PDE-5 inhibitors amplify the intacavernosal production of cGMP in response to nitric oxide. This is achieved through the inhibition of cGMP's breakdown by the enzyme, PDE-5. If the predominant abnormality in the individual EDDM patient is molecular, the higher tissue levels of cGMP will overcome these inhibitory factors and the patient will regain erectile function. If the physical structure (eg, the compliance) of the cavernosal tissue has been significantly compromised by apoptosis of smooth muscle or increased collagen deposits, restoration of erectile function will not be achieved. These structural changes explain the lower efficacy rates of PDE-5 inhibitors in EDDM than in the general population.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Sildenafil has a 4000-fold increased selectivity for PDE-5 over PDE-3, has negligible effects on heart rate, and has only a modest effect on blood pressure level in healthy persons, with an average systolic pressure decrease of 10 mm Hg with a single dose of 100 mg.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
Before Viagra hit the market in 1998, there was no proven treatment for erectile dysfunction that men could take in pill form. Doctors were interested in yohimbe, an herb that increases heart rate and blood pressure. Some doctors prescribed it to their patients in combination with other treatments for erectile dysfunction. Even then it was not a recommended treatment and is still not today. Studies have not proven that it works.
A deficiency of L-arginine, however, does not generally disrupt nitric oxide synthesis because L-arginine availability is not the rate-limiting step in this process. In fact, research over the past five years has identified an endogenous (occurs in the body naturally) inhibitor called “asymmetric dimethylarginine” or ADMA, an amino acid which blocks the production of nitric oxide. By acting as an L-arginine mimic, this damaging look-alike effectively elbows out L-arginine and pushes it off to the side in the biochemical pathway leading to the synthesis of nitric oxide. ADMA is relatively elevated in patients with hypertension, high levels of cholesterol, triglycerides, homocysteine and low-density lipoprotein (LDL), and low levels of high-density lipoprotein (HDL), as well as with aging itself. This inhibitor of nitric oxide synthesis may very well be the common factor shared by all of these abnormal conditions. Increased levels of this detrimental inhibitor (ADMA) block nitric oxide production, leading to endothelial dysfunction.

Diabetes mellitus (DM) is strongly associated with an increased risk of erectile dysfunction (ED), the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance, but this condition can be successfully treated in the majority of diabetes patients. ED is present in 32% of type 1 and 46% of type 2 DM patients. Several population- based studies of ED prevalence calculated the odds ratios for the association between ED and various chronic diseases. An odds ratio must be sufficiently greater than 1.0 to identify an increased risk. Diabetes has an odds ratio, ED risk multiplier of 4.1, compared with 1.7 for hyperlipidemia and 1.6 for hypertension. Erectile dysfunction in diabetes mellitus (EDDM) patients has been considered to have an organic etiology. Healthcare providers have long realized that ED can be the first symptom of DM.


PubMed | Google ScholarSee all References They evaluated 40 patients with coronary artery disease who underwent coronary artery catheterization and whose penile brachial index (PBI) was measured by Doppler ultrasonography. Although a positive correlation was noted between the PBI and the severity of coronary artery obstruction, the relationship was not strong. Also, the degree of PBI abnormality did not effectively stratify the patients according to the severity of their coronary artery blockage. This study concluded that the PBI used alone would not be an effective predictor of ischemic heart disease.
And diabetes affects more than the blood system. “Diabetes also results in nerve dysfunction and, in the penile shaft, [eventually] the muscle starts to atrophy and is replaced by scar tissue or collagen rather than smooth muscle. That’s the ultimate end result in men,” explains urologist Ajay Nehra, MD, professor of urology at the Mayo Clinic in Rochester, Minn. That scenario — damage to all the tissues that support your penis — is what could happen if you do not get and keep your diabetes under control.

A number of drugs are known to cause ED in patients with DM (Table 1). For example, many EDDM patients are on antihypertensive medications. Replacement of thiazides or beta-blockers with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may be sufficient to regain erectile ability.5 Furthermore, discontinuation of selective serotonin reuptake inhibitors, if these drugs are not essential for patient well-being, may be therapeutic. Careful monitoring following drug discontinuation will help to determine if ED is due to the medication or other underlying disorders. The benefits of continued drug therapy with these drugs should always be weighed against the likelihood of causing ED and impacting on the patient's QOL.
In men without cardiovascular disease, erectile dysfunction (ED) pills are very safe. The three rivals -- Viagra, Cialis, and Levitra -- have similar side effects, including headache, facial flushing, nasal congestion, diarrhea, backache, and, in a few Viagra or Levitra users, temporary impaired color vision (men with retinitis pigmentosa, a rare eye disease, should check with their ophthalmologists before using these medications).

