Cardiovascular events in users of sildenafil: results from first phase of prescription event monitoring in England

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.

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.

Everything you ever wanted to know about phosphodiesterase 5 inhibitors and the heart (but never dared ask): How do they work?

INTRODUCTION

Phosphodiesterase 5 inhibitors (PDE5i) were developed while investigating novel treatments for coronary artery disease, but their andrological side effects shifted their indication toward the management of erectile dysfunction. Although PDE5i are now also indicated for pulmonary arterial hypertension and there are mounting preclinical and clinical evidences about their potentially beneficial cardiac effects, their use remains controversial and the involved mechanisms remain unclear.

MATERIALS AND METHODS

This review aimed to analyze the effects of PDE5i administration in various animal and humans models of cardiovascular diseases.

RESULTS

Animal studies have shown that PDE5i have protective effects in several models of cardiac disease. In humans, some studies showed that PDE5i improves microvascular and endothelial dysfunction and exerts positive effects in different samples of cardiovascular (CV) impairment. In contrast, other studies found no benefit (and no harm) in heart failure with preserved ejection fraction. The discrepancies in these findings are likely related to the fact that the mechanisms targeted by PDE5i in human disease are still poorly understood and the target population not yet identified. The mechanisms of actions herein reviewed suggest that hypertrophy, microvascular impairment, and inflammation, should be variably present for PDE5i to work. All these conditions frequently coexist in diabetes. A gender responsiveness has also been recently proposed.

CONCLUSIONS

Continuous PDE5 inhibition may exert cardioprotective effects, improving endothelial function and counteracting cardiac remodeling in some but not all conditions. A better patient selection could help to clarify the controversies on PDE5i use for CV disorders.

Erectile dysfunction and its management in patients with diabetes mellitus

Diabetes can be described as a syndrome of multiple closely related conditions induced by a chronic state of hyperglycaemia resulting from defective insulin secretion, insulin action or both. Chronic complications associated with diabetes (including neuropathy, vascular disease, nephropathy and retinopathy) are common, and of these, erectile dysfunction (ED) deserves special attention. ED and its correlation with cardiovascular disease require careful evaluation and appropriate treatment. PDE5 inhibitors (PDE5is) are an important tool for the treatment of ED, with new drugs coming onto the market since the late 90s. This review offers an overview of PDE5is and their use in treating ED in diabetes. We underline the differences between different types of PDE5i, focusing on available doses, duration of action, T ½, side effects and selectivity profiles in relation to patients with diabetes. We also discuss the link between diabetes and ED in presence of various associated cofactors (obesity, hypertension and its pharmacological treatments, atherosclerosis, hyperhomocysteinaemia, neuropathy, nephropathy, hypogonadism and depression). Finally a number of past and ongoing clinical trials on the use of PDE5is in patients with diabetes are presented to offer an overview of the appropriate treatment of ED in this condition.

An unusual adverse effect of sildenafil citrate: acute myocardial infarction in a nitrate-free patient

Myocardial infarction (MI) associated with sildenafil citrate is seen rarely in patients without any history of coronary artery disease. We report a nitrate-free patient with a history of cardiovascular risk factors who developed acute MI after taking sildenafil. A 44-year-old man diagnosed with acute anterior ST segment elevation MI 120 min after self-administration of 150 mg sildenafil was admitted before attempting any sexual intercourse. The coronary angiography revealed 99% occlusion of the left anterior descending artery (LAD) and a bare-metal stent was implanted. He was discharged after 5 days without any complication. Sildenafil may cause coronary steal or may lead to vasodilation causing hypotension in patient with pre-existing cardiovascular disease, especially in patients on nitrate therapy. Our patient was nitrate free, with normal blood pressure values. Emotional stimulation associated with anticipated sexual activity may have been a triggering factor for vulnerable coronary plaque rupture.

Selectivity of avanafil, a PDE5 inhibitor for the treatment of erectile dysfunction: implications for clinical safety and improved tolerability

INTRODUCTION

Phosphodiesterase type 5 (PDE5) inhibitors are indicated for the treatment of erectile dysfunction (ED); however, they can also inhibit other PDE isozymes, affecting their target tissues (e.g., PDE1: heart; PDE6: retina; and PDE11: skeletal muscle), which in some cases can cause unwanted side effects and therapy discontinuation. Data from in vitro studies showed that avanafil, a PDE5 inhibitor for the treatment of ED, exhibited strong selectivity toward PDE5 and against all other PDE isozymes.

AIM

To review the inhibitory effects of avanafil for PDE isozymes compared with those of sildenafil, tadalafil, and vardenafil and to discuss these results within the context of clinical trial safety observations.

METHODS

Review of in vitro selectivity data for avanafil (published primary data from a peer-reviewed journal and scientific congress abstracts); PubMed search for pertinent publications on PDE5 inhibitor safety data; and review of published articles and abstracts from avanafil phase 1, 2, and 3 clinical trials.

MAIN OUTCOME MEASURES

A low incidence of some PDE-related adverse events may be reflected by the high selectivity of avanafil against non-PDE5 isozymes.

RESULTS

Avanafil is highly selective toward PDE5 and against all other PDE isozymes tested. Lower selectivity against PDE1, PDE6, and PDE11 is consistent with results from randomized, placebo-controlled, phase 3 trials in which musculoskeletal and hemodynamic adverse events were reported in <2% of patients and no color vision-related abnormalities were reported with avanafil doses up to 200 mg once daily.

CONCLUSIONS

Data suggest that avanafil may confer a safety benefit, in terms of a lower incidence of specific adverse events, by virtue of its high specificity to PDE5 and its overall selectivity against other PDE isozymes.

Emerging new uses of phosphodiesterase-5 inhibitors in cardiovascular diseases

Phosphodiesterase type-5 (PDE-5) is an enzyme that catalyzes the hydrolytic degradation of cyclic GMP - an essential intracellular second messenger that modulates diverse biological processes in living cells. Three selective inhibitors of PDE-5 - sildenafil, vardenafil and tadalafil - have been successfully used by millions of men worldwide for the treatment of erectile dysfunction. Also, sildenafil and tadalafil are currently approved for the treatment of pulmonary hypertension. Recent powerful basic science data and clinical studies suggest potential nonurological applications of PDE-5 inhibitors, including ischemia/reperfusion injury, myocardial infarction, cardiac hypertrophy, cardiomyopathy, heart failure, stroke, neurodegenerative diseases and other circulatory disorders including Raynaud's phenomenon. Future carefully controlled clinical trials would hopefully expedite their expanding therapeutic use in patients with cardiovascular disease.

