Lipid effects of celiprolol, a new cardioselective beta-blocker, versus propranolol

Comparative evaluation of atenolol and metoprolol on cardiovascular complications associated with streptozotocin-induced diabetic rats

Recently, various clinical studies have indicated that lipophilic β-blockers reduce the coronary mortality in diabetic patients; however, systematic studies have not been reported. The objective of the present investigation was to compare the effects of chronic treatment with metoprolol and atenolol on cardiovascular complications in streptozotocin (STZ)-induced diabetic rats. Injection of STZ produced hyperglycemia, hypoinsulinemia, hyperlipidemia, increased blood pressure, cardiac hypertrophy, reduction in heart rate, and structural alterations in cardiac tissues. Metoprolol and atenolol effectively prevented the development of hypertension in diabetic rats. Metoprolol treatment produced a slight but significant reduction in serum glucose levels with elevation in serum insulin levels, while atenolol produced a slight increase in glucose levels but no effect on insulin levels. Moreover, neither metoprolol nor atenolol treatment reduced the elevated cholesterol levels in diabetic rats. Metoprolol treatment significantly prevented STZ-induced increase in triglyceride levels, but atenolol failed to produce this effect. Metoprolol exhibited a minimal improvement in STZ-induced bradycardia, whereas atenolol produced a further reduction in heart rate. Histological examination showed metoprolol treatment also prevented STZ-induced hypertrophy and some of the alterations in cardiomyocytes. In conclusion, our data suggest that metoprolol has some beneficial effects over atenolol with respect to cardiovascular complications associated with diabetes mellitus.

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.

Studies on the pharmacokinetics and pharmacodynamics of propranolol in hyperlipidemia

The lipophilic beta-adrenoreceptor antagonist propranolol has been studied to define its pharmacokinetic and pharmacodynamic characteristics in hyperlipidemic patients. A total of 48 subjects were allocated to four study groups: (1) healthy volunteers, (2) hypercholesterolemic patients, (3) hypertriglyceridemic subjects, and (4) patients with a mixed form of hyperlipidemia. Propranolol was given orally as a single dose of 80 mg. Heart rate was measured during 12 hours. At each point, the concentrations of propranolol were estimated. Moreover, heart rate and arterial systolic blood pressure were examined at rest and after a submaximal exercise test 3 hours after administration of propranolol (i.e., at the peak of propranolol concentration in the blood serum). A significant increase in the area under the serum concentration-time curve (AUC) by 39% and a reduction of the volume of distribution and total body clearance by 48% and 46%, respectively, without a significant change in the half-life time, were observed in patients with hypertriglyceridemia in comparison with the control group. The acceleration of exercise heart rate and the elevation of systolic blood pressure were comparable in all groups in the study, whereas blood serum concentrations of propranolol in patients with hypertriglyceridemia (group 3) and the mixed form of hyperlipidemia (group 4) were markedly altered from those observed in normolipemic subjects. No relationship between the concentration of propranolol and the heart rate in the group with hypertriglyceridemia was seen. In the light of this study, the authors suggest that lipid metabolism disturbances do not affect the pharmacodynamics of propranolol.

Effects of celiprolol vs. nifedipine on serum lipoproteins in patients with mild to moderate hypertension

During a double-blind, randomized study in hypertensive patients, changes in plasma lipid and lipoprotein levels during treatment with celiprolol were compared with those occurring during nifedipine treatment. Fifty-three patients (28 men and 25 women) with mild-to-moderate hypertension, aged 20-64 years, were studied. After a 1-month placebo run-in period, patients were randomly assigned to receive either nifedipine (40 mg daily) or celiprolol (200 mg daily), each time using a double-dummy technique. After 6 weeks, dosages of each drug could be doubled. After 6 weeks, there were no differences in plasma lipids between the two treatment groups. However, the changes after 12 weeks of treatment were different (p < 0.05) between the groups, leading to lower levels of plasma esterified cholesterol, low-density lipoprotein (LDL) cholesterol, and apoprotein AI, AII, and B in the celiprolol group. Plasma lecithin cholesterol acyltransferase activity (LCAT) was not modified. The present study showed that celiprolol was at least equivalent to nifedipine in terms of secondary effects on plasma lipids and lipoprotein.

Comparative effects of atenolol versus celiprolol on serum lipids and blood pressure in hyperlipidemic and hypertensive subjects

Antihypertensive drugs may affect serum lipoprotein levels in mixed populations but data in hyperlipidemic patients are scanty. Atenolol versus celiprolol effects on serum lipoproteins were compared in 159 hyperlipoproteinemic hypertensive patients. This was a randomized, double-blind, parallel-group, positive-controlled multicenter trial with centralized lipoprotein laboratory and diet constancy monitoring. Blood pressure reduction and serum lipoprotein and apoprotein levels were monitored for 3 months. Both drugs reduced systolic and diastolic blood pressures. Atenolol had greater effects than celiprolol on diastolic pressure, but effects on systolic blood pressure were not different. Patients receiving atenolol had lower serum high-density lipoprotein cholesterol levels and higher low-density lipoprotein/high-density lipoprotein cholesterol ratios, whereas patients treated with celiprolol showed no contrasting changes. These differences in lipoprotein levels between drug treatment groups were statistically significant at weeks 9 and 12. The difference between drug treatments was also significant if the values of the 9- and 12-week visits were averaged. Patients taking atenolol had statistically significantly higher serum levels of total cholesterol, triglycerides and apoprotein B at 9 weeks. These divergent directional changes were consistent throughout and statistically significantly different between drugs.

