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.


DHEA. Testosterone is essential for a healthy libido and normal sexual function, and erectile dysfunction sufferers known to have low testosterone improve when placed on prescription testosterone replacement therapy. Similarly, studies have shown that taking over-the-counter supplements containing DHEA, a hormone that the body converts to testosterone and estrogen, can help alleviate some cases of ED. But DHEA can cause problems, including suppression of pituitary function, acne, hair loss and its long-term safety is unknown, says McCullough. For this reason, many experts discourage use of the supplements.
There are so many potential reasons a man might develop erectile dysfunction (ED), it's nearly impossible to generalize the best ways to treat it. What works for one man may not work for another simply because they are having problems for different reasons. That said, it may encouraging to hear that there are a variety of options that may be considered, from psychological counseling to lifestyle changes, medications to treatments and devices.
The Epimedium plant is a flowering perennial found throughout Asia and parts of the Mediterranean. Horny Goat Weed’s active ingredient is icariin, a falvonol glycoside and reputed to improve cardiovascular function, hormone regulation, modulation of immunological function and antitumor activity (44). Icariin has also been shown to have a PDE5i effect. Animal studies have been carried out showing improvements in penile hemodynamic parameters. There is one report of tachyarrhythmia and hypomania with the use of this herb (45).
If your physician advises you that the risks of taking an erectile dysfunction medication are too high, he or she can advise you of other treatment options that can enable you to resume sexual activity without risks of complications. These might also include screening to try to determine if your erectile dysfunction has a physiological basis in need of medical intervention, can be corrected through lifestyle changes or if it may have psychological roots. After all, a heart attack or diagnosis of heart disease can lead to depression, which can also affect libido. Talk with your doctor to establish a safe, effective plan for resuming intimacy after your heart disease diagnosis.
After the initiation of TTh patients should be evaluated at 3 and 6 months, and annually thereafter to assess response to treatment and monitor adverse effects. Assessment should include physical examination with particular attention to the prostate. At these intervals testosterone levels should also be monitored, as well as PSA, haematocrit, and HDL.45
Medications used in the treatment of cardiovascular disease, especially antihypertensive medications, have been implicated frequently in the development of sexual dysfunction. A study of 5485 patients in the Hypertension Detection and Follow-up Program found that, during a 5-year period, 8.3% of male hypertensive patients stopped taking their antihypertensive medications secondary to sexual adverse effects.35x35Curb, JD, Borhani, NO, Blaszkowski, TP, Zimbaldi, N, Fotiu, S, and Williams, W. Long-term surveillance for adverse effects of antihypertensive drugs. JAMA. 1985; 253: 3263–3268

Abstract | Full Text | Full Text PDF | PubMed | Scopus (24) | Google ScholarSee all References Withdrawal of sexual stimulation causes a return of sympathetic tone and degradation of cGMP, predominantly by phosphodiesterase type 5 (PDE-5) within the trabecular smooth muscle.11x11Nehra, A. Intracavernosal therapy: when oral agents fail. Curr Urol Rep. 2001; 2: 468–472
In years past, before nitric oxide and its role in the erectile response was appreciated, testosterone was used to treat sexual dysfunction in men. It proved a partial success as a standalone therapy, resulting in improved erectile potency in 40–60% of men with low-to-normal testosterone levels. The likelihood of success increased, however, if starting testosterone levels were low (usually defined as below 300 ng/dL), in which case improved erections were experienced by as many as 65% of men, compared with 16.7% receiving placebo; topical testosterone preparations were also noted to be superior to oral replacement or injections.21 These findings were confirmed by another study that showed testosterone produced modest improvements in erectile function and libido in men with low-to-normal testosterone levels.22
What comes after an ED diagnosis in diabetic patients? Often, Dr. Eid will instantly refer these men to a cardiologist. “If a patient has diabetes and is newly diagnosed, a significant portion of these men are going to develop coronary artery disease in the next 2-3 years,” he said. “One of the things we do is recommend is that they see a cardiologist and perhaps have a stress test or some sort of evaluation.”
Penile arterial supply (top) and venous drainage (middle), longitudinal views. Bottom, Transverse and longitudinal views of venous return. From Lue TF. Physiology of penile erection and pathophysiology of erectile dysfunction and priapism. In: Walsh PC, Retik AB, Vaughan ED Jr, Wein AJ, eds. Campbell's Urology. Vol 2. 7th ed. Philadelphia, Pa: WB Saunders Co; 1998:1157-1179. With permission from Elsevier.