Integrating evidence from multiple sources to evaluate post-approval safety: an example of sildenafil citrate and cardiovascular events

OBJECTIVE

Recent high-profile medicine withdrawals have highlighted the complex decision-making process that regulators, pharmaceutical companies, prescribers, and patients must undertake in determining whether a drug has an appropriate benefit-risk balance. Our objective was to analyze the utility of different drug safety data sources and methods, using the experience of sildenafil citrate (Viagra) and post-approval concerns about its potential association with cardiovascular (CV) events (i.e., myocardial infarction [MI] and death) as a case study.

METHODS

We evaluated safety data from three sources: the standard passive surveillance system (i.e., spontaneous reports filed to Pfizer Inc), pooled clinical trial data, and a prospective observational cohort study, the International Men's Health Study (IMHS).

RESULTS

More than 28 000 spontaneous reports were received in the first 7 years after approval. Between 2001 and 2005, the proportion filed by persons other than healthcare professionals (61%) was approximately double the proportion averaged across five other drugs from the manufacturer's safety database. CV events and/or deaths represented 22.0% of reports, and 23% of reported deaths were medically unconfirmed reports made by persons other than healthcare professionals. In contrast, MI and all-cause mortality rates for sildenafil from both the pooled clinical trial data and the IMHS were similar to placebo, despite differences in methods and populations.

CONCLUSIONS

These results suggest that passive surveillance may generate apparent signals of risk, as was the case with sildenafil and CV events. However, to adequately assess the benefit-risk profile of a drug, these signals must be evaluated via other data sources such as clinical trial and epidemiologic studies, as the apparent signal was not supported by more rigorously collected data. Our post-marketing analysis was unable to examine all potential influences of spontaneous reports, and the study data sources (although large for erectile dysfunction studies) were not designed to exclude small CV risks.

Does sildenafil cause myocardial infarction or sudden cardiac death?

Sildenafil was the first oral compound to be approved for the treatment of erectile dysfunction. In this paper, we review the current knowledge of the effects of sildenafil on myocardial infarction and sudden cardiac death. The first factor we examine is the sexual activity itself. As several studies have shown, the relative risk for an acute coronary syndrome during intercourse is not very high. Several studies examining the effects of sildenafil on mortality have been published during recent years. The great majority of these studies found that sildenafil is not an extra risk factor for an acute coronary syndrome or sudden cardiac death. In 1997, the rate of myocardial infarction in men 55-64 years of age was 1542 per 1,000000 in the US. According to this, the expected number of deaths as a result of myocardial infarction in patients 55-64 years of age receiving sildenafil, in the 24-hour period after use, from late March 1997 to mid November 1998, should have been 52. Instead, the number of reported deaths were only 15. One very optimistic finding was that sildenafil not only does not increase mortality, but in fact 'preconditions' the heart and has a cardioprotective effect. Besides, many studies have shown that sildenafil does not reduce the exercise tolerance in men with known coronary artery disease. As far as BP is concerned, the differences before and after the use of sildenafil are not clinically significant. The only contraindications for sildenafil are co-administration with alpha-adrenoceptor antagonists or with nitric oxide donors. According to the most recent studies, isoform 5 of phosphodiesterase has also been detected in the myocardium and controls the soluble pool of 3', 5'-cyclic guanosine monophosphate (cGMP). Sildenafil is very specific for cGMP but it may increase cyclic adenosine monophosphate in the myocardium indirectly. This does not occur with small therapeutic doses of the drug. There is some dispute regarding the association of sildenafil with arrhythmias, where the available evidence is not clear. However, there are suspicions that sildenafil may cause sympathetic activation. The overall conclusion is that sildenafil is a safe drug and that its appropriate use does not seem to increase the risk for myocardial infarction or sudden cardiac death.

Current safety and tolerability issues in men with erectile dysfunction receiving PDE5 inhibitors

AIMS

Treatment of erectile dysfunction (ED) has been greatly advanced by the advent of phosphodiesterase type-5 (PDE5) inhibitors. Upon the introduction of these agents, their cardiovascular (CV) safety was a major concern, mainly due to their vasodilatory effects. We conducted an electronic literature review of data concerning the safety and tolerability issues of men with ED receiving PDE5 inhibitors.

RESULTS

Although safety concerns have been raised, evaluation of CV safety and related adverse events in clinical trials has not revealed any atypical safety issues.

DISCUSSION

No causal association has been established to date between non-arteritic anterior ischaemic optic neuropathy (NAION) and PDE5 inhibitors. In addition, there are established guidelines which provide recommendations for the safe and effective use of these agents in treating men with ED and associated comorbidities.

CONCLUSIONS

Clinical trial and postmarketing surveillance data confirm the safety and tolerability profile of the PDE5 inhibitors, even in patients with endothelial dysfunction-associated comorbidities.

Diagnosis and management of erectile dysfunction in the primary care setting

Recent advances in the management of erectile dysfunction (ED) involve the use of oral phosphodiesterase type-5 (PDE-5) inhibitor therapies which have transformed the perception of ED for both the patient and the healthcare provider. Recent treatment guidelines, including the American Urological Association (AUA) 2005 guidelines, promote a goal-oriented approach to therapy and emphasise that PDE-5 therapy should be offered to patients with ED as a first-line treatment option, unless contraindicated. Evidence-based studies have identified an association between ED and the presence of risk factors for cardiovascular and other vascular diseases, implicating ED as a marker for other vascular conditions. Therefore, the importance of screening and diagnosis in the primary care setting is paramount in the diagnosis and management of ED-associated comorbidities. This review provides an update on ED screening and management focusing on the use of PDE-5 inhibitor therapy in the primary care setting and also discusses clinical efficacy parameters with regard to recent results from clinical trials.

