Following the breakthrough in ED treatment using PDE5-inhibitors, Western medicine has now moved on to a new frontier of regenerative medicine, with stem cell and gene therapy leading the way (25). There is a practical need for novel therapy as a significant portion of diabetic or post-prostatectomy ED patients do not respond to oral pharmacotherapy. To date, stem cells derived from different sites including adipose tissue-derived stem cells, bone marrow mesenchymal stem cells and muscle-derived stem cells have been investigated using animal models for ED, to study their effects on neural, vascular, endothelial or smooth muscle regeneration (25,26).
Erection is a neurovascular event that involves spinal and supra spinal pathways. The final common pathway involves the release of nitric oxide (NO) from both endothelial cells and neurons, which acts as a vasodilator causing penile engorgement and erection. NO is degraded by the enzyme phosphodiesterase (PDE) type 5 in the penis. Erectile dysfunction (ED), defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance, results when the neurovascular pathway is interrupted by medical conditions or drugs. A 15-item self-administered questionnaire, the International Index of Erectile Function (IIEF), is one of the most useful tools to evaluate erectile function (EF) in clinical trials, although of much less use in routine clinical practice. The MMAS (Massachusetts Male Aging Study) was the first major epidemiological investigation to study the prevalence of ED. The study found that ED was three times more common in patients with diabetes mellitus. The aetiopathogenesis of ED in diabetes is multifactorial, with vascular and neural factors being equally implicated. Hyperglycaemia is believed to give rise to biochemical perturbations that lead to these microvascular changes. In the MMAS, ED in diabetes was strongly correlated with glycaemic control, duration of disease and diabetic complications. The incidence increased with increasing age, duration of diabetes and deteriorating metabolic control, and was higher in individuals with type 2 diabetes than those with type 1.ED in men with diabetes often affects their quality of life and, as patients are often reluctant to come forward with their symptoms, a carefully taken history is one of the most useful approaches in identifying affected individuals. The PDE inhibitors have revolutionised the management of ED and oral drug therapy is currently first-line therapy for the condition. These agents act by potentiating the action of intracavernosal NO, thereby leading to a more sustained erection. Sildenafil was the first PDE5 inhibitor to undergo evaluation and has been studied extensively. More recently two other agents, vardenafil and tadalafil, have been introduced. All the drugs have been shown to be effective across a wide range of aetiologies of ED, including diabetes. The drugs have been shown to improve EF domain scores, penetration and maintenance of erection, resulting in more successful intercourse. Their effects are greater at higher doses. Sildenafil and vardenafil are shorter-acting agents, while tadalafil has a longer half-life allowing the user more flexibility in sexual activity. Common adverse effects include headache, nasal congestion and dyspepsia, all actions related to inhibition of PDE5. The drugs are generally well tolerated and withdrawal from the clinical studies as a result of drug-related adverse effects were rare. The use of PDE5 inhibitors in the presence of oral nitrates is absolutely contraindicated. The clinical studies to date have not evaluated the use of one drug in the case of treatment failure with another agent. Sublingual apomorphine, which stimulates central neurogenic pathways, is a new agent and may be a suitable alternative in those patients in whom PDE5 inhibitors are ineffective or contraindicated. In clinical trials, all IIEF domains except sexual desire were found to have improved after apomorphine. The median times to erection in these studies were 18.9 and 18.8 minutes for the 2 and 3mg doses, respectively. Intraurethral and intracavernosal alprostadil may be a useful alternative when oral drug therapy is ineffective or contraindicated. The management of ED in the diabetic patient may often involve a multidisciplinary approach where psychosexual counselling and specialist urologist advice is required in addition to the skills and expertise of the diabetologist. Finally, the introduction of the new oral agents have completely revolutionised the management of ED and allowed more individuals to come forward for treatment.
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Abstract | Full Text | Full Text PDF | PubMed | Scopus (53) | Google ScholarSee all References Coital position has not been shown to play a role in increased cardiovascular risk; similar peak heart rates and blood pressure levels are evident with either the man or the woman in the superior position during intercourse.90x90Nemec, ED, Mansfield, L, and Kennedy, JW. Heart rate and blood pressure responses during sexual activity in normal males. Am Heart J. 1976; 92: 274–277
“I’m hoping this study will drive that (tie) a little bit harder and faster so that physicians will routinely be including ED when they’re screening patients for cardiovascular disease,” he said. “Doctors should ask the question and consider whether hardening of the arteries is occurring, ask about family history and signs or symptoms like chest pain with exertion, and spend the requisite amount of time to find out what’s going on.”
