A Randomised Comparison of the Effects of Nebivolol and Atenolol with and without Chlorthalidone on??the Sexual Function of Hypertensive Men

Therapeutic management of erectile dysfunction: The AFU/SFMS guidelines

CONTEXT

Erectile dysfunction (ED) is a common sexual disorder. In France, recent evidence-based guidelines are lacking.

AIM

To provide practice guidelines on ED therapeutic management.

EVIDENCE ACQUISITION

Publications indexed in PubMed/Medline® between January 1999 and October 2023, were reviewed. For each clinical question, a level of evidence was attributed to the conclusions. These conclusions and the working group arguments were used to develop and grade (A-C) the recommendations.

RECOMMENDATIONS

ED management must be personalized. Phosphodiesterase 5 inhibitors (PDE5I) are recommended as first-line treatment (A). In patients with severe ED, a combination of PDE5I may be proposed as first- or second-line treatment (Expert Agreement, EA). Extra-cavernous or intra-urethral injections of alprostadil may be offered as first-line alternative to PDE5I or as second-line treatment (B). In case of unsatisfactory response to PDE5I or alprostadil alone, the combination of a PDE5I with intra-cavernosal or intra-urethral alprostadil may be proposed (EA). Vacuum therapy can be offered to all patients (B). Low-intensity extracorporeal shockwave therapy may be proposed to patients with mild or moderate ED, alone or in combination with PDE5I (B). Penile implants are indicated for patients with ED who are refractory or intolerant to pharmacological or mechanical treatments, or if they wish a permanent solution (B). Revascularization surgery may be offered to patients without comorbidities following pelvic trauma and ED with isolated arterial insufficiency (B). In addition to pharmaceutical, mechanical and/or surgical treatments, it is suggested to always consider educational interventions and counseling, lifestyle modifications and management of co-morbidities and curable causes.

Anti-hypertensive medications and erectile dysfunction: focus on β-blockers

PURPOSE

Although anti-hypertensive medications, including thiazides and β-blockers (BBs) in particular, have been suggested to cause erectile dysfunction (ED) their real contribution is still conflicting. The aim of this paper is to summarize available evidence providing an evidence-based critical analysis of the topic.

METHODS

An overall comprehensive narrative review was performed using Medline, Embase and Cochrane search. In addition, to better understand the impact of BBs on ED a specific systematic review was also performed.

RESULTS

The negative role of centrally acting drugs, such as clonidine and α-methyldopa, is well documented althuogh limited controlled trials are available. Angiotensin-converting enzyme inhibitors (ACEis), angiotensin receptor blockers (ARBs), and calcium-channel-blockers (CCBs) have neutral (CCBs) or even positive (ACEis and ARBs) effects on erectile function. Despite some preliminary negative reports, more recent evidence does not confirm the negative impact of thiazides. BBs should be still considered the class of medications more often associated with ED, although better outcomes can be drawn with nebivolol.

CONCLUSION

Sexual function should be assessed in all patients with arterial hypertension, either at diagnosis or after the prescription of specific medications. A close related patient-physician interaction and discussion can overcome possible negative outcomes allowing a successful management of possible side effects.

Effect of nebivolol monotherapy or combination therapy on blood pressure levels in patients with hypertension: an updated systematic review and multilevel meta-analysis of 91 randomized controlled trials

AIMS

To systematically appraise and summarize the available evidence from published randomized controlled trials considering the effect of nebivolol on blood pressure in patients with hypertension.

METHODS

Literature search was performed through Medline (via PubMed), Cochrane Library and Scopus until December 15, 2023. Double-independent study selection, data extraction and quality assessment were performed. Evidence was pooled with three-level mixed-effects meta-analysis.

RESULTS

In total, 7,737 participants with hypertension, who were treated with nebivolol, were analyzed across 91 RCTs. Nebivolol was associated with significantly greater reduction in office systolic and diastolic BP compared to placebo (MD = - 6.01 mmHg; 95% CI = [- 7.46, - 4.55] and MD = - 5.01 mmHg; 95% CI = [- 5.91, - 4.11], respectively). Moreover, resulted a similar reduction in systolic BP (MD = - 0.22 mmHg; 95% CI = [- 0.91, 0.46]) and a significantly greater reduction in diastolic BP compared to the active comparator (MD = - 0.71 mmHg; 95% CI = [- 1.27, - 0.16]). When considering the effect of nebivolol on 24-hour ambulatory BP, notable reductions were observed compared to placebo. In contrast, compared to the active comparators, there was no significant difference in systolic BP reduction, but a significant reduction in diastolic BP favoring nebivolol. Based on moderator analyses, the impact of nebivolol on the pooled estimates remained independent of the dose of nebivolol, age, male sex, trial duration, body mass index (BMI), baseline diabetes, heart failure, and baseline systolic and diastolic BP.

CONCLUSION

Nebivolol, compared to placebo, showed a significant BP reduction and was non-inferior to other active comparators in terms of BP reduction.

Physicians' attitudes toward beta-blockers for the treatment of hypertension in Italy, Poland, and Turkey

Despite substantial progress in understanding the complex pathophysiology, hypertension remains a serious public health challenge affecting over 1.2 billion adults aged 30-79 years worldwide. Appropriate knowledge of the different pharmaceutical classes of antihypertensive agents and an understanding of the characteristics of individual molecules are essential to optimize clinical outcomes in patients with hypertension. We conducted a computer-assisted web interviewing (CAWI) quantitative survey in Italy, Poland, and Turkey to investigate physicians' prescriptions, knowledge, and perceptions of antihypertensive drugs with a focus on β-blockers, to assess antihypertensive usage patterns and the reasons underlying prescription choices. The survey findings show that β-blockers retain a pivotal role in the management of hypertension and are prescribed more often for patients with cardiovascular comorbidities than for patients with diabetic comorbidities. In all three countries, nebivolol is the only β-blocker among the ones analyzed which is consistently prescribed to 20% or more of patients and is overall the most prescribed one for the population with comorbid diabetes. In terms of specific β-blockers' features, this study revealed knowledge gaps that underline the need for educational activities focused on the differences among β-blockers, which are important in choosing the most suitable agent for individualized antihypertensive therapy.

Nebivolol protects erectile functions compared to Metoprolol in hypertensive men with atherogenic, venogenic, psychogenic erectile dysfunction: A prospective, randomized, cross-over, clinical trial

INTRODUCTION

Both hypertension and β-blocker drugs used for treating hypertension (HT) can cause erectile dysfunction (ED). Nebivolol, unlike other β-blockers, may not cause impotence since it increases the release of Nitric Oxide (NO), which is the main mediator of erection. This study investigated the effect of Nebivolol and Metoprolol on erectile functions in hypertensive men.

MATERIALS AND METHODS

Married men whose blood pressure were >140/90 mmHg were included in the study. All patients were assessed for ED, and the cause of ED was then investigated. Nebivolol or Metoprolol was started for one month in all patients. After one-month drugless period, the β-blockers were switched. Blood pressures, pulses and sexual function tests were evaluated, and plasma NO levels were measured at the end of the treatments and during the drugless period.