Chronic sildenafil in men with diabetes and erectile dysfunction

Erectile dysfunction frequently represents a neurovascular complication of diabetes mellitus, and it has been calculated that almost 50% of diabetic men will have erectile dysfunction within 6 years after diagnosis. Penile endothelial and smooth muscle cell dysfunction are due to molecular pathway abnormalities (i.e., activation of PKC, increased oxidative stress and overproduction of advanced-glycosylation end products). The response rate to oral drug therapies, such as sildenafil, is lower than in most other groups. Because therapeutic alternatives (i.e., intracavernous injections with vasoactive agents) are not curative, clinical trials aimed to demonstrate rehabilitative effects with daily phosphodiesterase type-5 inhibitors are ongoing. If this approach proves successful, it will determine many advantages over the intracavernosal treatment and potentially induce sexual rehabilitation.

Influence of a single dose of 20 mg tadalafil, a phosphodiesterase 5 inhibitor, on ambulatory blood pressure in subjects with hypertension

AIMS

To test the non-inferiority of a single dose of tadalafil 20 mg compared with placebo with respect to 26-h mean ambulatory systolic and diastolic blood pressure in treated and untreated hypertensive subjects.

METHODS

A multicentre, randomized, double-blind, placebo-controlled crossover study in 114 subjects with hypertension (36 subjects on no therapy with daytime mean ambulatory blood pressure >/= 140/85 mmHg; 38 subjects on two to four classes of antihypertensive agents with daytime mean ambulatory blood pressure >/=140/85 mmHg and 40 subjects on two to four classes of antihypertensive agents with ambulatory blood pressure < 140/85 mmHg).

RESULTS

Overall tadalafil reduced mean ambulatory blood pressure monitor systolic and diastolic blood pressure by 4.8 mmHg [95% confidence interval (Cl) 3.7, 5.9; P < 0.01] and 2.9 mmHg (95% CI 1.9, 3.6; P < 0.01), respectively, compared with placebo. In hypertensive subjects with uncontrolled blood pressure on two to four classes of antihypertensive agents (n = 36) tadalafil reduced mean ABPM systolic and diastolic blood pressure by 7.5 mmHg (95% CI 5.4, 9.6; P < 0.01) and 4.3 mmHg (95% CI 6.1, 8.9; P < 0.01) compared with placebo.

CONCLUSIONS

In patients with uncontrolled hypertension on multiple agents the addition of tadalafil 20 mg lowered mean 26-h blood pressure.

The role of nitric oxide in erectile dysfunction: implications for medical therapy

Erectile dysfunction is a common, multifactorial disorder that is associated with aging and a range of organic and psychogenic conditions, including hypertension, hypercholesterolemia, diabetes mellitus, cardiovascular disease, and depression. Penile erection is a complex process involving psychogenic and hormonal input, and a neurovascular nonadrenergic, noncholinergic mechanism. Nitric oxide (NO) is believed to be the main vasoactive nonadrenergic, noncholinergic neurotransmitter and chemical mediator of penile erection. Released by nerve and endothelial cells in the corpora cavernosa of the penis, NO activates soluble guanylyl cyclase, which increases 3',5'-cyclic guanosine monophosphate (cGMP) levels. Acting as a second messenger molecule, cGMP regulates the activity of calcium channels as well as intracellular contractile proteins that affect the relaxation of corpus cavernosum smooth muscle. Impaired NO bioactivity is a major pathogenic mechanism of erectile dysfunction. Treatment of erectile dysfunction often requires combinations of psychogenic and medical therapies, many of which have been only moderately successful in the past. The advent of oral phosphodiesterase type 5 (PDE-5) inhibitors, however, has greatly enhanced erectile dysfunction treatment; patients have demonstrated high tolerability and success rates for improved erectile function. The efficacy of the PDE-5 inhibitors also serves to illustrate the importance of the NO-cGMP pathway in erectile function since these agents counteract the degradation of NO-generated cGMP. Because not all patients respond to PDE-5 inhibitors, additional therapies are being investigated, such as soluble guanylyl cyclase activators and NO donors, which act on NO-independent and NO-dependent pathways, respectively.

An observational cohort study investigating the cardiovascular safety of tadalafil when prescribed in primary care in England: mortality due to ischaemic heart disease

OBJECTIVE

To examine the cardiovascular safety of tadalafil, a phosphodiesterase type-5 inhibitor used for treating erectile dysfunction in patients prescribed this drug by general practitioners (GPs) in England in 2003, focusing on mortality due to ischaemic heart disease (IHD).

PATIENTS AND METHODS

Patients in this observational cohort study were identified from dispensed prescriptions for tadalafil issued by GPs from February to November 2003. Demographic and outcome data were requested from patients' GPs using a postal questionnaire. A standardized mortality ratio (SMR) was calculated using indirect standardization for all deaths from IHD or myocardial infarction (MI) in male patients who were prescribed tadalafil, regardless of whether they were taking tadalafil at the time, compared to those in the English male population (2002).

RESULTS

Clinical information was obtained for 6266 patients; patient sex could not be confirmed for 37 but in the remaining 6229 the median age was 61 years (interquartile range 53-68). The age was not specified for 2361 (37.7%) of the patients. Excluding patients not taking tadalafil at the time of the event, cardiovascular events included chest pain in 20, angina in 18, MI in 15 (including six fatal) and IHD in 11 (including five fatal). There were also six deaths where the cause was not ascertained; five of these patients were known to be male. Comparison of mortality due to IHD or MI for men with those in the English male population (2002) provided an SMR of 0.91 (95% confidence interval 0.50-1.48).

CONCLUSIONS

The results from this study suggest a similar incidence of death due to IHD or MI in men prescribed tadalafil to that in the male English population. However, due to possible under-reporting and the limitations of using an external comparator, these results should be interpreted in context with other studies on the cardiovascular effects and safety of tadalafil.

Sex, the heart, and heart failure

In the modern era of pharmacologic treatment of erectile dysfunction, men with heart disease increasingly approach their physicians regarding the possibility of restoring sexual activity. At the same time, patients are also frequently aware of public figures that have reportedly died during coitus, often in the arms of their mistresses or prostitutes. Added to this is the perception of patients, and oftentimes their physicians, that coitus and orgasm are associated with a near maximal or even "supermaximal" cardiac workload and therefore may be hazardous for a diseased heart. Accordingly, knowledge of the cardiovascular effects of sexual activity, the risks of triggering a cardiovascular event, and the potential risks inherent in the use of drug therapy of male impotence is important to properly advise patients and their spouses regarding this sensitive issue.

