The effect of tadalafil on the time to exercise-induced myocardial ischaemia in subjects with coronary artery disease

Cardiac Effects of Phosphodiesterase-5 Inhibitors: Efficacy and Safety

The coexistence of cardiovascular disease and erectile dysfunction is widespread, possibly owing to underlying endothelial dysfunction in both diseases. Millions of patients with cardiovascular disease are prescribed phosphodiesterase-5 (PDE5) inhibitors for the management of erectile dysfunction. Although the role of PDE5 inhibitors in erectile dysfunction therapy is well established, their effects on the cardiovascular system are unclear. Preclinical studies investigating the effect of PDE5 inhibitors on ischemia-reperfusion injury, pressure overload-induced hypertrophy, and chemotoxicity suggested a possible clinical role for each of these medications; however, attempts to translate these findings to the bedside have resulted in mixed outcomes. In this review, we explore the biologic preclinical effects of PDE5 inhibitors in mediating cardioprotection. We then examine clinical trials investigating PDE5 inhibition in patients with heart failure, coronary artery disease, and ventricular arrhythmias and discuss why the studies likely have yet to show positive results and efficacy with PDE5 inhibition despite no safety concerns.

Protective or Inhibitory Effect of Pharmacological Therapy on Cardiac Ischemic Preconditioning: A Literature Review

Ischemic preconditioning (IP) is an innate phenomenon, triggered by brief, non-lethal cycles of ischemia/reperfusion applied to a tissue or organ that confers tolerance to a subsequent more prolonged ischemic event. Once started, it can reduce the severity of myocardial ischemia associated with some clinical situations, such as percutaneous coronary intervention (PCI) and intermittent aortic clamping during coronary artery bypass graft surgery (CABG). Although the mechanisms underlying IP have not been completely elucidated, several studies have shown that this phenomenon involves the participation of cell triggers, intracellular signaling pathways, and end-effectors. Understanding this mechanism enables the development of preconditioning mimetic agents. It is known that a range of medications that activate the signaling cascades at different cellular levels can interfere with both the stimulation and the blockade of IP. Investigations of signaling pathways underlying ischemic conditioning have identified a number of therapeutic targets for pharmacological manipulation. This review aims to present and discuss the effects of several medications on myocardial IP.

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.

A Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Effect of Erenumab on Exercise Time During a Treadmill Test in Patients With Stable Angina

Objective

To determine the potential impact of erenumab, a human anti‐calcitonin gene‐related peptide (CGRP) receptor monoclonal antibody, on total exercise time (TET), time to exercise‐induced angina, and ST depression in a double‐blind, placebo‐controlled study in patients with stable angina due to documented coronary artery disease.

Background

The relative importance of the CGRP receptor pathway during myocardial ischemia has not been established.

Methods

An exercise treadmill test was conducted following a single IV infusion of erenumab 140 mg or placebo. The primary endpoint was the change from baseline in exercise duration as measured by TET with a noninferiority margin of −90 seconds. Safety follow‐up visits occurred through week 12. Eighty‐eight participants were included in the analysis.

Results

LS mean (SE) change in TET was −2.9 [14.8] seconds in the erenumab group and 8.1 [14.4] seconds in placebo; adjusted mean (90% CI) treatment difference was −11.0 (–44.9, 22.9) seconds. The CI lower bound (–44.9 sec) did not reach pre‐defined non‐inferiority margin of −90 seconds, demonstrating that TET change from baseline in the erenumab group was non‐inferior to placebo. There was no difference in time to exercise‐induced angina in erenumab and placebo groups (median [90% CI] time of 500 [420, 540] vs 508 [405, 572] seconds; hazard ratio [90% CI]: 1.11 [0.73, 1.69], P = .69) or time to onset of ≥1 mm ST‐segment depression (median [90% CI] time of 407 [380, 443] vs 420 [409,480] seconds; hazard ratio [95% CI]: 1.14 [0.76, 1.69], P = .59). Adverse events were reported by 27% and 32% of patients in erenumab and placebo groups.

Conclusions

Erenumab did not adversely affect exercise time in a high cardiovascular risk population of patients, supporting that inhibition of the canonical CGRP receptor does not worsen myocardial ischemia.