RESULTS

There was no difference in antihypertensive efficacy between the two drugs (p = 0.828;0.194 for systolic and diastolic BP). Metoprolol caused a significant decrease in IIEF-5 score, whereas Nebivolol did not cause a decrease in IIEF-5 score on patients with psychogenic, arteriogenic, and venous failure related ED (respectively, p<0.001,0.004,0.005 for Metoprolol; p = 0.201,0.598,0.088 for Nebivolol). In the non-ED group, both drugs decreased the IIEF-5 score, but the decrease for Metoprolol (p = 0.001) was more than that for Nebivolol (p = 0.012). Plasma NO levels did not change with Metoprolol (p = 0.268) but increased with Nebivolol (p<0.001). There was a positive correlation between plasma NO values and IIEF-5 score used for the assessment of sexual functions (r = 0.284, p = 0.026).

CONCLUSION

Nebivolol may be advantageous in terms of preserving sexual functions because of increasing NO in eligible hypertensive male patients.

Sexual Dysfunction Among Patients With Chronic Kidney Disease

Sexual dysfunction (SD) in patients with chronic kidney disease is common and negatively impacts quality of life. SD is often under-appreciated because of overall low awareness. Diagnosis of SD is subjective, and manifestations can be different among men and women. Causes of SD are multifactorial, including psychological disorders, hormonal imbalances, vascular disorders, neurological disorders, and medication side effects. Non-specific approaches to improving sexual function include addressing underlying psychological disorders, promoting lifestyle modifications, optimizing dialysis care, and facilitating successful kidney transplantation, whereas treatment with phosphodiesterase type 5 inhibitor, hormone replacement, and mechanical devices can be offered to patients with specific indications.

Therapeutic Properties of Highly Selective β-blockers With or Without Additional Vasodilator Properties: Focus on Bisoprolol and Nebivolol in Patients With Cardiovascular Disease

Bisoprolol and nebivolol are highly selective β₁-adrenoceptor antagonists, with clinical indications in many countries within the management of heart failure with reduced left ventricular ejection fraction (HFrEF), ischaemic heart disease (IHD), and hypertension. Nebivolol has additional vasodilator actions, related to enhanced release of NO in the vascular wall. In principle, this additional mechanism compared with bisoprolol might lead to more potent vasodilatation, which in turn might influence the effectiveness of nebivolol in the management of HFrEF, IHD and hypertension. In this article, we review the therapeutic properties of bisoprolol and nebivolol, as representatives of “second generation” and “third generation” β-blockers, respectively. Although head-to-head trials are largely lacking, there is no clear indication from published studies of an additional effect of nebivolol on clinical outcomes in patients with HFrEF or the magnitude of reductions of BP in patients with hypertension.

Erectile Dysfunction as a Cardiovascular Risk Factor: Time to Step Up?

BACKGROUND

Erectile dysfunction (ED) is a major health problem that affects a significant proportion of the general population, and its prevalence is even higher in patients with CV risk factors and/or disease. ED and cardiovascular (CV) disease share several common pathophysiological mechanisms, and thus, the potential role of ED as a predictor of CV events has emerged as a significant research aspect.

OBJECTIVE

The purpose of this review is to present and critically discuss data assessing the relation between ED and CV disease and the potential predictive value of ED for CV events.

METHODS

A comprehensive review of the literature has been performed to identify studies evaluating the association between ED and CV disease.

RESULTS

Several cross-sectional and prospective studies have examined the association between ED and CV disease and found an increased prevalence of ED in patients with CV disease. ED was shown to independently predict future CV events. Importantly, ED was found to precede the development of overt coronary artery disease (CAD) by 3 to 5 years, offering a "time window" to properly manage these patients before the clinical manifestation of CAD. Phosphodiesterase type 5 inhibitors are the first-line treatment option for ED and were shown to be safe in terms of CV events in patients with and without CV disease.

CONCLUSION

Accumulating evidence supports a strong predictive role of ED for CV events. Early identification of ED could allow for the optimal management of these patients to reduce the risk for a CV event to occur.

The role of nebivolol in the management of hypertensive patients: from pharmacological profile to treatment guidelines

According to the most recent international guidelines, β-blockers maintain a central role in the management of hypertension, being recommended at any treatment step when there is a specific indication, such as heart failure, angina, postacute myocardial infarction, atrial fibrillation or pregnancy. However, β-blockers are not a homogeneous class: individual molecules differ in terms of pharmacological and clinical profile and are therefore suitable for different patient subtypes. In particular nebivolol, a third generation β₁-selective β-blocker with vasodilating properties, neutral metabolic effects and good tolerability, proved to have advantages over other β-blockers, which makes the drug suitable in a wide variety of hypertensive patients with or without comorbidities.

Update of the position paper on arterial hypertension and erectile dysfunction

: Sexual health is an integral part of overall health, and an active and healthy sexual life is an essential aspect of a good life quality. Cardiovascular disease and sexual health share common risk factors (arterial hypertension, diabetes mellitus, dyslipidemia, obesity, and smoking) and common mediating mechanisms (endothelial dysfunction, subclinical inflammation, and atherosclerosis). This generated a shift of thinking about the pathophysiology and subsequently the management of sexual dysfunction. The introduction of phosphodiesterase type 5 inhibitors revolutionized the management of sexual dysfunction in men. This article will focus on erectile dysfunction and its association with arterial hypertension. This update of the position paper was created by the Working Group on Sexual Dysfunction and Arterial Hypertension of the European Society of Hypertension. This working group has been very active during the last years in promoting the familiarization of hypertension specialists and related physicians with erectile dysfunction, through numerous lectures in national and international meetings, a position paper, newsletters, guidelines, and a book specifically addressing erectile dysfunction in hypertensive patients. It was noted that erectile dysfunction precedes the development of coronary artery disease. The artery size hypothesis has been proposed as a potential explanation for this observation. This hypothesis seeks to explain the differing manifestation of the same vascular condition, based on the size of the vessels. Clinical presentations of the atherosclerotic and/or endothelium disease in the penile arteries might precede the corresponding manifestations from larger arteries. Treated hypertensive patients are more likely to have sexual dysfunction compared with untreated ones, suggesting a detrimental role of antihypertensive treatment on erectile function. The occurrence of erectile dysfunction seems to be related to undesirable effects of antihypertensive drugs on the penile tissue. Available information points toward divergent effects of antihypertensive drugs on erectile function, with diuretics and beta-blockers possessing the worst profile and angiotensin receptor blockers and nebivolol the best profile.

Effects of Major Antihypertensive Drug Classes on Erectile Function: a Network Meta-analysis

PURPOSE

To determine the effect of major antihypertensive classes on erectile function (EF) in patients with or at high risk of cardiovascular disease.