Infarto agudo de miocardio asociado al consumo de sildenafil. Aportación de caso y revisión de la literatura

Erectile dysfunction affects more than 30 million men in The United States. Since the FDA approved the use of Sildenafil, prescription of this medication has been raising. Adverse events of Sildenafil includes: fatigue, dyspnea, and hypotension. Reported adverse cardiac events associated with the medication use include myocardial infarction, ventricular tachycardia, angina and death, raising concerns about the safety of this agent in patients with coronary artery disease. Published guidelines regarding the management of cardiac patients with erectile dysfunction suggest that Sildenafil may be hazardous in patients with ischemic heart disease. In patients using Sildenafil, myocardial infarctions have been reported to the Food and Drug Administration. Now, we report a patient with myocardial infarction after taking 100 mg of Sildenafil without sexual activity.

Cardiovascular safety of sildenafil citrate (Viagra®): An updated perspective

Sildenafil citrate (Viagra; Pfizer Inc, New York, NY) relaxes vascular smooth muscle, resulting in modest reductions in blood pressure that are insufficient to stimulate a reflex increase in heart rate. These blood pressure reductions are similar for healthy men and men with coronary artery disease (CAD) or who use antihypertensive drugs. Sildenafil does not affect the force of cardiac contraction, and cardiac performance is unaffected. Sildenafil is mildly vasodilating in the coronary circulation and does not increase the risk of ventricular arrhythmia. During exercise and recovery, sildenafil does not cause clinically significant alterations in hemodynamic parameters in men with CAD, and it has no negative effects on coronary oxygen consumption, ischemia, or exercise capacity. Clinical trial data from >13,000 patients, 7 years of international postmarketing data, and observational studies of >28,000 men in the United Kingdom and 3813 men in the European Union reveal that (1) there are no special cardiovascular concerns when sildenafil is used in accordance with product labeling and (2) the risk for serious events such as myocardial infarction or death is not increased. However, because safety has not been established in patients with recent serious cardiovascular events, hypotension or uncontrolled hypertension, or retinitis pigmentosa, physicians should consult their current local prescribing information before prescribing sildenafil for these patients. Among men with erectile dysfunction treated with sildenafil, the adverse event profile is similar overall to that in men with comorbid cardiovascular disease (CVD), it is similar between those with and without CAD, and it is similar between those who take and those who do not take antihypertensive drugs (regardless of the number or class). In a controlled interaction study of sildenafil and amlodipine, the mean additional reduction in supine blood pressure was 8 mm Hg systolic and 7 mm Hg diastolic. Sildenafil should be used with caution in patients who take alpha-blockers because coadministration may lead to symptomatic hypotension in some individuals. When sildenafil is coadministered with an alpha-blocker, patients should be stable on alpha-blocker therapy before initiating sildenafil treatment and sildenafil should be initiated at the lowest dose. Also, in the absence of information specific to mixed alpha/beta blockers, such as carvedilol and labetalol, similar care should be taken as for alpha-blockers. Sildenafil potentiates the hypotensive effects of nitrates, and its administration to patients who are using organic nitrates in any form, either regularly or intermittently, is contraindicated. Before prescribing sildenafil, physicians should carefully consider whether their patients with underlying CVD could be affected adversely by resuming sexual activity. Management recommendations based on cardiovascular risk, from the Second Princeton Consensus Conference, are presented.

[Erectile dysfunction, a new symptom for the cardiologist]

During many years, the symptom of erectile dysfunction was a matter for the urologist or the sexologist without efficacious treatment. Since 1999, the unexpected efficacy of sildenafil initially tested as a coronary vasodilatator emphasized the major role of an endothelial dysfunction potentially corrected by type 5 phosphodiesterase inhibitors (5-PDEI), which are able to reinforce the NO-dependant vasodilatation of cavernous arteries. Due to the medicalisation and the mediatisation of erectile dysfunction during the past five years, this symptom is now a matter for the cardiologist. The first reason was the query of cardiovascular safety of 5-PDEI. American and Britannic registries have established a good cardiovascular tolerability of these drugs including in patients with coronary heart disease according to the respect of contraindication in cases of coprescription with nitrates. The second was the association of erectile dysfunction with many cardiovascular risk factors concerned by the cardiologist. The third reason was the observation that erectile dysfunction could be a potential marker to identify patients with silent myocardial ischemia and relevant coronary artery disease. The Princeton consensus provides guidelines to help the cardiologist in the evaluation of patients with erectile dysfunction according to the cardiovascular risk level. Henceforth, erectile dysfunction should be considered by the cardiologist as "a sound of silence" of myocardial ischemia and should encourage to more aggressive evaluation and treatment of cardiovascular risk factors.

Sildenafil citrate use and the incidence of nonarteritic anterior ischemic optic neuropathy

Nonarteritic anterior ischemic optic neuropathy (NAION) has been reported rarely in men after taking sildenafil or other phosphodiesterase 5 inhibitors for erectile dysfunction (ED). The incidence of NAION in men receiving sildenafil treatment for ED was estimated using pooled safety data from global clinical trials and European observational studies. Based on clinical trial data in more than 13,000 men and on more than 35,000 patient-years of observation in epidemiologic studies, we estimated an incidence of 2.8 cases of NAION per 100,000 patient-years of sildenafil exposure. This is similar to estimates reported in general US population samples (2.52 and 11.8 cases per 100,000 men aged >or=50 years). The data cited herein do not suggest an increased incidence of NAION in men who took sildenafil for ED.

Effects of Sildenafil Citrate on Defibrillation Efficacy

INTRODUCTION

Although fatal arrhythmia and sudden death have been reported in patients taking sildenafil citrate, its effect on defibrillation efficacy has not been investigated. The aim of this study was to test the hypothesis that sildenafil citrate increases the shock strength required to successfully defibrillate during ventricular fibrillation (VF).

