blood pressure. The clinical response (diastolic blood pressure less than 90 mmHg or decreased by greater than or equal to 10 mmHg) rate was 69% for nebivolol and 59% for nifedipine, respectively. Moreover, the nebivolol and nifedipine treatment-induced decreases in mean 24-hour ambulatory blood pressure were similar to the decreases in clinic blood pressure. Furthermore, the percentages of "blood pressure loads" (awake greater than 140/90 mmHg and asleep greater than 120/80 mmHg) were lowered significantly (P = .0001), from 60% to 29% with nebivolol and from 60% to 39% with nifedipine. Mean ambulatory heart rate was reduced (P = .0001) from 79 +/- 7 to 68 +/- 7 beats/minute during nebivolol therapy and from 80 +/- 9 to 79 +/- 7 (not significant) with nifedipine. Total plasma cholesterol and low-density lipoprotein levels decreased significantly (P less than .05) by 5 and 8%, respectively, after nebivolol treatment, and each decreased by 3% after nifedipine treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct selective blockade of the vascular angiotensin II receptors in therapy for hypertension and severe congestive heart failure

ACEIs are widely prescribed antihypertensives and have become the mainstay of therapy for severe CHF. Nevertheless, a focused AII-receptor blockade has compelling intellectual appeal and substantial clinical advantages over the ACEIs (no disruption of the prostaglandin and bradykinin biosystems). Identification and careful characterization of the AII receptors and the recent discovery of their antagonists has led to the extensive clinical investigation of selective AII-receptor blockers in both hypertension and severe CHF. Studies with the first orally active AII-receptor blocker, losartan, have demonstrated safe and effective control of elevated blood pressure and improvement of the abnormal hemodynamics typical of pronounced CHF. Several other oral AII-receptor blockers are currently being evaluated, and early results with these agents are encouraging.

Antihypertensive therapy and circadian blood pressure profiles: a retrospective analysis utilising cumulative sums

The results of previous studies on the effects of antihypertensive agents on circadian blood pressure patterns are inconclusive, possibly due to the lack of a simple, objective, universally accepted method of quantifying circadian blood pressure profiles. In order to investigate for differences in the effects of antihypertensive drugs on circadian changes we utilised a recently described modified cumulative sums technique to quantify circadian alteration magnitude (CAM). CAM is simply calculated as the difference between crest and trough blood pressures, the mean blood pressures of the 6-h periods of highest and lowest sustained pressures respectively. The records from all 24-h ambulatory blood pressure monitoring performed over a 7 year period on subjects either on no medication (1208), or on treatment with a single first-line antihypertensive agent (578), were examined retrospectively. A sample (n = 40) stratified for trough diastolic blood pressure, age and sex was randomly selected from each of the following 5 groups: subjects on no medication, and subjects being treated with bendrofluazide, atenolol, class 2 calcium-channel blockers or captopril alone. Untreated subjects, those on bendrofluazide and those on a class 2 calcium channel blocker had similar circadian patterns. Subjects on atenolol therapy (25.9 +/- 1.7/18.3 +/- 1.3, systolic CAM +/- SE/diastolic CAM +/- SE) had attenuated circadian changes (p < 0.05) when compared to the untreated group (29.8 +/- 1.8/23.6 +/- 1.1), while those on captopril (34.9 +/- 2.4/25.7 +/- 1.8) exhibited markedly increased systolic and diastolic circadian blood pressure swings, which differed from those of the atenolol treated group (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The application of large Gaussian mixed models to the analysis of 24 hour ambulatory blood pressure monitoring data in clinical trials

We propose the use of Gaussian mixed models to analyse statistically 24 hour ambulatory blood pressure data from clinical trials. We develop specific models and apply them to data from a clinical study that compares two angiotensin-converting enzyme inhibitors. We investigate and discuss computing issues related to the implementation of such methods. We conclude that this methodology provides a sophisticated but practical approach to the analysis of such data.