A randomized, placebo-controlled study of the effects of telcagepant on exercise time in patients with stable angina

Telcagepant is a calcitonin gene-related peptide (CGRP) receptor antagonist being evaluated for acute migraine treatment. CGRP is a potent vasodilator that is elevated after myocardial infarction, and it delays ischemia during treadmill exercise. We tested the hypothesis that CGRP receptor antagonism does not reduce treadmill exercise time (TET). The effects of supratherapeutic doses of telcagepant on TET were assessed in a double-blind, randomized, placebo-controlled, two-period, crossover study in patients with stable angina and reproducible exercise-induced angina. Patients received telcagepant (600 mg, n = 46; and 900 mg, n = 14) or placebo and performed treadmill exercise at T(max) (2.5 h after the dose). The hypothesis that telcagepant does not reduce TET was supported if the lower bound of the two-sided 90% confidence interval (CI) for the mean treatment difference (telcagepant-placebo) in TET was more than -60 s. There were no significant between-treatment differences in TET (mean treatment difference: -6.90 (90% CI: -17.66, 3.86) seconds), maximum exercise heart rate, or time to 1-mm ST-segment depression using pooled data or with stratification for dose.

Managing Erectile Dysfunction in Patients With Cardiovascular Diseases: The Efficacy and Safety of Phosphodiesterase-5 Inhibitors

Patients with cardiovascular disease have a high prevalence of erectile dysfunction. Recent evidence demonstrated that erectile dysfunction is an early indication of coronary artery disease. Phosphodiesterase-5 (PDE-5) inhibitors are effective in managing erectile dysfunction due to cardiovascular disease. However, when used together with nitrates or other vasodilators such as alpha-antagonists, they may cause hypotension. Clinical studies demonstrated that in patients with stable coronary artery disease, heart failure, and hypertension controlled by medications who were not receiving nitrates, PDE-5 inhibitors were well tolerated. Therefore, it is important for clinicians to carefully evaluate each patient before initiating PDE-5 inhibitors. PDE-5 inhibitors are absolutely contraindicated with concurrent nitrate use. No PDE-5 inhibitors should be administered within 12 hours after the last nitrate dose. If a patient develops chest pain while taking PDE-5 inhibitors, nitrates should be administered only after the PDE-5 inhibitors have been washed out of the system, based on the half-life of individual agents (washed-out period for sildenafil ∽20 hours; vardenafil ∽ 24 hours; tadalafil ∽88 hours [or 3-4 days]). If symptomatic hypotension occurs, patients should be put in a Trendelenburg position. Fluid resuscitation therapy and alpha-agonists should be used to support blood pressure, if necessary. PDE-5 inhibitors have not been studied in patients with severe and unstable cardiac conditions.

Medication and dosage considerations in the prophylaxis and treatment of high-altitude illness

With increasing numbers of people traveling to high altitude for work or pleasure, there is a reasonable chance that many of these travelers have preexisting medical conditions or are receiving various medications at the time of their sojourn. As with all travelers to high altitude, they are at risk for altitude illnesses such as acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema. While there are clear recommendations for pharmacologic measures to prevent or treat these illnesses, these recommendations are oriented toward healthy individuals and do not take into account the presence of preexisting medical conditions. In this review, we consider how the choice and dose of the medications used in the management of altitude illness-acetazolamide, dexamethasone, nifedipine, tadalafil, sildenafil, and salmeterol-are affected by a patient's underlying medical conditions. We discuss the indications and current dosing recommendations for individuals without underlying disease, and then consider how drug selection or dosing regimens will be affected by the presence of renal insufficiency, hepatic insufficiency, other important medical conditions, and the potential for serious drug interactions. We include comments about interactions with antimalarial medications and antibiotics used in the treatment of traveler's diarrhea, as well as the safety of use during pregnancy. By giving these issues adequate consideration, clinicians can increase the chances that properly evaluated patients with underlying medical conditions will enjoy a safe trip to high altitude.

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.

Do vardenafil and tadalafil have advantages over sildenafil in the treatment of erectile dysfunction?