METHODS AND RESULTS

A total of 26 pigs (20-25 kg) were randomly assigned into three groups. In each group, the defibrillation threshold (DFT) was determined at the beginning of the study using a three-reversal up/down protocol. Each shock (RV-SVC, biphasic) was delivered after 10 seconds of VF. Group 1 (n = 10) received 50 mg and group 2 (n = 10) received 100 mg of sildenafil citrate intravenously at a rate of 2 mL/minute for 50 minutes. Group 3 (n = 6) received 100 mL of saline intravenously at the same rate as in group 1. The DFT was determined again after the drug (drug-DFT) and saline (saline-DFT) administration. For 100-mg sildenafil citrate infusion, the DFT (483 +/- 39 V, 18 +/- 3 J) was significantly (P < 0.003 and P < 0.01, respectively) higher than the control-DFT (407 +/- 123 V, 13 +/- 7 J). This sildenafil citrate infusion increased the DFT approximately 19% by voltage, and approximately 38% by total energy. After 50-mg sildenafil citrate infusion, the DFT (454 +/- 28 V, 15 +/- 2 J) was not different than the control DFT (449 +/- 28 V, 15 +/- 2 J). Saline infusion (391 +/- 18 V, 12 +/- 1 J) did not alter the control DFT (399 +/- 22 V, 12 +/- 1 J).

CONCLUSION

The 100-mg sildenafil citrate infusion, representing a supra-therapeutic plasma level, significantly increased the DFT. This finding indicates that VF occurring during supra-therapeutic sildenafil citrate treatment would require a stronger shock to successfully defibrillate.

Ocular Safety in Patients Using Sildenafil Citrate Therapy for Erectile Dysfunction

Sildenafil citrate improves erectile function in men with erectile dysfunction (ED) by selectively inhibiting cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), which is present in all vascular tissue. Sildenafil also has a weaker inhibitory action on PDE6, located in the rod and cone photoreceptors. Modest, transient visual symptoms, typically blue tinge to vision, increased brightness of lights, and blurry vision, have been reported with sildenafil use and occur more frequently at higher doses. Visual function studies in healthy subjects and in patients with eye disease suggest that sildenafil does not affect visual acuity, visual fields, and contrast sensitivity. Transient, mild impairment of color discrimination can occur around the time of peak plasma levels. Spontaneous postmarketing reports of visual adverse events, including nonarteritic anterior ischemic optic neuropathy (NAION), have been reported during the 7 years that sildenafil has been prescribed to more than 27 million men worldwide. However, because men with ED frequently have vascular risk factors that may also put them at increased risk for NAION, a causal relationship is difficult to establish. No consistent pattern has emerged to suggest any long-term effect of sildenafil on the retina or other structures of the eye or on the ocular circulation.

Sexual dysfunction and cardiac risk (the Second Princeton Consensus Conference)

Recent studies have highlighted the relation between erectile dysfunction (ED) and cardiovascular disease. In particular, the role of endothelial dysfunction and nitric oxide in ED and atherosclerotic disease has been elucidated. Given the large number of men receiving medical treatment for ED, concerns regarding the risk for sexual activity triggering acute cardiovascular events and potential risks of adverse or unanticipated drug interactions need to be addressed. A risk stratification algorithm was developed by the First Princeton Consensus Panel to evaluate the degree of cardiovascular risk associated with sexual activity for men with varying degrees of cardiovascular disease. Patients were assigned to 3 categories: low, intermediate (including those requiring further evaluation), and high risk. This consensus study from the Second Princeton Consensus Conference corroborates and clarifies the algorithm and emphasizes the importance of risk factor evaluation and management for all patients with ED. The panel reviewed recent safety and drug interaction data for 3 phosphodiesterase (PDE)-5 inhibitors (sildenafil, tadalafil, vardenafil), with emphasis on the safety of these agents in men with ED and concomitant cardiovascular disease. Increasing evidence supports the role of lifestyle intervention in ED, specifically weight loss and increased physical activity, particularly in patients with ED and concomitant cardiovascular disease. Special management recommendations for patients taking PDE-5 inhibitors who present at the emergency department and other emergency medical situations are described. Finally, further research on the role of PDE-5 inhibition in treating patients with other medical or cardiovascular disorders is recommended.

A case of erectile dysfunction and risk factors for coronary artery disease

The hypothetical case of a man with erectile dysfunction and multiple cardiovascular risk factors is presented to illustrate the use of the second Princeton Consensus Conference Guidelines. Methods to optimize efficacy of the phosphodiesterase inhibitors are described. The overall cardiovascular safety of the phosphodiesterase inhibitors and their interaction with organic nitrates and alpha blockers are discussed.

Erectile dysfunction: the need to be evaluated, the right to be treated

Erectile dysfunction (ED) is commonly associated with cardiovascular disease, which has potentially fatal consequences if not managed appropriately. Physicians and patients for a number of reasons commonly ignore ED. Increased awareness of the health consequences of ED would encourage men and health care professionals to address this condition more freely, permitting appropriate screening and treatment of cardiovascular disease. Concerns about the risks of treating ED in the cardiac patient should not prevent ED from being discussed and we suggest that early acknowledgment of ED might prevent cardiovascular morbidity and even mortality. Specific guidelines for the management of ED in cardiac patients, produced by 2 expert panels, can also be applied to men without known cardiovascular disease.

Effect of sildenafil citrate on the cardiovascular system

Sildenafil citrate is a drug commonly used to manage erectile dysfunction. It is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H -pyrazolo[4,3-d]pyrimidin-5-yl)-4 ethoxyphenyl] sulfonyl]-4-methylpiperazine citrate (C22H30N6(O4)S). It is a highly selective inhibitor of cyclic guanine monophosphate-specific phosphodiesterase type 5. In late March through mid-November 1998, the US Food and Drug Administration (FDA) published a report on 130 confirmed deaths among men (mean age, 64 years) who received prescriptions for sildenafil citrate, a period during which >6 million outpatient prescriptions (representing about 50 million tablets) were dispensed. The US FDA recently reported that significant cardiovascular events, including sudden cardiac death, have occurred in men with erectile dysfunction who were taking sildenafil citrate. These reports have raised concerns that sildenafil citrate may increase the risk of cardiovascular events, particularly fatal arrhythmias, in patients with cardiovascular disease. In the past few years, the cardiac electrophysiological effects of sildenafil citrate have been investigated extensively in both animal and clinical studies. According to extensive data available to date, sildenafil citrate has been shown to pose minimal cardiovascular risks to healthy people taking this drug. Some precautions are needed for patients with cardiovascular diseases. However, the only absolute contraindication for sildenafil citrate is the concurrent use of nitrates. This article is intended to review sildenafil citrate's cardiovascular effects, as well as current debates about its arrhythmogenic effects.