A comparison of amlodipine with enalapril in the treatment of moderate/severe hypertension

1. The safety and efficacy of amlodipine vs enalapril as monotherapy was evaluated in patients with moderate/severe hypertension (supine DBP 105-125 mm Hg, SBP 140-220 mm Hg). 2. After 2 weeks placebo treatment 31 patients were randomised by the technique of minimisation in an observer-blind study to receive once daily treatment with either amlodipine (15 patients) 5-10 mg, or enalapril (16 patients) 5-20 mg for 8 weeks. The study design concluded with 2 weeks placebo treatment. In addition to clinic measurements, home blood pressure monitoring (Copal UA-251) was performed during the study. 3. Clinic supine systolic blood pressure was reduced from 177 to 152 mm Hg (amlodipine) and 183 to 169 mm Hg (enalapril) (95% CI for the intergroup difference -22.1, 0.3, P = 0.06) after 8 weeks treatment. 4. Clinic supine diastolic blood pressure was reduced from 110 to 93 mm Hg (amlodipine) and 109-102 mm Hg (enalapril) (95% CI for the intergroup difference -17.7, -2.7, P < 0.01) after 8 weeks treatment. 5. Home blood pressure recordings confirmed these reductions in blood pressure. Although the reduction in blood pressure was greater for the amlodipine treated group, the differences between treatments were not statistically significant. 6. Both drugs were reasonably well tolerated. The adverse events occurring most frequently in the amlodipine group were headache (5), peripheral oedema (3), upper respiratory infection (3) and anxiety (2). The adverse events occurring most frequently in the enalapril treated patients were headache (6), dizziness (3) and upper respiratory infection (2).

Trandolapril. How does it differ from other angiotensin converting enzyme inhibitors?

Among the physicochemical, pharmacokinetic and pharmacodynamic properties that differentiate trandolapril from other angiotensin converting enzyme (ACE) inhibitors, the most clinically relevant ones are those that contribute to the long duration of action of the drug. The long elimination half-life of trandolapril and its strong lipophilicity, high ACE inhibitor potency and high affinity for the ACE cause the drug to have a long biological half-life. The long duration of action of trandolapril may be demonstrated experimentally; near total ACE inhibition is observed 24 hours after single dose administration and there is significant ACE inhibition 72 hours following drug withdrawal after long term therapy. We have analysed the duration of blood pressure lowering during long term therapy with commercially available ACE inhibitors in published studies using ambulatory blood pressure monitoring. On the basis of results from 19 studies undertaken in patients with mild to moderate hypertension, it was possible to reconstruct the curve of the magnitude of blood pressure changes against time. Mean trough: peak ratio calculations showed that once-daily administration produced ratios higher than 50% with enalapril (40 to 80%), lisinopril (40 to 70%) and trandolapril (50 to 100%). Other ACE inhibitors had trough: peak ratios lower than 50%. Despite many methodological limitations, this literature analysis demonstrates that trandolapril has a blood pressure-lowering effect for the full 24-hour period. Studies in which a dose is occasionally omitted show that the blood pressure-lowering effect of trandolapril may last beyond 24 hours.

24-hour blood pressure measurement in antihypertensive drug trials: data requirements and methods of analysis

Non-invasive ambulatory blood pressure monitoring is an appropriate technique for the identification of the target population requiring antihypertensive treatment, since the systematic bias seen in casual clinic measurement is removed. The use of the technique in controlled clinical trials leads to a reduction in the sample size required to show a treatment difference in antihypertensive effect compared to sporadic single measurements, although in practice the number of recruited patients can considerably exceed the number of evaluable patients, due to poor compliance or incompleteness of data. In addition, the equality of observation essential in clinical trials cannot be controlled to the same degree as is possible with clinic measurements. Comparison of estimators of the overall characteristic blood pressure reveals that the 24-hour mean value produces an adequate estimator. A description of the individual blood pressure profile is obtained using smoothing procedures, the moving interval average providing a robust and simple approach. Clinically meaningful characteristics of the profile are difficult to define due to a dearth of information on prognostic importance of the features of the 24-hour blood pressure profile. Smoothed individual profiles can be combined to produce graphical descriptive treatment group summaries.