METHODS

We performed a systematic review and frequentist network meta-analysis of randomized controlled trials assessing the effect of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, calcium channel blockers, and thiazide diuretics on EF compared to each other and to placebo (PROSPERO: CRD42020189529). Similarly, we performed a network meta-analysis to explore the effect of different β-blockers on erectile function (nebivolol, other vasodilating and non-vasodilating β-blockers, placebo). Records were identified through search of PubMed, Cochrane Library, and Scopus databases and sources of grey literature until September 2020.

RESULTS

We included 25 studies (7784 patients) in the qualitative and 16 studies in the quantitative synthesis. The risk of bias was concerning or high in the majority of studies, and inconsistency was also high. No significant differences in EF were demonstrated in the pairwise comparisons between major antihypertensive classes. Similarly, when placebo was set as the reference treatment group, no treatment strategy yielded significant effects on EF. In the β-blockers analysis, nebivolol contributed a beneficial effect on EF only when compared to non-vasodilatory β-blockers (OR 2.92, 95%CI 1.3-6.5) and not when compared to placebo (OR 2.87, 95%CI 0.75-11.04) or to other vasodilatory β-blockers (OR 2.15, 95%CI 0.6-7.77).

CONCLUSION

All antihypertensive medication classes seem to exert neutral or insignificant effects on EF. Further high-quality studies are needed to better explore the effects of antihypertensive medication on EF.

Hypertension and reproductive dysfunction: a possible role of inflammation and inflammation-associated lymphangiogenesis in gonads

Hypertension is one of the most prevalent diseases that leads to end organ damage especially affecting the heart, kidney, brain, and eyes. Numerous studies have evaluated the association between hypertension and impaired sexual health, in both men and women. The detrimental effects of hypertension in men includes erectile dysfunction, decrease in semen volume, sperm count and motility, and abnormal sperm morphology. Similarly, hypertensive females exhibit decreased vaginal lubrication, reduced orgasm, and several complications in pregnancy leading to fetal and maternal morbidity and mortality. The adverse effect of hypertension on male and female fertility is attributed to hormonal imbalance and changes in the gonadal vasculature. However, mechanistic studies investigating the impact of hypertension on gonads in more detail on a molecular basis remain scarce. Hence, the aim of the current review is to address and summarize the effects of hypertension on reproductive health, and highlight the importance of research on the effects of hypertension on gonadal inflammation and lymphatics.

Erectile dysfunction and adherence to antihypertensive therapy: Focus on β-blockers

The management of arterial hypertension is very challenging in everyday clinical practice. Blood pressure control rates remain disappointingly low, despite intense efforts. Poor adherence to antihypertensive treatment is among the main causes of inadequate blood pressure control. Among the various parameters leading to poor adherence, medication adverse events seem to be the prevailing cause of treatment discontinuation. Β-blockers are a class of drugs commonly used in the management of hypertension. However, β-blockers use has been associated with various adverse events, among which, erectile dysfunction is a prevalent one. Accumulating evidence supports the detrimental role of β-blockers on erectile function. Older studies have shown contradictory findings, which however may be attributed to methodological errors related with the assessment of erectile function. More recent studies, however, unveiled the negative impact of this drug category on erectile function. Nevertheless, β-blockers represent a class of drugs with substantial within class heterogeneity. Nebivolol presents a unique mode of action through enhanced nitric oxide bioavailability that may be associated with benefits on erectile function. Indeed, studies of nebivolol have shown improvement in erectile function, suggesting that nebivolol represents the only exception in this class of drugs in terms of erectile function.

Efficacy and safety of nebivolol in hypertensive patients: a meta-analysis of randomized controlled trials

Purpose

Our meta-analysis was undertaken to evaluate the efficacy and safety of nebivolol compared with other second-generation β blockers for hypertensive patients.

Methods

We searched PubMed, the Cochrane Library, EMBASE, and Clinical Trials.gov databases for randomized controlled trials (RCTs). The efficacy endpoints included systolic blood pressure (SBP), diastolic blood pressure (DBP), reduction of SBP and DBP, heart rate (HR), and adverse events (AEs).

Findings

Eight RCTs with 1514 patients met the inclusion criteria. HR was significantly lower in patients receiving other second-generation β blockers compared with patients receiving nebivolol. There was no difference the reduction of blood pressure (SBP and DBP) or the reduction of SBP or DBP between the groups. The incidence of AEs was lower in patients taking nebivolol compared with patients taking other second-generation β blockers.

Conclusions

No significant difference was demonstrated between nebivolol and other second-generation β blockers in the reduction of blood pressure, SBP, and DBP. The tolerability of nebivolol was significantly better compared with other second-generation β blockers, and nebivolol was also associated with a stable HR and a lower risk of AEs compared with other second-generation β blockers.

The physiology of male reproduction: Impact of drugs and their abuse on male fertility

Male factor accounts for about 30-50% of infertility. A common cause of male infertility is drug abuse; either illicit or prolonged use of prescribed drugs. This study provides a review of the physiology of the hypothalamic-pituitary-gonadal axis and recent literature on drugs that have been linked to male infertility and the associated mechanisms. Relevant peer-reviewed papers were assessed online using PubMed/PubMed Central, Scopus, AJOL, Google Scholar and DOAJ databases using Medical Subjects Headings (MeSH) indexes and relevant key word searches. Although drugs are beneficial when used at therapeutic levels, the abuse leads to impairment of hypothalamic-pituitary-gonadal functions, increased sperm DNA fragmentation and apoptosis, and reduced sperm quality. A good knowledge of the physiology of the hypothalamic-pituitary-gonadal axis and the influence of drugs on male fertility will guide healthcare providers in managing cases of infertility.

[Sexual dysfunction and antihypertensive treatment: Involvement of the different therapeutic classes and what to do about the treatment of hypertension]

Erectile dysfunction (ED) is not routinely discussed with patients in cardiology practices whereas it may impact the ability of patients to stay on therapy. Most of the studies about ED and antihypertensive therapies have several methodological limitations. Diuretics and beta-blockers have been shown to have a deleterious effect on ED. ISRA inhibitors, calcium antagonists, vasodilator beta-blockers and alpha-blockers have been shown to have a neutral impact on ED. Angiotensin 2 inhibitors, nebivolol and alpha-blockers use has sometimes beneficial effect on ED. In case of ED due to antihypertensive treatment, drugs can be switched each other but careful attention in patients with a high cardiovascular risk is required.

In vitro evaluation of nebivolol effects on nonadrenergic noncholinergic responses in rabbit corpus cavernosum

The purpose of this study was to compare the effects of nebivolol on nonadrenergic noncholinergic (NANC) relaxation functions that are mediated by electric field stimulation (EFS) in rabbit corpus cavernosum smooth muscle by comparison with other beta-adrenergic receptor blockers and show the level on which its effects through nitric oxide take place. After the effects of nebivolol on the isolated corpus cavernosum tissues that were contracted through the alpha-adrenergic pathway and application of L-NAME' (N^G -nitro-L-arginine methyl ester) which is a competitive inhibitor of nitric oxide synthase (NOS), the changes that occurred were recorded. Following the effect on the tissue that was contracted with phenylephrine in the presence of atropine and guanethidine that was created by EFS, nebivolol and other beta-blockers were added and the changes were recorded. After receiving relaxation responses with EFS-mediated NANC, no difference was observed between the relaxation responses due to addition of nebivolol and other beta-adrenergic blockers (p > 0.05). The finding that nebivolol which has a NO-mediated relaxation effect did not have an effect on EFS-mediated NANC relaxation but created relaxation on the tissue that was contracted by phenylephrine and the effect was reversed by L-NAME, shows that its effects are on a postsynaptic level.