Sexual dysfunction and cardiac risk (the Second Princeton Consensus Conference)

Recent studies have highlighted the relation between erectile dysfunction (ED) and cardiovascular disease. In particular, the role of endothelial dysfunction and nitric oxide in ED and atherosclerotic disease has been elucidated. Given the large number of men receiving medical treatment for ED, concerns regarding the risk for sexual activity triggering acute cardiovascular events and potential risks of adverse or unanticipated drug interactions need to be addressed. A risk stratification algorithm was developed by the First Princeton Consensus Panel to evaluate the degree of cardiovascular risk associated with sexual activity for men with varying degrees of cardiovascular disease. Patients were assigned to 3 categories: low, intermediate (including those requiring further evaluation), and high risk. This consensus study from the Second Princeton Consensus Conference corroborates and clarifies the algorithm and emphasizes the importance of risk factor evaluation and management for all patients with ED. The panel reviewed recent safety and drug interaction data for 3 phosphodiesterase (PDE)-5 inhibitors (sildenafil, tadalafil, vardenafil), with emphasis on the safety of these agents in men with ED and concomitant cardiovascular disease. Increasing evidence supports the role of lifestyle intervention in ED, specifically weight loss and increased physical activity, particularly in patients with ED and concomitant cardiovascular disease. Special management recommendations for patients taking PDE-5 inhibitors who present at the emergency department and other emergency medical situations are described. Finally, further research on the role of PDE-5 inhibition in treating patients with other medical or cardiovascular disorders is recommended.

Pharmacotherapy of erectile dysfunction: focus on cardiovascular safety

Therapy of erectile dysfunction has been revolutionised in recent years, as specific pharmacological inhibitors of phosphodiesterase 5 (PDE5), such as sildenafil, tadalafil, or vardenafil, were shown to be highly effective in the treatment of erectile dysfunction. They dilate arterial smooth muscle cells of the corpora cavernosa, which express PDE5 abundantly, by inhibiting the breakdown of 3'5'-cyclic guanosine monophosphate. Despite theoretical concerns of a reduced myocardial tolerance to ischaemia or promoting cardiac arrhythmias, randomised trials and retrospective analyses do not support an increased cardiac risk with oral treatment. Therapeutic doses of PDE 5 inhibitors exhibit slight blood pressure lowering effects, and do not appear to compromise coronary blood flow in coronary artery disease. However, the combination of PDE5 inhibitors with any nitric oxide donor is absolutely contraindicated because of potentially life-threatening hypotension. Before prescribing medication for erectile dysfunction, any patient with cardiovascular disease should be evaluated for a potential risk of a cardiovascular event during sexual activity according to the Princeton Consensus Panel. When a stable cardiac condition can be achieved (low risk group), oral treatment for erectile dysfunction may be appropriate.

Pharmacological preconditioning with sildenafil: Basic mechanisms and clinical implications

The phosphodiesterase type-5 (PDE5) inhibitor, sildenafil, is the first drug developed for treatment of erectile dysfunction in patients. Experimental data in animals show that sildenafil has a preconditioning-like cardioprotective effect against ischemia/reperfusion injury in the intact heart. Mechanistic studies suggest that sildenafil exerts cardioprotection through NO generated from eNOS/iNOS, activation of protein kinase C/ERK signaling and opening of mitochondrial ATP-sensitive potassium channels. Additional studies show that the drug attenuates cell death resulting from necrosis and apoptosis, and increases the Bcl2/Bax ratio through NO signaling in adult cardiomyocytes. Emerging new data also suggest that sildenafil may be used clinically for treatment of pulmonary arterial hypertension and endothelial dysfunction. Future demonstration of the cardioprotective effect in patients with the relatively safe and effective FDA-approved PDE5 inhibitors such as sildenafil could have an enormous impact on bringing the long-studied phenomenon of ischemic and pharmacologic preconditioning to the clinical forefront.

Erectile dysfunction in patients with coronary artery disease

Recent studies suggest that erectile dysfunction (ED) may be an early marker of endothelial dysfunction and coronary artery disease (CAD). Conversely, patients with CAD commonly have ED. The phosphodiesterase 5 (PDE5) inhibitors are very effective for the treatment of ED in patients with CAD. Numerous studies show that this class of drugs is in general safe in patients with stable CAD and these agents do not exacerbate ischemia in men with CAD undergoing exercise stress testing. Analysis of placebo-controlled trials did not show an increase in cardiovascular events among men receiving PDE5 inhibitors, and post-marketing surveillance studies with sildenafil did not observe an increase in cardiovascular events compared to expected age-matched rates. Organic nitrates remain a contraindication for PDE5 inhibitors and alpha blockers have precautions/contraindications depending upon specific drugs. The Princeton Consensus Guidelines (soon to be updated) suggest a logical approach to the patient with CAD seeking therapy for sexual dysfunction.

Phosphodiesterase-5 inhibitor sildenafil preconditions adult cardiac myocytes against necrosis and apoptosis. Essential role of nitric oxide signaling

We investigated the effect of sildenafil in protection against necrosis or apoptosis in cardiomyocytes. Adult mouse ventricular myocytes were treated with sildenafil (1 or 10 microM) for 1 h before 40 min of simulated ischemia (SI). Necrosis was determined by trypan blue exclusion and lactate dehydrogenase release following SI alone or plus 1 or 18 h of reoxygenation (RO). Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated nick end labeling assay and mitochondrial membrane potential measured using a fluorescent probe 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1). Sildenafil reduced necrosis as indicated by decrease in trypan blue-positive myocytes and leakage of lactate dehydrogenase compared with untreated cells after either SI or SI-RO. The number of terminal deoxynucleotidyl transferase-mediated nick end labeling-positive myocytes or loss of JC-1 fluorescence following SI and 18 h of RO was attenuated in the sildenafil-treated group with concomitant inhibition of caspase 3 activity. An early increase in Bcl-2 to Bax ratio with sildenafil treatment was also observed in myocytes after SI-RO. The increase of Bcl-2 expression by sildenafil was inhibited by nitric-oxide synthase (NOS) inhibitor, L-nitro-amino-methyl-ester. The drug also enhanced mRNA and protein content of inducible NOS (iNOS) and endothelial NOS (eNOS) in the myocytes. Sildenafil-induced protection against necrosis and apoptosis was absent in the myocytes derived from iNOS knock-out mice and was attenuated in eNOS knock-out myocytes. The up-regulation of Bcl-2 expression by sildenafil was also absent in iNOS-deficient myocytes. Reverse transcription-PCR, Western blots, and immunohistochemical assay confirmed the expression of phosphodiesterase-5 in mouse cardiomyocytes. These data provide strong evidence for a direct protective effect of sildenafil against necrosis and apoptosis through NO signaling pathway. The results may have possible therapeutic potential in preventing myocyte cell death following ischemia/reperfusion.