Yes, and there’s the rub. High blood pressure, especially if untreated, can lead to erectile dysfunction (ED). So can medications your doctor prescribes to bring down your high blood pressure. Fortunately, not all meds cause ED. Thiazides, diuretics or “water pills,” are common ED culprits. So are beta blockers. These effective heart meds slow your system down, and also affect blood flow where you need it -- in your penis -- at the right time. Alpha blockers, another class of medications that lower high blood pressure, are less likely to cause ED. So talk with your good doc about medication choices and side effects, so you can choose the right med for you.
Ginkgo Biloba is promoted to treat conditions ranging from hypertension to Alzheimer’s dementia. There is evidence that shows improvement of memory enhancements in the geriatric population (47), improvement in terms of cognitive function via effect on cerebral vasculature (48), improvement of claudication distance and cutaneous ulcers in patients with peripheral vascular disease (49). Ginkgo Biloba extract is proposed to induce NO in endothelial cells and thus causing relaxation of vascular smooth muscles. Animal studies have reported relaxation of rabbit corpus cavernosal smooth muscle cells with the use of Ginkgo Biloba (50). Adverse effects include headaches, major bleeding (in patient who are taking warfarin concurrently) and seizures with reported fatality (36).

In Western medicine approach, health and disease are clearly divided entities. The emphasis is on protection of the individual body from disease or how to replace the body’s lost functions. Antibiotic therapy is used to combat harmful bacteria during infections, exogenous synthetic hormones are used to replace hormone-deficient individuals and artificial prostheses are applied when an organ loses its functions. This is very different from the holistic Eastern approach where the treatment entity is taken as a whole, and the objective is to seek harmony between different bodily systems.

Normal penile erection is controlled by two mechanisms: reflex erection and psychogenic erection. Reflex erection occurs by directly touching the shaft of the penis, while psychogenic erection occurs by erotic or emotional stimuli. ED is a condition where erection does not take place by either mechanism. ED can occur because of hormonal imbalance, neural disorders or lack of adequate blood supply to the penis.54 Lack of blood supply can be a result of impaired endothelial function associated with CAD.54

Co-authors Stacy Mandras, M.D., Patricia Uber, Pharm. D., and Mandeep Mehra, M.D., conducted systematic independent literature searches using the MEDLINE database and examined a broad range of medical research that focused on chronic heart failure, sexual activity and sexual dysfunction. This literature included data from patient surveys and clinical trials.
While all three forms of male sexual dysfunction can be found among diabetic men, this review will focus on the most common form, ED, because the literature is most mature in this area. Defined as the inability to achieve or maintain an erection sufficient for satisfactory sexual performance, ED is highly prevalent in diabetic men1 and is almost always organic in its etiology. Given that many patients feel that their ED is “in their heads” and that “their provider will dismiss any sexual problems they might bring up,”2 it may be a relief for patients to learn that their ED is physical, related to their diabetes, and treatable. To this end, the goal of this article is to review the epidemiology, pathophysiology, quality of life effect, and treatment of ED in men with type 2 diabetes.
A recent systematic review and meta-analysis of relevant studies in this field confirmed that erectile dysfunction is associated with increased risk of CV events and all-cause mortality[89]. The pooled relative risks were 1.44 (95%CI: 1.27-1.63) for total CV events, 1.19 (95%CI: 0.97-1.46) for CV mortality, 1.62 (95%CI: 1.34-1.96) for myocardial infarction, 1.39 (95%CI: 1.23-1.57) for cerebrovascular events, and 1.25 (95%CI: 1.12-1.39) for all-cause mortality, for men with vs without erectile dysfunction. Of note, the relative risk was higher in intermediate-compared with high- or low-CV-risk populations and with younger age, with obvious clinical implications. Interestingly, the relative risks were higher when erectile dysfunction was diagnosed with the use of a questionnaire compared with a single question (RR = 1.61; 95%CI: 1.38-1.86 vs RR = 1.27; 95%CI: 1.18-1.37, respectively; P = 0.006).
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Phase 2 and 3 trials reported minimal associated cardiac adverse effects, which occurred in 3% of patients taking sildenafil and in 3.5% of patients receiving placebos.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
The number of men reporting improvement was at 88% during the study. The number of men involved in the study who reported impotence dropped from 75.3 % to 11.8%. The results of this study raise hope for men who have quit taking other blood pressure medications because they interfered with sexual function. Sexual dysfunction was defined for the study as decreased libido, impotence and poor sexual satisfaction.