Sexual Activity in Patients with Cardiac Diseases

SUMMARY – In this article, we outline the latest guidelines published by the American Heart Association on sexual activity in patients with coronary artery disease, heart failure, structural heart diseases, arrhythmias, implanted pacemakers or cardioverter defibrillators, as well as on treatment options of sexual dysfunction. Sexual activities are similar to mild/moderate physical activity during a short period. Most patients are recommended to involve in sexual activity after prior comprehensive evaluation of physical condition. Those with stable cardiac symptoms and good functional capacity are at a low risk of adverse cardiovascular events, and others require treatment or stabilization before involving in sexual activity. Stress testing is useful in evaluating safety of sexual activity in patients with questionable or undetermined risk. Treatment of sexual dysfunction includes counseling of patients and their sexual partners, and drug treatment with phosphodiesterase inhibitors (sildenafil, tadalafil, vardenafil) which have been demonstrated to be safe and effective, in men, and with serotonin reuptake inhibitors (flibanserin) and local vaginal estrogen administration in women. In conclusion, in routine clinical practice, patients should be approached individually and multidisciplinarily in order to detect and eliminate the factors that interfere with normal sexual activities and disturb the quality of life.

Erectile Dysfunction and Ischaemic Heart Disease

Erectile dysfunction (ED) is a common disorder that affects the quality of life of many patients. It is prevalent in more than half of males aged over 60 years. Increasing evidence suggests that ED is predominantly a vascular disorder. Endothelial dysfunction seems to be the common pathological process causing ED. Many common risk factors for atherosclerosis such as diabetes, hypertension, smoking, obesity and hyperlipidaemia are prevalent in patients with ED and so management of these common cardiovascular risk factors can potentially prevent ED. Phosphodiesterase type 5 inhibitors provide short-term change of haemodynamic factors to help initiate and maintain penile erection. They have been shown to be an effective and safe treatment strategy for ED in patients with heart disease, including those with ischaemic heart disease and hypertension.

The impact of drugs on male fertility: a review

Beside cytotoxic drugs, other drugs can impact men's fertility through various mechanisms. Via the modification of the hypothalamic-pituitary-gonadal axis hormones or by non-hormonal mechanisms, drugs may directly and indirectly induce sexual dysfunction and spermatogenesis impairment and alteration of epididymal maturation. This systematic literature review summarizes existing data about the negative impact and associations of pharmacological treatments on male fertility (excluding cytotoxic drugs), with a view to making these data more readily available for medical staff. In most cases, these effects on spermatogenesis/sperm maturation/sexual function are reversible after the discontinuation of the drug. When a reprotoxic treatment cannot be stopped and/or when the impact on semen parameters/sperm DNA is potentially irreversible (Sulfasalazine Azathioprine, Mycophenolate mofetil and Methotrexate), the cryopreservation of spermatozoa before treatment must be proposed. Deleterious impacts on fertility of drugs with very good or good level of evidence (Testosterone, Sulfasalazine, Anabolic steroids, Cyproterone acetate, Opioids, Tramadol, GhRH analogues and Sartan) are developed.

The Comparison of the Effects of Nebivolol and Metoprolol on Erectile Dysfunction in the Cases with Coronary Artery Bypass Surgery

PURPOSE

Beta-blocker use is common in the cases with coronary artery bypass surgery. According to the literature, beta-blockers have positive effects but may cause erectile dysfunction (ED). The most commonly used beta-blockers in ischemic cardiac disease are nebivolol and metoprolol. In our clinic, we aimed to compare the effects of nebivolol and metoprolol succinate on ED in the sexually active cases with coronary artery bypass surgery.

METHODS

In our clinic, a total of 119 patients with coronary artery bypass surgery were included in the study. International Index of Erectile Function (IIEF-5) Test was used to evaluate whether the patients had ED and to grade the cases.

RESULTS

No significant difference was found in terms of anti-ischemic efficacy between metoprolol succinate and nebivolol in the postoperative period; however, the incidence of any grade ED was %85.96 in Group 1, %83.87 in Group 2. This difference was considered as statistically significant (p = 0.036).

CONCLUSION

Beta-blocker use increases the risk of ED in cases with ischemic cardiac disease. We suggest that the complaints of ED could be less frequent with nebivolol use in sexually active cases with ischemic cardiac disease.

Nebivolol versus other beta blockers in patients with hypertension and erectile dysfunction

Erectile dysfunction (ED) impacts over 100 million men worldwide and occurs at a higher incidence in men with hypertension. Beta blockers are one of several antihypertensive drug classes associated with ED. Nebivolol is a beta blocker with vasodilating properties mediated through endothelial release of nitric oxide which facilitates penile erection. Thus, nebivolol may offer an advantage over other beta blockers in the patient with hypertension and ED. A literature search comparing nebivolol with other beta blockers identified four European studies of limited duration, with the longest study being 28 weeks. Survey scores for erectile function showed significant improvement in erectile function with nebivolol in two of the studies, while the other two studies showed erectile function did not significantly worsen with nebivolol as compared with other beta blocker agents. One study showed improved erectile function scores, possibly due to the presence of a Hawthorne effect. Based on this small sample of studies, nebivolol may be of use in the patient with or at risk of developing ED, when a practitioner specifically wants to use a beta blocker as add-on antihypertensive treatment.

Antihypertensive therapy causes erectile dysfunction

PURPOSE OF REVIEW

Erectile dysfunction is a common sexual disorder affecting 40% of men in the United States. However, the pathophysiologic mechanism involved in the causation of erectile dysfunction is multifactorial and not well delineated.

RECENT FINDINGS

Several recent studies disclose that erectile dysfunction is the result of multiple interrelated comorbid conditions that include hypertension, coronary artery disease (CAD), heart failure, and diabetes mellitus among them. In addition to comorbid conditions, certain cardiovascular and antihypertensive drugs are also involved in the development of erectile dysfunction, with the most prominent being the thiazide type diuretics, the aldosterone receptor blockers, and the β-adrenergic receptor blockers. Also, knowledge by the patient of the drug and its action on erectile dysfunction may increase the incidence of erectile dysfunction (Hawthorn effect). Before treatment is initiated, patients should be screened for the presence of erectile dysfunction, because this condition is associated with hypertension, CAD, heart failure, diabetes mellitus, and their treatment and an appropriate treatment regimen should be selected. If that fails, the addition of phosphodiesterase 5 inhibitors to the treatment regimen is recommended. The only exception is a patient with CAD treated with organic nitrates, in which the coadministration of phosphodiesterase 5 inhibitors is strictly prohibited.