Comparison of angiotensin-converting enzyme inhibitors and calcium antagonists in the treatment of mild to moderate systemic hypertension, according to baseline ambulatory blood pressure level

This study was aimed at determining whether baseline ambulatory blood pressure (BP) levels influence the efficacy of angiotensin-converting enzyme inhibitors and calcium antagonists in the same manner. Accordingly, the ambulatory BP recordings of 236 mild to moderate hypertensive patients who had previously entered a clinical trial and had received either a calcium antagonist (n = 121) or an angiotensin-converting enzyme inhibitor (n = 115) were reviewed. The inclusion criterion was a clinic diastolic BP between 95 and 115 mm Hg at the end of the placebo period. Patients were classified according to the difference between their observed and predicted ambulatory BP (the latter assessed by regressing the observed ambulatory BP on the clinic BP). Reduction in ambulatory systolic and diastolic BP seemed to be greater (p less than 0.0001, p = 0.01) in patients receiving an angiotensin-converting enzyme inhibitor than in those who were given a calcium antagonist. However, analysis of variance showed (1) there was a significant interaction (F = 6.37 p = 0.01) between the pharmacologic class and the baseline systolic ambulatory BP; and (2) the difference in diastolic ambulatory BP reduction between both classes was no longer significant when adjusted for baseline diastolic ambulatory BP. In patients with higher than predicted ambulatory BP levels, angiotensin-converting enzyme inhibitors and calcium antagonists had roughly a similar effect (reduction in systolic BP, 9 +/- 8% vs 7 +/- 6%, p = not significant; reduction in diastolic BP, 11 +/- 8% vs 8 +/- 6%, p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Enalapril. A reappraisal of its pharmacology and therapeutic use in hypertension

Enalapril, an angiotensin converting enzyme (ACE) inhibitor usually administered orally once daily, decreases blood pressure by lowering peripheral vascular resistance without increasing heart rate or output. It is effective in lowering blood pressure in all grades of essential and renovascular hypertension. Patients not responding adequately to enalapril monotherapy usually respond with the addition of a thiazide diuretic (or a calcium antagonist or beta-blocker), and rarely require a third antihypertensive agent. Enalapril is at least as effective as other established and newer ACE inhibitors, and members of other antihypertensive drug classes including diuretics, beta-blockers, calcium antagonists and alpha-blockers, but therapy with enalapril may be less frequently limited by serious adverse effects or treatment contraindications than with other drug classes. The most frequent adverse effect limiting all ACE inhibitor therapy in clinical practice is cough. This favourable profile of efficacy and tolerability, and the substantial weight of clinical experience, explain the increasing acceptance of enalapril as a major antihypertensive treatment and supports its use as logical first-line therapeutic option.

[The significance of 24-hour blood pressure monitoring in the diagnosis and therapy of arterial hypertension]

The use of ABPM allows an improved assessment of blood pressure (BP) and therefore of the individual cardiovascular risk. It is able to identify patients who truly need therapy more exactly. Mostly patients with white coat hypertension who don't need therapy are identified. Furthermore, ABPM correlates more closely to target organ damage and to cardiovascular morbidity and mortality. This may be helpful to treat especially those patients who truly need therapy. BP exhibits a typical circadian rhythm with the highest values during the early morning hours and a decline during the night. A change of the day/night rhythm during shift work leads to an adaptation of BP rhythm. The early morning rise of BP and heart rate is accompanied by hemodynamic, rheological and biochemical alterations, which together may contribute to the increased frequency of vascular complications during the morning hours. The nightly decline of BP is often absent in patients with secondary hypertension and cardiac or renal organ damage. A lack of the nocturnal BP decline should therefore lead to further patients' evaluation. Elevated nocturnal BP seems to worsen the prognosis. ABPM offers better individual control of BP in patients on treatment and therefore is helpful to optimize the treatment. A more exact individual BP control during the awakening and sleeping period is possible as well as an avoidance of overtreatment. Patients could be protected both from prescription of too many drugs and from lowering BP too much. A further advantage lies in an improved control of patients with nocturnal hypertension.