These drugs are safe for healthy hearts, but all men with cardiovascular disease should take special precautions, and some cannot use them under any circumstances. The problem is their effect on arteries. All arteries, not just those in the penis, generate nitric oxide, so any artery can widen in response to Viagra, Levitra, or Cialis, causing blood pressure to drop temporarily by 5-8 mmHg, even in healthy men.
Diabetes mellitus is associated with both decreased erectile function and increased cardiovascular risk. The MMAS found that the age-adjusted probability of complete impotence was 3 times higher in patients with diabetes mellitus than in those without the disease.6x6Kloner, RA. Erectile dysfunction and cardiovascular risk factors. Hosp Pract (Off Ed). 2001; 36: 41–44 (49-51.)
The safety of PDE5 inhibitors in patients with IHD has been shown in multiple trials. Arruda-Olson et al. investigated the safety of sildenafil during exercise stress tests in patients with IHD to ascertain whether the drug induces or exacerbates myocardial ischaemia. This was a prospective, randomised crossover study that demonstrated safety of sildenafil when given 1 hour before an exercise stress test.69 Another study that investigated 120 trials of sildenafil revealed that the rates of MI and cardiovascular death with sildenafil are as low as with placebo.70
Having chronically high blood pressure can affect overall satisfaction with sex and affect men’s ability to achieve a firm erection. Due to constant vessel damage as a result of high blood pressure, linings of the arteries begin to harden and narrow, a process called atherosclerosis. Because blood flow is limited to the affected regions of the body, arterial blood circulation to various organs—including the heart muscles, brain, and even the groin—can be compromised, with myocardial infarctions, strokes, and erectile difficulty being common in hypertensive patients. Studies show that approximately 30 percent of hypertensive patients reported having erectile dysfunction, and approximately 49 percent of men aged 40 to 79 had both high blood pressure and ED.
Ohlsson C,  Barrett-Connor E,  Bhasin S,  Orwoll E,  Labrie F,  Karlsson MK,  Ljunggren O,  Vandenput L,  Mellström D,  Tivesten A. High serum testosterone is associated with reduced risk of cardiovascular events in elderly men. The MrOS (Osteoporotic Fractures in Men) study in Sweden, J Am Coll Cardiol , 2011, vol. 58 (pg. 1674-1681)https://doi.org/10.1016/j.jacc.2011.07.019
When it comes to boosting sexual performance, many men will walk all over God’s green earth looking for ways to maintain a good sex life. Luckily men, all you have to do is walk — not run — 2 miles a day. This, along with other healthier lifestyle interventions can help obese men reduce their risk of ED, or even “reverse” current impotence, according to a 2005 study. This comes of importance, since maintaining a trim waistline is a good defense for ED, as men with a 42-inch waist are 50 percent more likely to have ED than those with a 32-inch waist. Getting to a healthy weight and maintaining it is a good strategy for preventing and treating ED.
Not enough info for you? No problem. Nerd out on erectile dysfunction with these studies and research from the most trusted sources on the interwebs. If you have any questions or you think we missed something important, leave a comment or book a consultation with me or one of these trained professionals and we’ll get you on the way to a healthier manhood.
Contraindications for TTh include (for detailed listing, please refer to Buvat et al.45) patients with breast or prostate cancer, while patients with a palpable prostate nodule or induration, or prostate-specific antigen >4 ng/mL (or >3 ng/mL in men at high risk for prostate cancer, such as African-Americans or men with first-degree relatives with prostate cancer), should first undergo urological evaluation. Testosterone therapy is contraindicated also in patients with haematocrit >50% (TTh increases haematocrit) and uncontrolled congestive heart failure (risk of fluid retention). Risk for adverse CVD events may be increased in patients and with the mode of treatment epitomized in the study of Basaria et al.46 (see earlier).