SUMMARY

Knowledge of the various comorbid conditions and their treatment associated with the development of erectile dysfunction will help the caring physician to treat his patients appropriately and safely. All these aspects will be discussed in this review.

A Review of Nebivolol Pharmacology and Clinical Evidence

Nebivolol is a highly selective β1-adrenergic receptor antagonist with a pharmacologic profile that differs from those of other drugs in its class. In addition to cardioselectivity mediated via β1 receptor blockade, nebivolol induces nitric oxide-mediated vasodilation by stimulating endothelial nitric oxide synthase via β3 agonism. This vasodilatory mechanism is distinct from those of other vasodilatory β-blockers (carvedilol, labetalol), which are mediated via α-adrenergic receptor blockade. Nebivolol is approved for the treatment of hypertension in the US, and for hypertension and heart failure in Europe. While β-blockers are not recommended within the current US guidelines as first-line therapy for treatment of essential hypertension, nebivolol has shown comparable efficacy to currently recommended therapies in lowering peripheral blood pressure in adults with hypertension with a very low rate of side effects. Nebivolol also has beneficial effects on central blood pressure compared with other β-blockers. Clinical data also suggest that nebivolol may be useful in patients who have experienced erectile dysfunction while on other β-blockers. Here we review the pharmacological profile of nebivolol, the clinical evidence supporting its use in hypertension as monotherapy, add-on, and combination therapy, and the data demonstrating its positive effects on heart failure and endothelial dysfunction.

Nebivolol compared with metoprolol for erectile function in males undergoing coronary artery bypass graft

OBJECTIVE

The aim of this study was to evaluate erectile function in males undergoing coronary artery bypass graft (CABG) while on two different adrenoceptor beta-blocker regimens, namely nebivolol and metoprolol. We hypothesize that the negative effects of cardiopulmonary bypass on erectile function may be possibly attenuated by preferring a vasodilating selective β1-blocker, nebivolol, to metoprolol as an anti-ischemic and antiarrhythmic agent in males undergoing CABG.

METHODS

This randomized, double-blind, prospective clinical study was conducted in patients scheduled for CABG surgery between February 2012 and June 2014. A total of 60 consecutive patients who met inclusion criteria were randomized and divided into the following two groups: N group, which received 5 mg of nebivolol orally for 2 weeks before surgery plus 12 weeks after surgery or M group, which received 50 mg of metoprolol orally for the same period. All patients were evaluated by the erectile function domain of the International Index of Erectile Function-5 (IIEF-5) at the time of admission (before starting the beta-blocker) and 3 months after surgery.

RESULTS

In the metoprolol group, the mean IIEF-5 score decreased significantly from a baseline of 15.2±5.8 to 12.9±5.8 (p<0.001), but in the nebivolol group, this difference was not significant (from a baseline 12.9±5.5 to 12.4±5.5, p=0.053). In all patients, the mean IIEF-5 score decreased significantly from a baseline of 14.0±5.7 to 12.6±5.6 (p<0.001).

CONCLUSION

Although erectile function in males undergoing CABG surgery decreases when metoprolol is used, nebivolol exerts protective effects on erectile function against the disruptive effects of cardiopulmonary bypass in patients undergoing CABG.

Clinical utility of fixed-dose combinations in hypertension: evidence for the potential of nebivolol/valsartan

Despite significant advances in pharmacologic approaches to treat hypertension during the last decades, hypertension- and hypertension-related organ damage are still a high health and economic burden because a large proportion of patients with hypertension do not achieve optimal blood pressure control. There is now general agreement that combination therapy with two or more antihypertensive drugs is required for targeted blood pressure accomplishment and reduction of global cardiovascular risk. The goals of combination therapies are to reduce long-term cardiovascular events by targeting different mechanism underlying hypertension and target organ disease, to block the counterregulatory pathways activated by monotherapies, to improve tolerability and decrease the adverse effects of up-titrated single agents, and to increase persistence and adherence with antihypertensive therapy. Multiple clinical trials provide evidence that fixed-dose combinations in a single pill offer several advantages when compared with loose-dose combinations. This review discusses the advances in hypertension control and associated cardiovascular disease as they relate to the prospect of combination therapy targeting a third-generation beta (β) 1-adrenergic receptor (nebivolol) and an angiotensin II receptor blocker (valsartan) in fixed-dose single-pill formulations.

Nebivolol potentiates the efficacy of PDE5 inhibitors to relax corpus cavernosum and penile arteries from diabetic patients by enhancing the NO/cGMP pathway

INTRODUCTION

The efficacy of oral pharmacotherapy for erectile dysfunction (ED) (i.e., type 5 phosphodiesterase[PDE5] inhibitors) is significantly reduced in diabetic patients. Nebivolol is a selective β1-blocker used for treatinghy pertension that has been shown to increase the efficacy of sildenafil to reverse ED in diabetic rats.

AIM

To evaluate the effects of nebivolol on the efficacy of the PDE5 inhibitors, sildenafil, tadalafil, and vardenafil to relax human corpus cavernosum (HCC) and vasodilate human penile resistance arteries (HPRA) from diabetic patients with ED (DMED). The influence of nebivolol on the capacity of these three PDE5 inhibitors to stimulate cyclic guanosine monophosphate (cGMP) production in HCC was also evaluated.

METHODS

HCC and HPRA were obtained from organ donors without ED (NEND; n = 18) or patients with diabetes undergoing penile prosthesis implantation (DMED; n = 19). Relaxations of HCC strips and HPRA to sildenafil,tadalafil, and vardenafil were evaluated in organ chambers and wire myographs. cGMP content in HCC was determined by ether extraction and quantification by ELISA.

MAIN OUTCOME MEASURES

Effects of nebivolol on PDE5 inhibitor-induced relaxation of HCC, vasodilation ofHPRA and cGMP accumulation in HCC.

RESULTS

Treatment with nebivolol (1 μM) significantly potentiated sildenafil-, tadalafil- and vardenafil-induced relaxations of HCC and vasodilations of HPRA from both NEND and DMED. Enhancement of relaxant capacity by nebivolol resulted in reversion of the impairment of PDE5 inhibition-induced responses in DMED and it was accompanied by enhancing the ability of PDE5 inhibitors to increase cGMP in HCC restoring reduced cGMP levelsin HCC from DMED.

CONCLUSIONS

Nebivolol potentiated the capacity of PDE5 inhibitors to relax vascular structures of erectile tissue from diabetic patients by enhancing the nitric oxide (NO)/cGMP pathway in these tissues. These effects suggest a potential therapeutic utility of nebivolol as an adjunct to PDE5 inhibitors for the treatment of ED associated with diabetes.

The influence of new beta-adrenolytics nebivolol and carvedilol on intraocular pressure and iris blood flow in rabbits

BACKGROUND

The aim of this study was to assess the influence of propranolol, nebivolol, and carvedilol on intraocular pressure and blood flow in vessels of rabbit's (New Zealand White) eyeball.

METHODS

The study was carried out on New Zealand white rabbits. Intraocular pressure was measured with the applanation tonometer Möller-Wedel and Icare; blood flow was measured with Doppler Laser Blood Flow Monitor MBD3.

