Effects of celiprolol on systemic and forearm circulation in hypertensive patients: a double-blind cross-over study versus metoprolol

Vasodilating beta-adrenoceptor blockers as cardiovascular therapeutics

beta-Adrenoceptor blocking agents (beta-blockers) have been established as therapeutics for treatment of patients with hypertension, ischemic heart diseases, chronic heart failure, arrhythmias, and glaucoma. However, their clinical use is limited because some patients are adversely affected by their side effects. The discovery of cardioselective (beta(1)-selective) blockers has overcome some of the problems. Current retrospective studies have revealed that vasodilating beta-blockers (so-called beta-blockers of the third generation) have advantages over the conventional type of beta-blockers in terms of minimizing the adverse effects and improving the disease-derived dysfunction, thus enhancing the quality of life variables. Some of the possible advantages include improvement of insulin resistance, decrease in low-density lipoprotein cholesterol in association with increase in high-density lipoprotein cholesterol, attenuation of bronchial asthma attack and respiratory dysfunction, alleviation of coronary vasospasm provocation, peripheral circulatory disturbances, and erectile dysfunction, and better patient compliance. Release of nitric oxide, antioxidant action, beta(2)-adrenoceptor activation, Ca(2+) entry blockade, and other mechanisms underlying the vasodilating action may be responsible for the beneficial therapeutic effects of these agents.

Effects of ACE inhibitor therapy on derived central arterial waveforms in hypertension

Large artery properties constitute an important component of left ventricular afterload in hypertension. The present study examined whether such properties were particularly responsive to angiotensin converting enzyme inhibitor therapy. A prospective, randomized, 12-week study in 138 previously treated hypertensive subjects, in 67 of whom usual treatment (UC) was replaced with perindopril (P) therapy. Large artery properties were assessed as central arterial pressure augmentation determined by applanation tonometry of the radial artery and a transfer function. At baseline both augmentation index (AI, %) and pressure (AP, mm Hg) were related to body size, heart rate, and gender. In addition AP was related to age and systolic blood pressure (BP). After 12 weeks of treatment AP decreased significantly in both perindopril and UC groups, whereas AI only decreased significantly (151.7%+/-2.3% to 144.9%+/-2.6%) in those treated with perindopril. Decreases in AP (-4.2+/-0.9 mm Hg v -1.9+/-0.7 mm Hg) and AI (-6.8%+/-2.2% v -2.2%+/-2.5%) from week 0 to week 12 were greater in the perindopril-treated group, but differences between groups failed to reach statistical significance (P = .05 and .09, respectively). The change in AI during the 12-week treatment period was dependent on the initial heart rate (P < .001), systolic BP (P < .05), weight (P < .001), and sex (P < .001), but not on treatment group (P > .5). Al at 12 weeks was negatively correlated with heart rate but regression slopes for the association were virtually identical for perindopril and UC groups. Perindopril treatment produces a greater decrease in AI than continuation with previous therapy, but this can be largely explained by hemodynamic changes rather than direct arterial effects.

Pulse pressure--a review of mechanisms and clinical relevance

The goal of this study was to review the origin, clinical relevance and treatment of pulse pressure (PP). Elevated PP is increasingly being recognized as a risk factor for cardiovascular, particularly coronary, disease. Pulse pressure is discussed in terms of both Windkessel and distributive models of the arterial circulation. Pulse pressure arises from the interaction of cardiac ejection (stroke volume) and the properties of the arterial circulation. An increased stiffness of the aorta and large arteries leads to an increase in PP through a reduction in arterial compliance and effects on wave reflection. A number of factors are known to influence arterial wall behavior and, therefore, PP. In addition to the effects of aging and blood pressure on arterial wall elasticity, there is some evidence that atherosclerosis, per se, amplifies these effects. Thus, the relationship between PP and coronary disease may be bidirectional. A number of dietary and lifestyle interventions have been shown to modify large artery behavior. These include aerobic exercise training and consumption of n-3 fatty acids. Conversely, strength training is associated with an increase in arterial stiffness and a higher PP. The effects of antihypertensive medication have been extensively studied, but many studies are difficult to interpret because of concomitant change in blood pressure, and to a lesser degree, heart rate. However a number of studies do suggest direct arterial wall effects, particularly for angiotensin-converting enzyme inhibitors. A distributed compliance model of the arterial circulation provides a framework for understanding the causes, effects and potential treatment of elevations in PP.