Despite the existing controversies, available data so far imply the old generation b-blockers (e.g., propranolol) as the major culprits for sexual dysfunction with the newer ones (carvedilol, celiprolol) to exert a less pronounced negative effect[21-24]. A luminous exception to the rule, nebivolol, is a newer agent of its class which significantly ameliorates erectile dysfunction through increased nitric oxide generation, an effect consistently demonstrated in recent studies[25,26]. Diuretics, even on adjunct therapy, constitute another antihypertensive agent negatively associated with sexual function[27-29]. On the other hand, calcium antagonists and angiotensin converting enzyme inhibitors seem to demonstrate a neutral effect[30-32]. Interestingly, angiotensin receptor blockers (ARBs) by blocking the vasoconstrictive action of angiotensin II seem to positively affect erectile function and are thus regarded as a first-line treatment in hypertensive patients with erectile dysfunction[22,25,33-35].
Abstract | Full Text | Full Text PDF | PubMed | Scopus (66) | Google ScholarSee all References However, some researchers have questioned whether the strain of sexual activity can be compared accurately with standard types of physical activity and whether sexual activity is more closely related to episodes of anger or fear.85x85DeBusk, RF. Evaluating the cardiovascular tolerance for sex. Am J Cardiol. 2000; 86: 51F–56F
David F. Penson, MD, MPH, is an associate professor of urology and preventive medicine in the Keck School of Medicine at the University of Southern California, in Los Angeles. Hunter Wessells, MD, is an associate professor of urology at the University of Washington School of Medicine and chief of urology at Harborview Medical Center in Seattle, Wash.
Levine GN,  Steinke EE,  Bakaeen FG,  Bozkurt B,  Cheitlin MD,  Conti JB,  Foster E,  Jaarsma T,  Kloner RA,  Lange RA,  Lindau ST,  Maron BJ,  Moser DK,  Ohman EM,  Seftel AD,  Stewart WJ. Sexual activity and cardiovascular disease: a scientific statement from the American Heart Association, Circulation , 2012, vol. 125 (pg. 1058-1072)https://doi.org/10.1161/CIR.0b013e3182447787
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.
There are two kinds of surgery for ED: one involves implantation of a penile prosthesis; the other attempts vascular reconstruction. Expert opinion about surgical implants has changed during recent years; today, surgery is no longer so widely recommended. There are many less-invasive and less-expensive options, and surgery should be considered only as a last resort.
More than 11 million people in the United States have cardiovascular disease, and each year, about 500,000 survive a myocardial infarction. These patients often seek counseling on their relative risk of resuming sexual activity. In the past, it was often assumed that if a patient could climb 2 flights of stairs without symptoms, it was safe for the patient to engage in sexual activity.82x82Hellerstein, HK and Friedman, EH. Sexual activity and the postcoronary patient. Arch Intern Med. 1970; 125: 987–999

Intracavernosal and intraurethral injections are second-line therapy for patients with ED. Alprostadil is the agent most commonly used for intracavernosal injections. The main adverse effects of intracavernosal injections are painful erection, priapism and development of scarring at the injection site.73 Alprostadil is also available as a topical cream in patients who cannot tolerate injections.75
Table 3Metabolic Equivalent (MET) Values for Various Physical Activities56x56Wallis, RM, Corbin, JD, Francis, SH, and Ellis, P. Tissue distribution of phosphodiesterase families and the effects of sildenafil on tissue cyclic nucleotides, platelet function, and the contractile responses of trabeculae carneae and aortic rings in vitro. Am J Cardiol. 1999; 83: 3C–12C
Abstract | Full Text | Full Text PDF | PubMed | Scopus (259) | Google ScholarSee all References Sildenafil should be used with caution in patients with liver dysfunction or renal impairment, as well as in patients taking any medications that inhibit the P-450 pathway such as cimetidine or erythromycin.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
Erne P,  Schoenenberger AW,  Zuber M,  Burckhardt D,  Kiowski W,  Dubach P,  Resink T,  Pfisterer M. Effects of anti-ischaemic drug therapy in silent myocardial ischaemia type I: the Swiss Interventional Study on Silent Ischaemia type I (SWISSI I): a randomized, controlled pilot study, Eur Heart J , 2007, vol. 28 (pg. 2110-2117)https://doi.org/10.1093/eurheartj/ehm273
As you get older, your risk of both ED and heart disease increases. But the connection between these conditions is stronger among younger men, according to the Mayo Clinic. If you experience ED under the age of 50, it’s more likely to be a sign of underlying heart problems. If you experience it after the age of 70, it’s much less likely to be linked to heart disease.
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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