"Just because there is evidence doesn't mean it's good evidence," says Andrew McCullough, MD, associate professor of clinical urology at New York University Langone Medical Center in New York City, and one of the original clinical investigators for the ED drug Viagra (sildenafil). "And before men with ED start down the naturopathic route, it's smart to make sure that there isn't some underlying medical condition that needs to be corrected." Moreover, it is estimated that 30 million American men have erectile dysfunction, and 70% of cases are a result of a potentially deadly condition like atherosclerosis, kidney disease, vascular disease, neurological disease, or diabetes. Additionally, ED can also be caused by certain medications, surgical injury, and psychological problems.


Conversely, and of significant clinical importance, is how often patients with ED as their first and sole clinical manifestation suffer from subclinical CAD.17 Previous studies reported a rate of inducible ischaemia by exercise stress testing (EST) in 22% (with a wide range of 5–56%) of ED patients reflecting differences in patient population, risk factors and criteria used for ED and CAD diagnosis. Interestingly, those patients further assessed with coronary angiography had obstructive atherosclerosis in >90% of cases.4,18 In a prospective angiographic study, we documented that 19% of ED patients suffer from clinically silent obstructive CAD.18

Montorsi F,  Briganti A,  Salonia A,  Rigatti P,  Margonato A,  Macchi A,  Galli S,  Ravagnani PM,  Montorsi P. Erectile dysfunction prevalence, time of onset and association with risk factors in 300 consecutive patients with acute chest pain and angiographically documented coronary artery disease, Eur Urol , 2003, vol. 44 (pg. 360-364)https://doi.org/10.1016/S0302-2838(03)00305-1


Characteristics that imply a higher risk is severe ED (SHIM 1–7) and ED duration >3 years.15,30 Vascular and circulating biomarkers may help to characterize further the patient with ED.23 Of the wide array of biomarkers that have been proposed for the assessment of cardiovascular risk in asymptomatic adults,34,35 some have been studied specifically in the context of ED.23Table 4 offers a critical evaluation of these biomarkers. Such tests should be considered as potentially helpful and thus recommended where available, but not mandatory.30 Despite its potent predictive ability recently shown,36 exposure to radiation with coronary artery calcium scoring should be carefully weighed. Although not specific for ED, it might be reasonable to evaluate biomarkers that have been proposed for the intermediate-risk patient such as uric acid, glycated haemoglobin, microalbuminuria, and lipoprotein-associated phospholipase A2.30
Normal male sexual function requires a complex interaction of vascular, neurological, hormonal, and psychological systems. The initial obligatory event is acquisition and maintenance of an erect penis, which is a vascular phenomenon. Normal erections require blood flow into the corpora cavernosae and corpus spongiosum. As the blood accelerates, the pressure within the intracavernosal space increases dramatically to choke off penile venous outflow. This combination of increased intracavernosal blood flow and reduced venous outflow allows a man to acquire and maintain a firm erection.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (66) | Google ScholarSee all References Although some case studies have reported a relationship between calcium channel blockers and ED, most studies suggest that this effect is minimal and that any relationship is likely secondary to a decrease in blood pressure with consequent reflex sympathetic activation.42x42Weiss, RJ. Effects of antihypertensive agents on sexual function. Am Fam Physician. 1991; 44: 2075–2082

Your choice of blood pressure medications could make a difference in the bedroom (or wherever you like to have sex). Thiazides (diuretics or “water pills”) and beta blockers are the most likely to cause erectile dysfunction (ED), while alpha blockers the least likely. Alpha blockers work by reducing nerve impulses to blood vessels, allowing blood to pass more easily. Ask your doctor whether these or other blood pressure medications are best for you.