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
The initial event for normal erectile function is sexual stimulation. Subsequent to processing in the central nervous system neural impulses are conveyed along the spinal cord, exiting through the pelvic parasympathetic preganglionic nerves. These pelvic nerves form the pelvic plexus and send their message through first messenger, acetyl choline, to the cavernosal nerves. The cavernosal nerves enter erectile bodies (corpora cavernosa) (Figure 1). Here, their nerve endings release a second messenger, nitric oxide. Nitric oxide activates the enzyme guanylyl cyclase, which lyses guanosine triphosphate (GTP) to produce a third messenger, the intracellular cyclic guanosine monophosphate (cGMP). Ultimately, the result is a decrease of intracellular calcium and an opening of potassium channels with the resultant relaxation of vascular smooth muscle in the arteries, aterioles, and sinusoids of the corpora cavernosa. The sinusoids open and rapidly fill with blood. Finally, the distended sinusoids compress their drainage pathways (venules) against the fibroelastic covering of the cavernosal bodies (tunica albuginea) and trap the blood in cavernosal bodies. The combination of an increased inflow of blood into the penis and coincident markedly diminished outflow results in rapidly increasing intracavernosal pressure that ultimately approximates systolic pressure. At this pressure the penis has sufficient axial rigidity to permit vaginal penetration.

The study, which retrospectively tracked more than 43,000 men for an average of 3.3 years, found that men prescribed phosphodiesterase-5 (PDE5) inhibitors—the type of erectile dysfunction drug sold under the names Viagra, Levitra, Cialis and others—after their first heart attack were 38 percent less likely to die from any cause. No survival benefit was seen among men taking alprostadil, another type of erectile dysfunction drug that works through a different mechanism.
Crossref | PubMed | Scopus (539) | Google ScholarSee all References Aside from the economic costs, ED can have severe psychological effects, resulting in poor self-image, decreased self-esteem, depression, and mental stress, and negative effects on personal relationships.2x2NIH Consensus Development Panel on Impotence. NIH Consensus Conference: impotence. JAMA. 1993; 270: 83–90
Crossref | PubMed | Google ScholarSee all References In study patients taking these medications compared with controls, significant decreases in total cholesterol and low-density lipoprotein cholesterol levels were found, as well as significant increases in length of maximal tumescence per nocturnal penile tumescence testing at 2 weeks. Hypoglycemia secondary to the use of insulin or hypoglycemic agents may result in ED or orgasmic dysfunction.4x4Feldman, HA, Goldstein, I, Hatzichristou, DG, Krane, RJ, and McKinlay, JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994; 151: 54–61
Smoking is an independent risk factor for ED. Tobacco smoking causes direct toxicity to endothelial cells, including decreased eNOS activity, increased adhesion expression and impaired regulation of thrombotic factors.6 A meta-analysis of 19 studies by Tengs and Osgood suggested that 40 % of the impotent men studied were current smokers compared with 28 % who had never smoked.49
Currently, the preferred treatment for erectile dysfunction includes sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis). However, numerous experts have raised concerns about the use of these drugs in patients with chronic heart failure who also take nitrates (or other medications that relax and widen blood vessels). This drug combination has been shown to be dangerous, because it can increase the risk for a life-threatening drop in blood pressure.

The development of PDE5-inhibitors is a clear example of how Western medicine approached the problem of ED differently from Eastern medicine. The erectogenic effect of sildenafil (Viagra®) was discovered by accident when patients undergoing heart clinical trials reported better erections as a side effect after taking sildenafil. This observation led to further elucidation of the NO/cGMP signalling pathway and development of PDE5-inhibitors as a first-line therapy in ED (5).
In a 2005 study, three months of twice-daily sets of kegel exercises combined with biofeedback and advice on lifestyle changes, such as quitting smoking, losing weight, and limiting alcohol, worked far better than just giving the participants advice. “Wearing tight pants will affect impotence along with some other medical conditions like diabetes and heart disease,” which can also affect a man’s degree of impotence, Dr. Jennifer Burns, specializing in family practice with an emphasis on gastrointestinal health at the BienEtre Center, told Medical Daily.
Talk with your doctor about your sexual health. Do not be shy or embarrassed. Your doctor has probably dealt with this issue before. If your doctor is an older man, he might even have ED. First, your doctor will figure out what is causing your ED, which can usually be done just by talking with you. Next, your doctor will look for risk factors for atherosclerosis (the Table) by asking you questions, checking your blood pressure, and performing a few blood tests. Identifying and successfully treating atherosclerotic risk factors can reduce the chance of developing major vascular events (heart attacks and strokes).
Physical and emotional stress — whether over-exercising, under-sleeping or just dealing with everyday stressors like work and a busy schedule — causes an increase in “stress hormones,” including cortisol and adrenaline. Stress can lower desire for sex. This is because stress can contribute to fatigue or preoccupation with other tasks. It can also significantly affect blood flow by increasing inflammation.
Since time immemorial, TCM has been adopted by many cultures and is widely practiced in Asian countries despite paucity of level 1 clinical evidence and limited published safety records. TCM is more congruent with Asian values, beliefs and philosophical orientation to health, simple administration, readily available and ease of access or procurement, and general belief that TCM is safer. While Asian males are clearly different from their Western counterparts with respect to biology, culture and beliefs, the practice of TCM appears to be adopted by many Western nations lately. Many men seek TCM to avoid embarrassing visits to physicians and potential side effects of pharmaceutical drugs, or after becoming frustrated with the outcome of modern medicine. Patients are choosing to take more responsibility for their health by exploring a variety of non-pharmaceutical drugs and wellness practices. Furthermore, TCM such as herbal medicine does not address a specific organ system only and is meant to restore and realign the vital energy within the body, which is responsible for ageing, clinical diseases and the deterioration of bodily function; while in Western medicine, each pill is intended for a specific organ/system and that a patient may need a collection of pills to treat multiple comorbidities, rendering modern medicine less attractive to TCM.
There are so many potential reasons a man might develop erectile dysfunction (ED), it's nearly impossible to generalize the best ways to treat it. What works for one man may not work for another simply because they are having problems for different reasons. That said, it may encouraging to hear that there are a variety of options that may be considered, from psychological counseling to lifestyle changes, medications to treatments and devices.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (58) | Google ScholarSee all References Theoretically, the risk of a cardiac event during sexual activity should be increased. Sexual activity is associated with an elevated heart rate, blood pressure level, and myocardial oxygen demand, and this increase in hemodynamic stress may result in myocardial ischemia.79x79Kimmel, SE. Sex and myocardial infarction: an epidemiologic perspective. Am J Cardiol. 2000; 86: 10F–13F