Safety and Tolerability of Oral Erectile Dysfunction Treatments in the Elderly

Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men worldwide. It is generally accepted that sexual function tends to decline with aging, which is often associated with a higher prevalence of sexual problems, including ED and loss of libido. As the mean age of men seeking medical help for sexual dysfunction continues to increase, it is important to assess the safety and tolerability of currently available medical treatments in elderly men, who often share other co-morbidities that should be carefully evaluated when any type of ED therapy is considered. With this aim in mind, a MEDLINE search was conducted from 1 January 1998 to 31 May 2004 to identify studies assessing the efficacy, safety and tolerability of treatments for ED in the elderly. Particular care was taken to assess the cardiovascular safety of oral drugs for ED in this subset of patients, who often have multiple cardiovascular risk factors which contribute to a complicated clinical scenario. The most important conclusion of the paper is that the high efficacy, reliability, safety and tolerability of oral ED treatments makes them appropriate first-line therapies for elderly patients with ED.

The Art and Science of Risk Management

The research-based pharmaceutical industry in the US strongly supports the concepts of risk management and sees formal risk management as playing a major role in the development of safe medicines for the public, as well as providing a mechanism to ensure that decisions concerning individual drug benefit and risk are made based on scientific evidence. Safe medicines refer to those drugs whose benefits have been found to outweigh their risks when they are used according to the approved labelling. Risk management is the comprehensive and proactive application of scientifically based methodologies to identify, assess, communicate and minimise risk throughout the life cycle of a drug so as to establish and maintain a favourable benefit-risk balance in patients. Although there are certainly a number of global risk management initiatives in place or being undertaken, harmonisation has yet to be achieved. Industry is faced with a variety of different risk management approaches and tools. There is a need to move the focus of risk management from the post-approval arena to earlier in the development process and tools need to be developed to support risk management throughout the lifecycle of a drug. The focus in the US on risk minimalisation strategies will also be an area for methodological development. A key factor in the success of overall risk management is the dialogue between industry and regulators throughout the development, review and marketing of the product. It is through such dialogue that appropriate, efficient and effective risk management strategies will be developed and implemented and the best decisions regarding the safe use of pharmaceutical products will be made.

Erectile dysfunction in heart disease patients

Atherosclerosis is a general health problem that not only affects the coronary arteries but also (in men) the penile arteries, thus contributing to organic causes of erectile dysfunction (ED) in heart disease patients. These organic causes are intertwined with psychological and pharmacological causes because medication prescribed for heart disease patients may also cause ED. The incidence of ED after myocardial infarction ranges from 38 to 78%. As sexual intercourse involves physical exertion, the medical history, ventricular function determined through echocardiography, and stress testing are used to classify patients into various groups where coital activity represents a greater or lesser cardiovascular risk. The energy requirements for intercourse are not high, ranging from 3.7 metabolic equivalents (METs) of energy expenditure at resting state during the preorgasmic phase to 5 METs during orgasm. The Bruce protocol for exercise stress testing is a six-stage protocol with changes in the slope and speed of the treadmill. As a general rule, a patient who completes the first two stages of the Bruce protocol has a functional capacity greater than 7 METs, which is considered sufficient for sexual intercourse. The physician or cardiologist concerned should institute first-line treatment with oral drugs according to the indications listed below. If sexual activity is not contraindicated, the treatment of choice for ED in heart disease patients is oral therapy with sildenafil, except in those cases in which its use is contraindicated. Specific recommendations are discussed.

Update on Clinical Trials of Tadalafil Demonstrates No Increased Risk of Cardiovascular Adverse Events

INTRODUCTION

Cardiovascular disease and erectile dysfunction (ED) share similar risk factors and often occur concomitantly. Therefore, men with ED may be at increased risk for cardiovascular adverse events.

AIM

The aim of this retrospective analysis was to evaluate the cardiovascular adverse events in clinical trials of tadalafil, an effective medication for the treatment of ED.

METHODS

An integrated analysis of cardiovascular adverse events was performed on a database from 35 controlled clinical trials (placebo [N = 2,118] and tadalafil [N = 5,228]) and eight open-label trials of tadalafil (tadalafil [N = 6,939]). Some patients in controlled trials also received tadalafil in the open-label extension phase of four trials. Across all trials, the dose range of tadalafil was 2-25 mg, with the majority of patients receiving tadalafil 20 mg. This analysis represents an update of previous published results.

RESULTS

In 35 controlled tadalafil clinical trials, the incidence of cardiovascular adverse events was low and comparable in tadalafil- and placebo-treated patients. The rate of myocardial infarction (MI) across all controlled and open-label studies was 0.33 per 100 patient-years in tadalafil-treated patients (N = 10,460, patient exposure = 5,088 patient-years). The MI rate in tadalafil-treated patients was comparable to that in placebo-treated patients (0.41 per 100 patient-years; N = 2,118; 489 patient-years), and to that in an age-standardized male population (0.6 per 100 patient-years). The cardiac mortality rate in tadalafil-treated patients across all studies (N = 10,460) was 0.12 per 100 patient-years which was not increased compared with the cardiac mortality rate of 0.26 per 100 patient-years reported in an age-standardized male population.

CONCLUSIONS

In tadalafil clinical trials, the incidence of cardiovascular adverse events in patients receiving tadalafil was low and comparable to placebo. Tadalafil did not increase the rate of MI or cardiac mortality compared with reported rates from epidemiological studies. This favorable cardiovascular safety profile for tadalafil is important, because men with ED commonly have cardiovascular disease and may seek medical therapy for ED.

Event analysis techniques

Event analysis (EA), a qualitative research technique adapted from the fields of anthropology and sociology, can be used to describe and explain social interactions and behaviors associated with complicated clinical situations. Event analysis is useful in limiting the focus of data collection in complex settings and in obtaining and managing multiple perspectives about an event of interest while situating the event within appropriate social and environmental contexts. This article reviews contemporary uses of EA in clinical nursing research, describes the modification and application of EA techniques to common methods of data gathering (observation, interview, and document review) in clinical settings, and presents recommendations for conducting EA in clinical settings by using exemplars from a current study.

