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.
There are a number of reasons a man may not achieve the desired result from an oral erectile dysfunction drug. In some cases, a man may experience drug side effects severe enough to outweigh any potential benefit of taking the drug. Possible side effects of these drugs include headache, facial flushing, nasal congestion, and transient abnormal vision. (In October 2007, the FDA added a warning about sudden hearing loss to the package labels of oral erectile dysfunction drugs. While it’s not absolutely clear that the drugs can cause sudden hearing loss, a number of cases have been reported in men within hours or days of taking one of the drugs.)
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
Causes of ED may be of primary developmental origin or secondary. Lack of sex hormone in the early developmental stage of male children is the major cause of primary ED. The secondary cause of ED involves arteriosclerosis, diabetes or psychogenic disturbances. Other secondary factors may include hypertension, hyperlipidaemia, obesity and tobacco use. The primary causes of ED are beyond the scope of this review; we will not be discussing the neurovascular mechanisms pertaining to ED and will focus on the relationship between IHD and ED.
Crossref | PubMed | Scopus (335) | Google ScholarSee all References Glycemia, as measured by glycosylated hemoglobin, also has been associated with the risk of developing ED in diabetic patients.21x21Klein, R, Klein, BE, Lee, KE, Moss, SE, and Cruickshanks, KJ. Prevalence of self-reported erectile dysfunction in people with long-term IDDM. Diabetes Care. 1996; 19: 135–141
Lindau ST,  Abramsohn E,  Gosch K,  Wroblewski K,  Spatz ES,  Chan PS,  Spertus J,  Krumholz HM. Patterns and loss of sexual activity in the year following hospitalization for acute myocardial infarction (a United States National Multisite Observational Study), Am J Cardiol , 2012, vol. 109 (pg. 1439-1444)https://doi.org/10.1016/j.amjcard.2012.01.355
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).
It is recommended that testosterone be measured in patients with ED because low levels are a reliable measure of hypogonadism. Hypogonadism is not only a treatable cause of ED, but can also lead to reduced or lack of response to PDE5 inhibitors.73 Testosterone deficiency is also associated with increased cardiovascular and all-cause mortality.74 Levels >350 ng/dl do not usually require replacement, but in patients with testosterone <230 ng/dl, replacement can usually be beneficial.57 In patients with congestive heart failure, testosterone replacement can lead to fluid retention, so caution is advised. In these patients, the aim should be to keep testosterone levels in the middle range, i.e. 350–600 ng/dl.57

Since 1998, when sildenafil (brand name Viagra) first came on the market, oral therapy has been successfully used to treat erectile dysfunction in many men with diabetes. (Sildenafil was followed in 2003 by the drugs tadalafil [Cialis], vardenafil [Levitra] and avanafil [Stendra], which work in much the same way.) Some 50% of men with Type 1 diabetes who try the drugs report improved erections, and some 60% men with Type 2 diabetes do, too. However, that leaves a large percentage of men with diabetes and erectile dysfunction who do not respond to therapy with one of these pills. This article takes a look at what can be done to treat those men who do not respond to oral therapy.
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