Large artery stiffness in hypertension

EFFECTS OF HYPERTENSION ON LARGE ARTERIES: The mechanical properties of large arteries make a major contribution to cardiovascular haemodynamics through the buffering of stroke volume and by propagation of the pressure pulse. A sustained increase in blood pressure often leads to stiffness of the large arteries, especially when other risk factors are present. The increased stiffness, in turn, aggravates hypertension by increasing systolic blood pressure and can induce cardiac hypertrophy and arterial lesions. Epidemiological studies strongly suggest that subjects with stiffer arteries have a high pulse pressure, and that stiffening of large arteries is associated with excess morbidity and mortality independently of other cardiovascular risk factors. ENVIRONMENTAL AND GENETIC FACTORS: Apart from high blood pressure and ageing, various environmental and genetic factors that influence the composition of the extracellular matrix of the arterial wall can increase arterial stiffness. Clinical studies suggest that the presence of some genotypes may be a particularly important risk marker for arterial stiffness, and may modulate the effects of hypertension, ageing and lipids on large arteries. EFFECTS OF ANTIHYPERTENSIVE DRUGS: The development of accurate, non-invasive methods has now made it possible to detect alterations of the large arteries. Among antihypertensive drugs, angiotensin converting enzyme inhibitors and calcium channel blockers have proved to be highly effective in improving large artery compliance, and have shown no adverse effects on metabolic factors that can alter arterial structure and function such as lipids, plasma glucose and insulin tolerance. Therefore these drugs may be particularly suitable for treating patients with increased arterial stiffness. Finally, a determination of genotypes may be helpful in the future in choosing antihypertensive therapy.

Transdermal delivery of metoprolol. II: In-vitro skin permeation and bioavailability in hairless rats

The absolute bioavailability of metoprolol (MP) was evaluated following oral and transdermal administration in hairless rats. The absolute bioavailability of MP following oral administration was 3.48 +/- 1.73%, indicating that MP is subject to extensive hepatic first-pass metabolism. Transdermal delivery of MP, via an adhesive delivery device, resulted in a bioavailability of 30.07 +/- 4.84%, indicating that the transdermal delivery of MP can significantly increase systemic bioavailability compared with oral administration. Preliminary skin irritation studies indicated that neither MP nor the adhesive used in the device caused any appreciable skin irritation in the hairless rats.

Effect of beta-blockade on exercise capacity in hypertensive subjects: a one-year double-blind study of celiprolol and metoprolol

To assess the effect of beta-blocker antihypertensive therapy on exercise capacity, 40 patients randomized to celiprolol 200 mg and metoprolol 100 mg daily in a double-blind fashion were studied after a month of placebo and a year of active treatment. Both drugs normalized office blood pressure and produced echocardiographic and electrocardiographic left ventricular hypertrophy regression. In symptom-limited maximal stress tests before and after treatment, exercise duration increased with (p < 0.0001) celiprolol (513-700 seconds) and metoprolol (520-634 seconds), although more with the former (p = 0.02). Resting heart rate was reduced with both, more with metoprolol (p < 0.001), while heart rate at peak exercise was reduced similarly with both medications (p < 0.005). Blood pressure at peak exercise was reduced with both celiprolol (217-184 mmHg; p = 0.0002) and metoprolol (218-185 mmHg, p < 0.0001) to a similar degree (p = NS). Exercise parameters were not related to patient age or the degree of left ventricular hypertrophy regression (p = NS). It is concluded that beta-blocker antihypertensive therapy improves exercise capacity, decreasing heart rate and blood pressure responses to stress, irrespective of left ventricular structural changes.