Erectile dysfunction (ED) affects up to 50% of men between the ages of 40 and 70 years of age. Sildenafil, vardenafil and tadalafil have all been shown to be similarly effective in the treatment of men with ED of vary etiologies, to have similar adverse effects profiles, and to improve quality-of-life by similar amounts. As these phosphodiesterase 5 (PDE5) inhibitors all increase the hypotensive effects of nitrates, they are not suitable for use in patients taking nitrates for the treatment of ischaemic heart disease. All three inhibitors must be used with caution in patients taking alpha(1)-adrenoceptors antagonists for benign prostatic hyperplasia. Although nonarteritic anterior ischaemic neuropathy has been reported in some users of the PDE5 inhibitors, there is no conclusive evidence that PDE5 inhibitors cause this rare effect. Tadalafil has a longer half-life than sildenafil or vardenafil, and a longer duration of action than sildenafil and vardenafil. Most preference studies have shown tadalafil to be preferred, but there are serious limitations to some of these studies. One approach to treatment is to give each patient a short- and long-acting agent, and for individuals to decide their preference.

Effects of tadalafil on myocardial blood flow in patients with coronary artery disease

OBJECTIVE

Erectile dysfunction and coronary artery disease share similar risk factors. Although phosphodiesterase-5 inhibitors used to treat erectile dysfunction do not adversely affect hemodynamic parameters in patients with coronary artery disease, their effects on myocardial blood flow are unknown.

METHODS

In a randomized, double-blind, crossover study we examined the effects of tadalafil, 20 mg, compared with placebo on myocardial blood flow in patients with stable coronary artery disease (n=7, 52-73 years old). After tadalafil or placebo, myocardial blood flow was measured with positron emission tomography (nine-segment model) at rest, during maximal coronary hyperemia with adenosine, and during increased myocardial work with dobutamine. Abnormal flow was defined as myocardial blood flow <75% of maximum perfusion during adenosine plus placebo (46 normal/17 abnormal segments dentified).

RESULTS

Compared with placebo, tadalafil had no significant effect on global myocardial blood flow at rest, during adenosine infusion, or during dobutamine infusion. Similarly, in normal and abnormal segments, tadalafil versus placebo had no significant effect on resting myocardial blood flow or on adenosine-induced increases in myocardial blood flow. In normal segments, myocardial blood flow with dobutamine plus tadalafil was greater than that with dobutamine plus placebo (1.79+/-0.56 versus 1.56+/-0.37 ml/g per min, P<0.01), and in abnormal segments, there was a trend for tadalafil compared with placebo to increase myocardial blood flow during dobutamine infusion (1.46+/-0.44 versus 1.36+/-0.36 ml/g per min, P=0.7).

CONCLUSIONS

Tadalafil had no significant effect on global myocardial blood flow at rest, during adenosine infusion, or during dobutamine infusion. Compared with placebo, tadalafil significantly augmented myocardial blood flow during increased workload in normal regions, with a trend toward improving myocardial blood flow in poorly perfused regions.

An Overview of the Diagnosis and Treatment of Erectile Dysfunction

Epidemiological studies have demonstrated an age-stratified increase in the incidence and prevalence of erectile dysfunction (ED). There is a greater degree of openness today when discussing sexual matters and more information on the treatment of ED is available to the public through the media. Quality-of-life issues are now a matter of great importance to the aging population. Men and their partners are no longer prepared to merely accept ED as a natural consequence of aging. The advent of a simple and effective oral therapy for ED has also indirectly fueled the increase in treatment-seeking behaviour among men. Despite great strides in research into ED, our knowledge and understanding of the pathophysiological mechanisms is still in its infancy. As a result, we are able to treat only the symptom of ED rather than prevent it. Common diseases found in the population, such as diabetes mellitus and coronary artery disease appear to be risk factors for the development of ED. Therefore, physicians need to identify any underlying co-existing organic diseases in their patients presenting with ED. Whenever possible, patients are encouraged to attend their consultation sessions with their partners because ED is a condition affecting 'the couple' and not just the man. Psychogenic aspects of ED should also be explored during the consultation. Efforts need to be made to uncover and address the presence of any psychological stressors, if necessary with the help of a psychosexual therapist. The first-line treatment of ED is oral phosphodiesterase-5 inhibitors. For those who do not respond to oral therapy, there is no defined 'step-ladder' escalation in alternative therapy. It is up to the physician to discuss the options with the patient or couple and reach a decision based on their preference.