Sexual dysfunction refers to a problem during any phase of the sexual response cycle that prevents the individual or couple from experiencing satisfaction from the sexual activity. The sexual response cycle has four phases: excitement, plateau, orgasm, and resolution. Sexual dysfunction can be caused by physical and emotional factors, or a combination of both. The side effects of some medications also can lead to sexual dysfunction.
For those patients who cannot take erectile dysfunction medications, the authors counsel that an exercise training regimen may be an appropriate substitute therapy to enhance sexual function and quality of life. The authors stress that clinicians should focus on the sexual activity history of chronic heart failure patients and not ignore it, since addressing this element can substantially improve their quality of life.

The aetiology of predominantly psychogenic ED is multifactorial, and components may include psychiatric disorders (especially depression), interpersonal problems with the sexual partner or misconceptions about normal sexual activity. Identifying and getting treatment for those patients with psychogenic causes of ED such as depression that may also increase CVD risk is also important.


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).
Artery size also explains the onset of ED before occurrence of CAD. Coronary arteries are 3–4 mm in diameter, while the penile artery is 1–2 mm in diameter.17 Endothelial dysfunction and plaque burden in the small arteries may cause symptoms of ED before they affect blood flow in large arteries. Also, an asymptomatic lipid-rich plaque in the coronary arteries carries the risk of rupture that leads to acute coronary syndrome or death, so ED may be predictive of these serious events without warning cardiac symptoms.17
Beta-blockers: A popular blood pressure medication that affects part of the nervous system in an attempt to slow and regulate heartbeats, helping reduce blood pressure. Unfortunately, this same part of the nervous system is also responsible for causing erections, and when beta blockers are used, it indirectly reduces the amount of blood flow to the penis.
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.
* Low-risk patients include those with complete revascularization (eg, via coronary artery bypass grafting, stenting, or angioplasty), patients with asymptomatic controlled hypertension, those with mild valvular disease, and patients with left ventricular dysfunction/heart failure (NYHA classes I and II) who achieved 5 metabolic equivalents of the task METS without ischemia on recent exercise testing.
Experimental hyperglycemia may also affect cavernosal smooth muscle cell contractile responses. In experimental diabetes, penile smooth muscle has augmented force responses to vaconstrictors, possibly mediated by changes in expression of protein kinase C and the RhoA-Rho kinase Ca2+-sensitization pathway.32 These changes may promote flaccidity and alter the relaxation responses to nitric oxide. End-stage penile dysfunction may occur as a result of diabetes, with progressive loss of normal cavernosal endothelium and smooth muscle cells from the corpus cavernosum.33 Replacement by fibrotic tissue may lead to complete erectile failure.34
The body’s source for nitric oxide production is the amino acid L-arginine, which is naturally found in many foods. The average American ingests about 3,000–5,000 mg of L-arginine per day, as it is an amino acid naturally contained in many foods. Meats of all varieties, nuts, and dairy products are rich in L-arginine, so the body is accustomed to intake levels of several thousand milligrams every day.
Neelima V. Chu, MD, is an endocrinology fellow in the Division of Endocrinology and Metabolism at the University of California, San Diego. Steven V. Edelman, MD, is an associate professor of medicine in the Division of Endocrinology and Metabolism at the University of California, San Diego, and the Division of Endocrinology and Metabolism at the San Diego VA Health Care Systems in San Diego. He is founder and director of Taking Control of Your Diabetes, a nonprofit organization, and an associate editor of Clinical Diabetes.

Some doctors prefer to start a man on the lowest dose of an oral medicine and increase the dose until an effective one is found. Others prefer to start with the highest dose and go to a lower dose only if a man complains of side effects. In either case, it’s important for a man to communicate with his doctor to let him know how the dose he’s using is working.
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