Dose-response relationships with antihypertensive drugs

A variety of antihypertensive drugs have been introduced into clinical practice at excessively high dose. Examples include most thiazide diuretics, propranolol, oxprenolol, atenolol, methyldopa, hydralazine and captopril. These very high doses have usually resulted from studies in which doses have been increased at regular intervals until the desired antihypertensive effect has been achieved or until unacceptable adverse effects have resulted. Frequently the starting doses were too high and the intervals between dose adjustment too short. In many cases these large doses resulted in unnecessary adverse effects--the adverse biochemical effects of thiazide diuretics, nephrotic syndrome, taste disturbances and neutropenia with captopril, the lupus syndrome with hydralazine and the central nervous system effects of methyldopa. Parallel group design with single doses and sufficient statistical power to distinguish between the upper and lower ends of the antihypertensive dose-response relationship should replace the dose-escalating design.

Antihypertensive agents, serum lipoproteins and glucose metabolism

Effective blood pressure control with traditional high-dose diuretic therapy has led to a distinct decrease in cerebrovascular morbidity and mortality, but failed to achieve a satisfactory reduction of coronary complications and sudden death. The same applies also for beta blockers, although they have been shown to be effective in secondary prevention of myocardial infarction. It is suspected that conventional antihypertensive treatment has an unfavorable effect on coronary risk factors other than hypertension. For instance, thiazide-type diuretics can impair glucose tolerance and increase the potentially atherogenic serum low-density lipoprotein (LDL) cholesterol fraction and triglycerides. Beta blockers without partial intrinsic sympathomimetic activity increase serum triglycerides and tend to lower the potentially antiatherogenic high-density lipoprotein (HDL) cholesterol. Certain beta blockers may also impair glucose tolerance, particularly when they are combined with diuretics. Calcium channel blockers, angiotensin converting-enzyme inhibitors and alpha 1-receptor blockers do not adversely affect lipoprotein or carbohydrate profiles. The latter two drug classes may even increase insulin sensitivity, and alpha 1 blockers may also slightly improve lipid metabolism. The prognostic relevance of drug-induced dyslipidemia and/or glucose intolerance awaits further clarification. In the meantime, it is of clinical interest that several of the generally available antihypertensive drugs seem to be metabolically neutral or sometimes perhaps even potentially beneficial with regard to the lipoprotein and carbohydrate metabolism.

Metabolic considerations in the choice of therapy for the patient with hypertension

The objective of treating patients with hypertension is not simply to reduce blood pressure but rather to prevent the associated morbidity and mortality. Recent assessments of clinical trials have shown that while the risk of stroke is consistently lower with antihypertensive therapy, the same degree of success has not been demonstrated for coronary artery disease (CAD). Although there are many explanations of why we have not done as well in preventing CAD, one possibility is that the therapy used in clinical trials, primarily thiazide diuretics and beta-adrenoreceptor blockers, has increased the patient's risk of developing coronary atherosclerosis or lethal arrhythmias. Four classes of antihypertensive agents are recommended for initial therapy--thiazide diuretics, beta-adrenoreceptor blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium entry blockers. The metabolic effects of thiazide diuretics include electrolyte disturbances (hypokalemia, hypomagnesemia, and hyponatremia), dyslipidemia (increased triglycerides), abnormalities of glucose metabolism (hyperglycemia, hyperinsulinemia, and peripheral insulin resistance), and hyperuricemia. beta-Adrenoreceptor blockers have many of the same metabolic adverse reactions. beta-Adrenoreceptor blockers without intrinsic sympathomimetic activity (ISA) also cause dyslipidemias (lowered high-density lipoprotein cholesterol and increased triglycerides) and abnormalities of glucose metabolism (hyperglycemia, hyperinsulinemia, and peripheral insulin resistance). beta-Adrenoreceptor blockers with ISA and third-generation beta-blockers with selective partial agonist activity (celiprolol and dilevalol) do not cause dyslipidemia and to date do not appear to induce abnormalities in glucose metabolism. ACE inhibitors may decrease triglycerides and increase high-density lipoprotein cholesterol, and captopril may improve insulin sensitivity. Calcium entry blockers are metabolically neutral.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Effects of celiprolol and other antihypertensive agents on serum lipids and lipoproteins

The expected reduction in coronary heart disease morbidity and mortality has not been observed in intervention trials with antihypertensive agents, and attention has focused on the lipid and lipoprotein effects of antihypertensive agents. Diuretics, especially thiazides, chlorthalidone, and the loop diuretics, increase total and low-density lipoprotein cholesterol and triglyceride levels with generally no significant change in high-density lipoprotein cholesterol. Selective and nonselective beta-blockers decrease high-density lipoprotein cholesterol and increase triglyceride levels, whereas those with intrinsic sympathomimetic activity do not significantly alter lipid and lipoprotein levels. Celiprolol, a beta-blocker with vasodilatory effects, appears to favorably affect lipid and lipoprotein levels as do the alpha 1-adrenergic blockers. The other commonly used antihypertensive agents do not produce significant effects.