Adverse reactions with beta-adrenoceptor blocking drugs. An update

beta-Adrenoceptor blocking drugs are widely used throughout the world, and serious adverse reactions are relatively uncommon. Many of those that do occur, including bronchospasm and peripheral ischaemia, are due primarily to blockade of beta 2-adrenoceptors. Recently developed beta-blockers with enhanced beta 1-selectivity and partial beta 2-agonist activity appear, in general, to have lesser effects upon airways function and vascular resistance, but none are regarded as being entirely 'safe' in patients with asthma. In the treatment of hypertensive patients with co-existing airways disease there are now effective alternatives to the beta-blockers, including calcium antagonists, alpha-adrenoceptor antagonists and angiotensin converting enzyme (ACE) inhibitors. However, in the presence of ischaemic heart disease, beta-blockers have specific advantages and may still be considered necessary in patients with airways disease. In this situation, agents with beta 2-agonist activity are preferable to 'conventional' beta-blockers. However, there is still some risk that bronchospasm may occur in certain individuals, and the bronchodilator response to inhaled beta 2-agonists might be impaired. In patients with peripheral vascular disease, beta-blockers with beta 2-agonist activity are less likely to worsen the symptoms and signs of peripheral ischaemia, and may reduce the prevalence of peripheral coldness, a common adverse effect of beta-blockers. There is concern that beta-blockers may have significant central effects, including impairment of memory and concentration, although these are difficult to quantify. A number of pharmacologically unpredictable adverse reactions may occur rarely, including skin reactions, alopecia and arthropathy.

Effect of pretreatment with the selective beta 1-adrenoceptor antagonist bisoprolol on the subsequent cardiovascular actions and beta-adrenoceptor subtype specific occupancy of celiprolol in healthy man

The cardiovascular effects at rest and during exercise and beta 1- and beta 2-adrenoceptor occupancy following a single dose of 1200 mg celiprolol p.o. were investigated in 8 healthy subjects with or without pretreatment with a single dose of 20 mg bisoprolol p.o., using a placebo-controlled, 2-way cross-over design. The ergometric responses of heart rate (HR) and systolic blood pressure (SBP) after celiprolol were reduced to a similar extent as after bisoprolol, but the cardiovascular function at rest was affected in a different way: there was a rise in HR, clear enhancement of cardiac systolic performance, and a considerable drop in the estimated total peripheral vascular resistance, associated with median beta 1-RRA and beta 2-RRA occupancies of 88 and 34%, respectively. The cardiovascular effects of celiprolol were not affected by pretreatment with bisoprolol. Celiprolol thus binds extensively to beta 1-adrenoceptors, moderately to beta 2-adrenoceptors, acts as beta 1-adrenergic antagonist (exemplified by the ergometric effects) but has vasodilator, positive chronotropic and cardiac systolic performance enhancing properties, which do not involve either direct or indirect beta 1-adrenergic agonism, but which might reflect beta 2-adrenergic agonism.

Effects of the single and repeated administration of benazepril on systemic and forearm circulation and cardiac function in hypertensive patients

The hemodynamic and cardiac effects of the new angiotensin-converting enzyme inhibitor, benazepril, were studied in 28 hypertensives in a double blind, placebo-controlled, between-patient study. Hemodynamic studies were performed noninvasively by means of M-mode echo (central hemodynamics and left ventricular systolic function), 2-D echo-Doppler (left ventricular diastolic function), and pulsed Doppler flowmetry (forearm circulation). Examinations were done at the end of a placebo run-in period and 3 hours after benazepril administration, both on the first day and after 6 weeks of treatment (10 or 20 mg once daily, according to patient response). In comparison with placebo, benazepril reduced systolic (p = 0.04) and diastolic (p = 0.003) blood pressure, because of a significant reduction in systemic vascular resistance (p = 0.03), while cardiac output was unchanged. Forearm vascular resistance was reduced and brachial artery compliance increased, although not to a statistically significant level (both p = 0.07). Both systolic and diastolic left ventricular function were positively influenced by the afterload reduction: End-systolic stress was reduced by 12% (p = 0.07), as was the late diastolic peak flow velocity (p = 0.02). All hemodynamic changes were evident after acute benazepril administration, and no differences was observed between acute and repeated treatment. We conclude that, similar to other ACE-inhibitors, benazepril reduces blood pressure through a reduction in vascular resistance, while cardiac output and heart rate are unaffected. These hemodynamic effects occur as early as after the first administration and exert a favorable influence on left ventricular dynamics.