RESULTS

Following a single administration into a conjunctival sac, all drugs decreased intraocular pressure. Iris blood flow was decreased following administration of propranol, but increased by nebivolol and carvedilol. After single and repeated oral administration of nebivolol and carvedilol an IOP decrease was demonstrated, but with no effect of all applied doses on iris or retina/choroid blood flow.

CONCLUSION

Studies performed on an animal model indicate that it is possible to reduce the intraocular pressure and increase ocular blood flow in humans, following topical administration of carvedilol and nebivolol. Confirmation of those results in clinical trials may lead to development of a new anti-glaucoma treatment. Further clinical studies of long-term nebivolol and carvedilol are recommended. They are necessary for evaluation of usefulness of those drugs for selected groups of patients, for example those with glaucoma and arterial hypertension.

Nebivolol: vasodilator properties and evidence for relevance in treatment of cardiovascular disease

β-adrenergic blocking agents, a pharmacologically diverse class of cardiovascular medications, are recommended as first-line treatment for patients with hypertension and concomitant structural heart disease, and for angina and heart failure. Many within-class differences exist, from pharmacokinetics and pharmacodynamics to ancillary effects, such as intrinsic sympathomimetic activity, antiarrhythmic activity, α-1 adrenergic receptor blockade affinity, and direct vasodilation. Nebivolol is a third-generation, β1 selective, long acting β-blocker, which causes direct vasodilation via endothelium-dependent nitric oxide stimulation. The vasodilatory actions of nebivolol might result in clinical effects with some distinct properties. Differences from other β-blockers might include improvement of endothelial function, enhancement of forward flow in muscular resistance arteries, maintenance of exercise tolerance, and overall improved tolerability, side effect profile, and adherence. Nebivolol has been shown to be a clinically effective β-blocker for treatment as initial or add-on therapy for systemic hypertension, as an antianginal agent, and as therapy for patients with heart failure. These properties position nebivolol as a treatment option for patients with hypertension and/or structural heart disease, although its precise role in the therapeutic armamentarium remains to be clarified.

Sexual function in patients with chronic angina pectoris

Drugs for erectile dysfunction (ED) may be contraindicated with nitrates commonly used to treat patients with angina pectoris, and certain antianginal therapies may worsen ED. The American Heart Association and the Princeton Consensus Conference panel of experts recommend that patients with coronary artery disease and ED who experience angina pectoris undergo full medical evaluations to assess the cardiovascular risks associated with resuming sexual activity before being prescribed therapy for ED. Current antianginal therapies include β blockers, calcium channel blockers, short- and long-acting nitrates, and ranolazine, a late sodium current inhibitor. Short- and long-acting nitrates remain a contraindication with phosphodiesterase-5 inhibitors commonly used to treat patients with ED, and the benefits of the other antianginal therapies must be weighed against their effects on cardiovascular health and erectile function. In conclusion, patients with coronary artery disease and ED who wish to initiate phosphodiesterase-5 inhibitor therapy and need to discontinue nitrate therapy need treatment options that manage their angina pectoris effectively, maintain their cardiovascular health, and provide the freedom to maintain their sexual function.

The Princeton III Consensus recommendations for the management of erectile dysfunction and cardiovascular disease

The Princeton Consensus (Expert Panel) Conference is a multispecialty collaborative tradition dedicated to optimizing sexual function and preserving cardiovascular health. The third Princeton Consensus met November 8 to 10, 2010, and had 2 primary objectives. The first objective focused on the evaluation and management of cardiovascular risk in men with erectile dysfunction (ED) and no known cardiovascular disease (CVD), with particular emphasis on identification of men with ED who may require additional cardiologic work-up. The second objective focused on reevaluation and modification of previous recommendations for evaluation of cardiac risk associated with sexual activity in men with known CVD. The Panel's recommendations build on those developed during the first and second Princeton Consensus Conferences, first emphasizing the use of exercise ability and stress testing to ensure that each man's cardiovascular health is consistent with the physical demands of sexual activity before prescribing treatment for ED, and second highlighting the link between ED and CVD, which may be asymptomatic and may benefit from cardiovascular risk reduction.

Efficacy and tolerability of nebivolol: does age matter? A retrospective analysis of three randomized, placebo-controlled trials in stage I-II hypertension

OBJECTIVES

This retrospective analysis examined the efficacy and tolerability of nebivolol, a ß(1)-selective, vasodilatory β-blocker, in four different age groups of patients with hypertension.

METHODS

Data were pooled from three 12-week, randomized, placebo-controlled trials (placebo, n = 205; nebivolol [1.25-30/40 mg/day], n = 1811) and stratified into age quartiles (Group 1: 22-46 years; Group 2: 47-53 years; Group 3: 54-62 years; Group 4: 63-84 years). Only patients treated with placebo and the three commonly used nebivolol dosages (5, 10, and 20 mg/day) are presented. Baseline-to-endpoint changes in trough sitting diastolic blood pressure (DBP), systolic blood pressure (SBP), and heart rate (HR) were analyzed for each age quartile using an analysis of covariance (ANCOVA) model. Tolerability was assessed by means of adverse event (AE) rates.

RESULTS

The analysis comprised 205 placebo-treated patients and 1380 patients treated with nebivolol dosages of 5, 10, or 20 mg/day. Older age was associated with higher SBP values at baseline. In all age groups, each of the three most frequently used nebivolol dosages significantly reduced DBP, compared with placebo (-9.1 to -11.8 mmHg versus -3.4 to -5.9 mmHg; p ≤ 0.008 overall). For SBP, a statistically significant effect versus placebo was observed for all dosages and age groups except for 5 and 10 mg/day in Group 4. Within each group, treatment with nebivolol (all three dosages) and placebo resulted in similar AE rates (nebivolol: 26.1-36.6%; placebo: 36.2-42.6%) and AE-related discontinuation rates (1.8-3.8% versus 0-4.3%). In each age group, there were no significant nebivolol-placebo differences in the rates of patients who experienced clinically significant changes or abnormal endpoint levels of metabolic parameters.

CONCLUSIONS

This retrospective analysis suggests that nebivolol monotherapy is efficacious and well tolerated across various age groups, with the efficacy in reducing SBP somewhat diminishing in patients over 62 years of age.

The Princeton III Consensus recommendations for the management of erectile dysfunction and cardiovascular disease

The Princeton Consensus (Expert Panel) Conference is a multispecialty collaborative tradition dedicated to optimizing sexual function and preserving cardiovascular health. The third Princeton Consensus met November 8 to 10, 2010, and had 2 primary objectives. The first objective focused on the evaluation and management of cardiovascular risk in men with erectile dysfunction (ED) and no known cardiovascular disease (CVD), with particular emphasis on identification of men with ED who may require additional cardiologic work-up. The second objective focused on reevaluation and modification of previous recommendations for evaluation of cardiac risk associated with sexual activity in men with known CVD. The Panel's recommendations build on those developed during the first and second Princeton Consensus Conferences, first emphasizing the use of exercise ability and stress testing to ensure that each man's cardiovascular health is consistent with the physical demands of sexual activity before prescribing treatment for ED, and second highlighting the link between ED and CVD, which may be asymptomatic and may benefit from cardiovascular risk reduction.