Evaluation of the safety of sildenafil for male erectile dysfunction: experience gained in general practice use in England in 1999

OBJECTIVE

To examine the safety of sildenafil, the first of the phosphodiesterase type 5 inhibitors licensed for the treatment of male erectile dysfunction (ED), as used in general medical practice in England, quantifying the incidence of a range of events in patients treated with sildenafil, and identifying any previously unrecognized adverse drug reactions.

METHODS

In a postmarketing observational cohort study using prescription-event monitoring (PEM), exposure data were derived from dispensed prescription details for patients who started treatment between April and August 1999. Outcome data were derived from "green form" questionnaires (GFs) returned by general practitioners (GPs). RESULTS In all, 24 835 (54.7%) of GFs posted to GPs were returned, of which 22 473 contained useful data for 22 471 male and two female patients. The major primary indications/clinical context of prescribing were impotence (16 583, 73.8%) and diabetes mellitus (183, 0.8%); 145 events were reported as adverse drug reactions to sildenafil. GPs recorded 3951 reasons for stopping sildenafil, and ischaemic heart disease (IHD) in 135 patients was the commonest clinical reason reported. The clinical condition reported most frequently in the first month of observation was diabetes mellitus and/or hyperglycaemia (in 99 events). A standardized mortality ratio (SMR) for deaths caused by IHD in the first 8893 of 22 473 patients was 31.41 (95% confidence interval 18.29-50.29), using the comparator population of males in England in 1998.

CONCLUSION

This study identified the safety profile of sildenafil as used in the community, showing no unexpected events. The SMR analysis of deaths from IHD provided no evidence to suggest a higher incidence of deaths in the study cohort than in the male population in England.

Erectile dysfunction in the cardiac patient

Erectile dysfunction (ED) is a common problem in men over 40-50 years of age. Risk factors include: diabetes, lipid abnormalities, smoking, hypertension, obesity, and lack of physical activity. Oral phosphodiesterase-5 inhibitors appear effective and safe in most cardiac patients.

Sildenafil in patients with cardiovascular disease

Cardiologists are seeing increasing numbers of patients with erectile dysfunction (ED), which frequently coexists with cardiovascular disease. The pharmacologic profile of the new class of phosphodiesterase (PDE) inhibitors-specifically PDE5 inhibitors-and their potential effects on hemodynamic variables have therefore become significant factors in therapeutic decision making. Most of the published data linking PDE5 inhibitor effects and cardiovascular disease relate to sildenafil, although >or=2 new agents are in various stages of development and clinical trials. Sildenafil and other PDE5 inhibitors act on vascular smooth muscle, predominantly in the corpus cavernosum. PDE5 is not found in cardiomyocytes, and no effect of PDE5 inhibition on cardiac contractility has been demonstrated. On the basis of a safety database comprising thousands of men with ED, sildenafil has demonstrated minimal adverse effects in men with stable ischemia, hypertension, and/or severe coronary artery disease. Sildenafil has modest effects on hemodynamic variables and has been shown to increase coronary artery flow reserve. Alone or combined with >or=1 antihypertensive medication, sildenafil did not increase the incidence of adverse events or hypotensive episodes. Sildenafil-associated decreases in systolic and diastolic blood pressure, the result of its vasodilator activity, have been modest. Sildenafil has decreased both elevated pulmonary vascular resistance and elevated pulmonary artery pressures in patients with pulmonary vascular disease. Beneficial changes in hemodynamics have been observed with the use of sildenafil in patients with congestive heart failure with underlying ischemic and other dilated cardiomyopathies. No association between sildenafil and increased cardiovascular morbidity or mortality has emerged in analyses of clinical trial data.

Cardiovascular effects of tadalafil

To determine the effects of tadalafil on the cardiovascular system, safety assessments were performed on a database of >4000 subjects who received tadalafil in >60 clinical pharmacology, phase 2, phase 3, and open-label studies. In healthy subjects, tadalafil resulted in small changes in blood pressure, which are not believed to be clinically relevant. Daily administration of tadalafil 20 mg for 26 weeks in healthy male subjects or patients with mild erectile dysfunction resulted in blood pressure changes similar to those observed after placebo administration. In patients with coronary artery disease (CAD), tadalafil administration before nitrate administration resulted in small decreases in blood pressure. The resulting mean maximal change in standing systolic blood pressure (SBP) after coadministration of sublingual nitroglycerin in patients with chronic stable angina was -36 mm Hg for tadalafil 5 mg, -31 mm Hg for tadalafil 10 mg, and -28 mm Hg for placebo. In addition, a larger number of men had a standing SBP <85 mm Hg after coadministration of sublingual nitroglycerin and tadalafil 5 mg (p <0.001 vs placebo) or tadalafil 10 mg (p <0.01 vs placebo) compared with coadministration with placebo. In patients with chronic stable angina taking doses of isosorbide mononitrate on a long-term basis, the mean maximal change in standing SBP was -23 mm Hg for placebo, -23 mm Hg for tadalafil 5 mg, and -26 mm Hg for tadalafil 10 mg. In a study of older subjects (>or=55 years of age) with no overt evidence of CAD, the resulting mean maximal change in standing SBP after coadministration of sublingual nitroglycerin was -25 mm Hg for tadalafil 10 mg, -29 mm Hg for sildenafil 50 mg, and -25 mm Hg for placebo. Cardiac mortality rates in tadalafil studies are consistent with the expected rate in this male population. Across all studies, the incidence rate of myocardial infarction was low in tadalafil-treated patients (0.43 per 100 patient-years) compared with patients who received placebo (0.6 per 100 patient-years), and the incidence rate was comparable to that observed in the age-standardized male population (0.60 per 100 patient-years). The incidence rate of presumed thrombotic strokes in tadalafil studies (0.27 per 100 patient-years) is comparable to the expected rate in this patient population. The data presented herein suggest that tadalafil can be safely used by healthy subjects and by patients with cardiovascular diseases. As with sildenafil, the use of tadalafil is contraindicated in patients receiving nitrate therapy because of the potential for significant hypotensive effects.