Clinical safety and efficacy of celiprolol

The management of essential hypertension requires therapeutic selections that are not only effective in reducing diastolic blood pressure but are also tailored to the individual patient, with minimal effect on patient demographics, concurrent illnesses, and cardiovascular risk factors. Celiprolol hydrochloride is a new highly cardioselective vasodilating beta-adrenoceptor antagonist that has been proven effective and safe for the treatment of essential hypertension. It is comparable to other therapies in blood pressure control while demonstrating an excellent safety profile, favorable hemodynamic activity, and minimal effects on other cardiovascular risk factors. Celiprolol may offer the physician a unique therapeutic alternative.

Evaluation of celiprolol, a new cardioselective beta 1-adrenergic blocker with vasodilating properties, in the treatment of mild to moderate hypertension in the elderly

Celiprolol hydrochloride is a cardioselective beta 1-adrenergic antagonist with partial agonist activity. The studies discussed were designed to assess celiprolol's pharmacokinetic disposition, its efficacy versus placebo and other beta blockers, its relative safety profile, and its therapeutic ratio in the elderly population. The results of a postmarketing surveillance study are also presented. Pharmacokinetic results indicate good dose-related bioavailability in the elderly, no accumulation on multiple dosing, and pharmacokinetics equivalent to those in a younger age group. Celiprolol effectively lowers blood pressure in elderly patients with mild to moderate hypertension, resulting in reductions of 12-15 mmHg and 8-11 mmHg in systolic and diastolic blood pressures, respectively. A clinically insignificant reduction in resting pulse rate is observed with celiprolol treatment. Its adverse experience profile is equivalent to that of placebo, and the incidence of beta-blocker-associated side effects is lower compared with that of atenolol and propranolol. Celiprolol also effectively controlled hypertension in the elderly in the postmarking surveillance study. Collectively, the results of these studies demonstrate that the pharmacokinetics and efficacy of celiprolol in the treatment of mild to moderate hypertension are equivalent in younger and older populations, and that the therapeutic ratio (i.e., efficacy/safety) of celiprolol is superior to that of atenolol and propranolol in the elderly.

Effect of celiprolol on large and small arteries of the forearm circulation in hypertensive patients

Celiprolol, a new highly cardioselective beta blocker, also has direct vasodilating properties. Since the noninvasive echo Doppler technique applied to the forearm circulation (brachial artery) allows the differentiation of arteriolar vasodilation (revealed by the increasing arterial blood flow velocity) from vasodilation of large arteries (shown by an increase in arterial diameter), it seems important to study the site of celiprolol's vasodilating effect. Thirty-five hypertensive patients, (21 male, 14 female; mean age, 59 +/- 11, range 42-79 years) were treated with increasing doses of celiprolol, 200 and 400 mg, over 15 days. The duplex echo Doppler technique (Aloka 7.5 M Hz probe) was used before and during each celiprolol dose period. Statistical analysis was performed by Student's paired t test. It was observed that celiprolol significantly increases the brachial artery diameter in a dose-dependent manner, and also increases the blood flow velocity (not being direct dose-related). Since the increase in diameter was clear with a higher dose, a dose-dependent increase in blood volume, a decrease in peripheral resistance, and an increase in compliance followed. Since the higher dose of celiprolol did not further reduce blood pressure (BP) in comparison to the lower dose, and a dose-dependent increase in arterial diameter and compliance occurred and a vasodilating effect of celiprolol on arterial wall ensued that was not related to BP. In conclusion, in the doses used, celiprolol dilates both arterioles and large arteries, but the mechanism of action needs to be clarified.

The central and peripheral hemodynamics of celiprolol

The cardiovascular effects of celiprolol in healthy subjects and in those with cardiovascular disease and hypertension are reviewed. Unlike classic beta-blockers, celiprolol does not depress cardiac contractility at rest while interfering to a lesser extent with cardiac function during exercise. Furthermore, celiprolol causes systemic vasodilatation, which, in hypertension, is mainly responsible for the blood pressure-reducing effects of the drug. Vasodilatation results from the reduction in vascular resistance of skeletal muscle tissues, but celiprolol also produces dilatation of vascular areas such as the kidney. This prevents a reduction in renal blood flow and consequently the salt and water retention associated with impaired perfusion. It is possible that such hemodynamic changes are dependent not on celiprolol's selective beta1-receptor-blocking properties but on certain additional properties.