The role of nitric oxide in improving endothelial function andcardiovascular health: focus on nebivolol

Although β-blockers have been endorsed by guidelines committees for the treatment of patients with hypertension, particularly those with significant CVD and high CVD risk, there are concerns about conventional β-blockers related to poorer clinical outcomes compared with other classes of antihypertensive agents, as well as deleterious effects on quality of life and lipid and carbohydrate metabolism. β-blockers comprise a heterogeneous group of antihypertensive agents, including nonselective agents, cardioselective, nonvasodilating agents, and vasodilating agents that either combine β-nonselectivity with β-blockade or possess cardioselectivity without β-blockade. The pharmacologic, mechanistic, and hemodynamic differences between conventional, nonvasodilating β-blockers and vasodilating β-blockers are discussed in this review, with a focus on the cardioselective vasodilating β-blocker nebivolol. These differences may have important clinical implications, particularly in the treatment of complicated hypertension, such as that associated with patients with diabetes or cardiometabolic syndrome, elderly patients, and African American patients, suggesting that mechanism of action may be an important consideration when choosing a β-blocker.

Cardiovascular risk, drugs and erectile function--a systematic analysis

AIMS

Erectile dysfunction is a major problem with an increasing prevalence in cardiovascular high-risk patients due to its association with cardiovascular risk factors. Drugs used for evidence-based treatment of cardiovascular diseases have been reported to decrease erectile function, but possible mechanisms are poorly characterised.

METHODS

MEDLINE, EMBASE and Cochrane Registry search were performed including manuscripts until January 2010. Searching terms are: 'erectile dysfunction or impotence' in combination with 'ACE-inhibitors', 'angiotensin', 'beta-blockers', 'calcium antagonist' and 'diuretics'. Animal studies, letters, reviews, case-reports and manuscripts other than English language and trials dealing with combination treatment are excluded.

RESULTS

Analysis of literature revealed five epidemiological trials evaluating the effect of different cardiovascular drugs on erectile function. There were eight trials evaluating the effect of beta-blockers, five trials evaluating the effect of ace-inhibitors or angiotensin-receptor-blockers and one trial evaluating the effect of diuretics on erectile function. Results of these trials demonstrate that only thiazide diuretics and beta-blockers except nebivolol may adversely influence erectile function. ACE-inhibitors, angiotensin-receptor-blockers and calcium-channel-blockers are reported to have no relevant or even a positive effect on erectile function.

CONCLUSION

Inappropriate patients' concerns about adverse effects of cardiovascular drugs on erectile function might limit the use of important medications in cardiovascular high-risk patients. Knowledge about the effects of drug-treatments on erectile function and about the major role of the endothelium in penile function might improve patients' adherence to evidence based treatment of cardiovascular diseases.

A comparative study of nebivolol and (S) atenolol on blood pressure and heart rate on essential hypertensive patients

Objectives:

To study the effect of nebivolol 5 mg once daily versus (S)-atenolol 25 mg once daily in patients with essential hypertension.

Materials and Methods:

A prospective study was conducted at RLJH and Research Centre which included 30 patients in each group with essential hypertension. The sex, age, presenting illness, and family history of the patients were recorded. Investigations such as blood sugar, urine analysis, kidney function test, lipid profile, and ECG were performed before starting the treatment. Any adverse effects during the treatment were noted. Blood pressure and heart rate were recorded at baseline and during follow-up. One group received nebivolol 5 mg once daily and other group (S)atenolol 25 mg once daily. Patients were followed-up every 15 days for 3 months.

Results:

Nebivolol group had 18 males and 12 females with mean age 50.6 ± 9.5 years, (S)-atenolol had 16 males and 14 females with mean age 54.4 ± 9 years. Patients receiving nebivolol and (S)-atenolol showed a significant fall (P <·0001) in systolic (SBP), diastolic blood pressure (DBP), and heart rate at the end of first, second, and third month when compared to baseline. The difference in fall in SBP and DBP was insignificant between the groups, but fall in heart rate was significant (P <·0001). Adverse effects such as headache, dizziness, and fatigue were reported with both drugs.

Conclusion:

Reduction of blood pressure with nebivolol and (S)atenolol was similar, but fall in blood pressure from baseline was highly significant in both groups.

[Sexual dysfunction in the elderly. Pathophysiological and medical issues. Treatment of erectile dysfunction]

Erectile dysfunction (ED) is a very distressing condition that not only negatively affects the elderly man's sexual ability, but also his overall quality of life and that of his partner. Encouraging men, alone or as a couple, to seek professional help is a major educational challenge which needs to be met by medical, social and political initiatives. The exact pathogenesis of ED remains unknown, but is presumed to be multifactorial; vascular disease is the most frequent cause with endothelial dysfunction being the common denominator. It has been postulated that ED is a sentinel symptom of cardiovascular clinical events and should prompt investigation and intervention for cardiovascular risk factors. Therefore, when a patient presents with ED, a thorough history and physical examination should be performed, as well as appropriate laboratory tests aimed at detecting associated diseases.

The role of nitric oxide in improving endothelial function and cardiovascular health: focus on nebivolol

Although beta-blockers have been endorsed by guidelines committees for the treatment of patients with hypertension, particularly those with significant CVD and high CVD risk, there are concerns about conventional beta-blockers related to poorer clinical outcomes compared with other classes of antihypertensive agents, as well as deleterious effects on quality of life and lipid and carbohydrate metabolism. beta-Blockers comprise a heterogeneous group of antihypertensive agents, including nonselective agents, cardioselective, nonvasodilating agents, and vasodilating agents that either combine beta-nonselectivity with alpha-blockade or possess cardioselectivity without alpha-blockade. The pharmacologic, mechanistic, and hemodynamic differences between conventional, nonvasodilating beta-blockers and vasodilating beta-blockers are discussed in this review, with a focus on the cardioselective vasodilating beta-blocker nebivolol. These differences may have important clinical implications, particularly in the treatment of complicated hypertension, such as that associated with patients with diabetes or the cardiometabolic syndrome, elderly patients, and African American patients, suggesting that mechanism of action may be an important consideration when choosing a beta-blocker.

Anatomy, physiology, and pathophysiology of erectile dysfunction

INTRODUCTION

Significant scientific advances during the past 3 decades have deepened our understanding of the physiology and pathophysiology of penile erection. A critical evaluation of the current state of knowledge is essential to provide perspective for future research and development of new therapies.

AIM

To develop an evidence-based, state-of-the-art consensus report on the anatomy, physiology, and pathophysiology of erectile dysfunction (ED).

METHODS

Consensus process over a period of 16 months, representing the opinions of 12 experts from seven countries.

MAIN OUTCOME MEASURE

Expert opinion was based on the grading of scientific and evidence-based medical literature, internal committee discussion, public presentation, and debate.