Montorsi P,  Ravagnani PM,  Galli S,  Rotatori F,  Veglia F,  Briganti A,  Salonia A,  Dehò F,  Rigatti P,  Montorsi F,  Fiorentini C. Association between erectile dysfunction and coronary artery disease. Role of coronary clinical presentation and extent of coronary vessels involvement: the COBRA trial, Eur Heart J , 2006, vol. 27 (pg. 2632-2639)https://doi.org/10.1093/eurheartj/ehl142
The impact of third-generation cardioselective beta-blockers such as carvedilol and nebivolol has also been investigated. Fogari et al. investigated the effect of carvedilol on erectile function in a double-blind crossover study involving 160 men newly diagnosed with hypertension and found chronic worsening of sexual function in those treated with carvedilol compared with valsartan and placebo.24
An equally valuable observation though, is the fact that sexual dysfunction could indeed indicate asymptomatic CV disease. A solid amount of evidence accumulated over the last years has pointed out towards that trend moving, hesitatingly though, sexual dysfunction in the surface of scientific interest. As such, commonly under-reported, under-recognized and under-treated, sexual dysfunction could indeed play its role in cardiovascular risk assessment and stratification.
** Indeterminate risk patients include diabetics, those with mild or moderate stable angina pectoris, past myocardial infarction (2-8 wks) without intervention awaiting exercise electrocardiography, congestive heart failure (NYHA class III), and noncardiac sequelae of atherosclerotic disease (eg, peripheral artery disease and a history of stroke or transient ischemic attack); this patient with ED may require assessment for additional vascular disease using carotid intima-media thickness or ankle-brachial index and subsequent reclassification to low or high risk.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

A component of the increased risk conferred by ED could be testosterone deficiency.24 Low testosterone leads to increased levels of total and LDL cholesterol, as well as to increased production of pro-inflammatory markers and mediators.25 Endothelial dysfunction and increased arterial wall thickness, stiffening, and calcification also ensue. On this basis it has been hypothesized that chronically lowered testosterone may increase CVD risk. Indeed, androgen deficiency has emerged as a predictor of CV events, as well as of all-cause and CV mortality, both in the general population and in patients with CV risk factors, with hypertension, with established CVD, and with ED.26 Viewed from the opposite angle, higher serum testosterone showed a protective role for CV events in elderly men.27 A 2010 meta-analysis limited to studies in middle-aged men found no association between total testosterone (TT) levels and CVD risk.28 However, a more recent meta-analysis involving a larger number of studies identified significant associations between androgen deficiency and increased risk of CVD and CVD mortality.29 It should be stressed, however, that the nature of these studies cannot prove causality. The possibility that low testosterone may be an epiphenomenon, marking poor general health rather than modulating CVD risk per se has to be explored.


Cardiovascular disease and ED represent 2 common disease processes that are often intimately associated with one another. These common pathophysiological links necessitate a solid scientific and clinical understanding of these 2 disorders and a team effort between the cardiologist and urologist to provide effective management strategies for these patients.
Impotence, also called erectile dysfunction (ED), can be a very frustrating problem. Some men are able to achieve an erection but are not able to maintain one. Others are not able to achieve one at all. Causes of impotence can be both physiological (affecting mostly the body and organs) or psychological (affecting the mind). Luckily, there are natural remedies for impotence you can try.
Having ED means that all, most, or some of the time, the penis fails to become or stay hard enough for sexual intercourse. If, on rare occasions, you cannot get an erection, you do not have ED. You also do not have ED if you have a decrease in sexual desire, have premature ejaculation, or if you fail to ejaculate or reach orgasm. ED means that you can’t get or keep an erection.

The first step in the process is always to reevaluate if the medication that’s causing the problem is even necessary in the first place. Do you still need the medication(s) that you’re taking? When you’re experiencing medically induced ED, this has to be your starting point. Obviously you shouldn’t make this decision on your own. However, reevaluating your need for medication can be a simple conversation with your doctor. Remind your healthcare provider of the medications you’re taking, and explain any symptoms or side effects—like ED. Going off of medication might sound like an extreme step, but I’ve seen many examples of this in practice.

In some cases, however, these drugs may be unsuitable for patients with heart disease. If you are considering one of these drugs and you have heart disease, as many diabetics do, be sure to tell your doctor. In rare cases, the pills may create “priapism,” a prolonged and painful erection lasting six hours or more (although reversible with prompt medical attention).
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