Abstract | Full Text | Full Text PDF | PubMed | Scopus (30) | Google ScholarSee all References Erections result from relaxation of the corpora cavernosa, which is mediated either by increasing intracellular cyclic guanosine monophosphate (cGMP) or cyclic adenosine monophosphate or by inhibition of their degradation. Increased parasympathetic tone results in a decrease in norepinephrine release and an increase in the release of acetylcholine; subsequently, NO synthase activity increases, which releases NO from both endothelial cells and nonadrenergic, noncholinergic neurons.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N


Ginseng. Korean red ginseng has long been used to stimulate male sexual function, but few studies have tried systematically to confirm its benefits. In one 2002 study involving 45 men with significant ED, the herb helped alleviate symptoms of erectile dysfunction and brought "enhanced penile tip rigidity." Experts aren't sure how ginseng might work, though it's thought to promote nitric oxide synthesis. "I would recommend ginseng [for men with ED]," says Espinosa. Discuss with your doctor before taking it since ginseng can interact with drugs you may already be taking and cause allergic reactions.
Eastern medicine should be fully exploited, and integrated with modern medicine to combine the advantages of both TCM and Western medicine. More research should be conducted into the efficacy and safety of TCM, and integration of TCM and Western medicine may provide promising breakthroughs in future clinical treatment. This strategy may allow for the development of new therapeutic strategies based on concepts of TCM and integrated medicine. There is a need for multimodal therapy and holistic approach to treat men (and their partners) with ED through complementary use of herbal supplements and modern drug to optimize underlying medical comorbidities; acupuncture, exercise or massage to reduce stress and strengthen the body; introduction and escalation of various medical therapy with use of mechanical therapy to further enhance penile erection; and lastly surgical intervention in suboptimal or refractory ED cases.
Other factors that “stress” the body can also increase your risk for ED. These include: substance abuse, using marijuana, smoking cigarettes, depression, anxiety and low self esteem. Cigarette smoking — or using nicotine — leads to constricted blood vessels, which has negative effects for sexual health. Other mental/emotional obstacles can cause less desire for sex and decrease testosterone. Several ways to help manage stress include:
Yohimbine is an indole alkaloid derived from the bark of the African yohimbe tree (33). Yohimbine has been noted to treat fatigue, depression, diabetes, and sexual dysfunction. A meta-analysis of seven placebo-controlled trials (34) deemed yohimbine superior to placebo for the treatment of ED with rare adverse events. The proposed mechanism of action (35) is via the inhibition of central alpha-2-adrenergic receptors, decreasing central inhibition of arousal, and increasing penile nerve stimulation resulting in increased NO. Common side effects include headache, sweating, agitation, hypertension and insomnia. Contraindications include patients on tricyclic antidepressants, anti-hypertensives and central nervous system stimulants.
Whereas management of sexual dysfunction in previously untreated hypertensive patients can be a challenging procedure, confronting the same clinical condition in individuals under antihypertensive regime can be even more demanding. In such cases there will always be a question hovering over physicians head. Is hypertension per se, antihypertensive medication or both, the causative factors provoking sexual dysfunction[15]?
Erectile dysfunction is a common occurrence in men with diabetes. The incidence of erectile dysfunction increases progressively with age, from 5% in men age 20 to 75% in men over age 65. The cause of erectile dysfunction in men with diabetes is usually related to a decrease in the blood supply to the penis as well as to injury to the nerves that are responsible for the erection mechanism. A decrease in testosterone production has also been identified as the cause in some men with diabetes.
×