RESULTS

ED occurs from multifaceted, complex mechanisms that can involve disruptions in neural, vascular, and hormonal signaling. Research on central neural regulation of penile erection is progressing rapidly with the identification of key neurotransmitters and the association of neural structures with both spinal and supraspinal pathways that regulate sexual function. In parallel to advances in cardiovascular physiology, the most extensive efforts in the physiology of penile erection have focused on elucidating mechanisms that regulate the functions of the endothelium and vascular smooth muscle of the corpus cavernosum. Major health concerns such as atherosclerosis, hyperlipidemia, hypertension, diabetes, and metabolic syndrome (MetS) have become well integrated into the investigation of ED.

CONCLUSIONS

Despite the efficacy of current therapies, they remain insufficient to address growing patient populations, such as those with diabetes and MetS. In addition, increasing awareness of the adverse side effects of commonly prescribed medications on sexual function provides a rationale for developing new treatment strategies that minimize the likelihood of causing sexual dysfunction. Many basic questions with regard to erectile function remain unanswered and further laboratory and clinical studies are necessary.

Nebivolol dilates human penile arteries and reverses erectile dysfunction in diabetic rats through enhancement of nitric oxide signaling

INTRODUCTION

Traditional beta-blockers have sometimes been associated with erectile dysfunction (ED). Nebivolol is a cardioselective β(1)-adrenoceptor antagonist that promotes vasodilation through a nitric oxide (NO)-dependent mechanism.

AIM

We evaluated the effects of nebivolol on the NO/cyclic guanosine monophosphate (cGMP) signaling pathway, on erectile function and dysfunction, and in human penile vascular tissues.

METHODS

Erectile response to cavernosal nerve electrical stimulation in control and diabetes-induced ED rats were evaluated, along with serum nitrite/nitrate (NOx) concentration and plasma/tissue cGMP levels. Endothelium-dependent and sildenafil-induced relaxation of isolated human corpus cavernosum (HCC) and human penile resistance arteries (HPRA) were also determined.

MAIN OUTCOME MEASURES

The effects of nebivolol on erectile function and dysfunction and on NO/cGMP-mediated responses.

RESULTS

Treatment with nebivolol significantly potentiated erectile response in control rats, regardless of its effects on blood pressure. Nebivolol increased NOx and plasma cGMP by 3-fold and 2.75-fold, respectively, and significantly augmented the elevation of plasma cGMP produced by sildenafil. Nebivolol enhanced endothelium-dependent and sildenafil-induced relaxations of HCC tissue, and produced endothelium-dependent vasodilation of HPRA. Nebivolol, but not atenolol, significantly improved erectile response in diabetic rats (51.6%, 53.2%, and 87.1% of response at 3 Hz in nondiabetic rats, for vehicle-treated, atenolol-treated, and nebivolol-treated diabetic rats, respectively); after sildenafil administration, ED was completely reversed in nebivolol-treated diabetic rats (69.6% and 112% for diabetic rats treated with sildenafil and nebivolol plus sildenafil, respectively). Accordingly, nebivolol restored systemic NOx levels and cGMP content in penile tissue from these animals.

CONCLUSIONS

Nebivolol in vivo activated the NO/cGMP pathway, enhanced erectile response and reversed ED in diabetic rats. Moreover, nebivolol in vitro potentiated NO/cGMP-mediated relaxation of human erectile tissues. These effects may account for the low incidence of ED in nebivolol-treated hypertensive patients. Nebivolol therefore may have utility in the treatment of ED, particularly ED associated with diabetes.

Nebivolol: the somewhat-different beta-adrenergic receptor blocker

Although its clinical use in Europe dates almost 10 years, nebivolol is a beta-blocker that has been only recently introduced in the U.S. market. Like carvedilol, nebivolol belongs to the third generation of beta-blockers, which possess direct vasodilator properties in addition to their adrenergic blocking characteristics. Nebivolol has the highest beta(1)-receptor affinity among beta-blockers and, most interestingly, it substantially improves endothelial dysfunction via its strong stimulatory effects on the activity of the endothelial nitric oxide synthase and via its antioxidative properties. Because impaired endothelial activity is attributed a major causal role in the pathophysiology of hypertension, coronary artery disease, and congestive heart failure, the endothelium-agonistic properties of nebivolol suggest that this drug might provide additional benefit beyond beta-receptor blockade. Although lesser beta-blocker-related side effects have been reported in patients with chronic obstructive pulmonary disease or impotence taking nebivolol, side effects and contraindications overlap those of other beta-blockers. Clinically, this compound has been proven to have antihypertensive and anti-ischemic effects as well as beneficial effects on hemodynamics and prognosis in patients with chronic congestive heart failure. Further studies are now necessary to compare the benefit of nebivolol with that of other drugs in the same class and, most importantly, its prognostic impact in patients with hypertension.

Realities of newer beta-blockers for the management of hypertension

Beta-blockers are prescribed for a variety of cardiovascular conditions including hypertension, heart failure, primary treatment of myocardial infarction (MI), and secondary prevention of ischemic cardiac events. Yet they remain underprescribed in populations at increased risk for cardiovascular disease because of tolerability and safety concerns. Beta-blockers are heterogeneous with respect to pharmacokinetic and pharmacodynamic effects. "Original" agents were nonselective, blocking both beta1-adrenoceptors and beta2-adrenoceptors. Later, new agents were developed with selectivity for beta1-adrenoceptors, and were subsequently followed by beta-blockers, which exhibit additional effects, such as vasodilation. Among newer agents, labetalol, carvedilol, and nebivolol have been approved for use in the United States. Nebivolol possesses both beta1-selectivity and nitric oxide-mediated vasodilatory effects, while carvedilol has attractive effects on insulin resistance and exhibits antioxidant effects. Newer beta-blockers may overcome concerns about efficacy, adverse effects, and tolerability, while delivering cardiovascular protection.

Nitric oxide mechanisms of nebivolol

β-blockers are among the most widely used drugs in the prevention and treatment of cardiovascular disease, although they are associated with increased peripheral resistance. Third-generation β-blockers avoid this adverse effect by inducing vasodilation through different mechanisms. In particular, nebivolol, a highly selective blocker of β1-adrenergic receptors, is the only β-blocker known to induce vascular production of nitric oxide, the main endothelial vasodilator. The specific mechanism of nebivolol is particularly relevant in hypertension, where nitric oxide dysfunction occurs. Indeed, nebivolol is able to reverse endothelial dysfunction. Nebivolol induces nitric oxide production via activation of β3-adrenergic receptors, which can explain the good metabolic profile observed after treatment with this drug. Moreover, nebivolol can also stimulate the β3-adrenergic receptor-mediated production of nitric oxide in the heart, and this stimulation can result in a greater protection against heart failure. In conclusion, nebivolol has a unique profile among antihypertensive drugs, adding to a very high selectivity against β1 adrenergic receptors, and an agonist action on β3 receptors and nitric oxide (NO), which has led to clinically significant improvements in hypertensive patients.