Erectile dysfunction may be the result of arterial and non-arteritic causes. Hardening of the arteries that bring blood into the penis, atherosclerosis, is a common cause of erectile dysfunction, particularly in men with cardiovascular disease. However, problems with the nerves that supply the penis as well as the veins that drain blood out of the penis can also cause troubles with erection. Erectile dysfunction may also have a psychological cause.
Erectile dysfunction is the inability to develop or maintain an erection that is rigid enough to allow penetration of the vagina, and therefore functional sexual intercourse. Generally, the term erectile dysfunction is applied if this occurs frequently (75% of the time) over a significant period if time (several weeks to months). If this is the case, the term impotence may also be used.
Sildenafil (Viagra) was the first oral phosphodiesterase type 5 (PDE5) inhibitor approved by the FDA in the United States for the treatment of erectile dysfunction (it is not approved for women). Sildenafil inhibits PDE5, which is an enzyme that destroys cGMP. By inhibiting the destruction of cGMP by PDE5, sildenafil allows cGMP to accumulate. The cGMP in turn prolongs relaxation of the smooth muscle of the corpora cavernosa. Relaxation of the corpora cavernosa smooth muscle allows blood to flow into the penis resulting in increased engorgement of the penis. In short, sildenafil increases blood flow into the penis and decreases blood flow out of the penis.
An occasional problem achieving an erection is nothing to worry about. But failure to do so more than 50% of the time at any age may indicate a condition that needs treatment. About 40% of men in their 40s report at least occasional problems getting and maintaining erections. So do more than half (52%) of men aged 40 to 70, and about 70% of men in their 70s.
Inflatable prostheses are complex mechanical devices that imitate the natural process of erection. Parts are inserted surgically into the penis and scrotum, and activated by squeezing. When erection is no longer desired, a valve on the pump is pressed, and the penis becomes flaccid. Self-contained single-unit prostheses are similar to the inflatable types, but more compact. The entire device is implanted into the penis. When erection is desired, the unit is activated by either squeezing or bending, depending on which of the two types of self-contained prostheses is used.
Erectile dysfunction is defined as the persistent inability to achieve or maintain penile erection sufficient for satisfactory sexual performance. The Massachusetts Male Aging Study surveyed 1,709 men aged 40–70 years between 1987 and 1989 and found there was a total prevalence of erectile dysfunction of 52 percent. It was estimated that, in 1995, over 152 million men worldwide experienced ED. For 2025, the prevalence of ED is predicted to be approximately 322 million worldwide.
Men who do not respond or tolerate oral medications are best treated with an internal penile pump (IPP) commonly known as an inflatable implant. The Internal Penile Pump is an inflatable, water-filled device. During the course of a 45-minute outpatient procedure, the pump is inserted through a one-inch opening in the scrotal sac. By squeezing the pump, (which is contained completely within the scrotum), for approximately a minute, fluid is pumped into the penis, resulting in a long lasting erection. To return the penis to its flaccid state, simply press and hold down the pump. Once inserted, there is no maintenance required for the pump, which can remain in place for a lifetime. Couples are once again able to have spontaneous sex. Normal sensation including orgasm and ejaculation are not affected.
Penile injection therapy, intracavernous injection, involves the injection of a vasodilator (a chemical that relaxes arteries to increase blood flow) into the penis. Penile injected therapy is recognized as the most effective nonsurgical treatment for erectile dysfunction. However, due to the invasive nature, it is often used in men who have failed or have contraindications to other treatments such as oral therapies.
Exercise and lifestyle modifications may improve erectile function. Weight loss may help by decreasing inflammation, increasing testosterone, and improving self-esteem. Patients should be educated to increase activity, reduce weight, and stop smoking, as these efforts can improve or restore erectile function in men without comorbidities. Precise glycemic control in diabetic patients and pharmacologic treatment of hypertension may be important in preventing or reducing sexual dysfunction. 
Centrally active compounds such as apomorphine have been used in men with ED whose cardiovascular comorbidity may prohibit PDE5i use, or in men who have concurrent apomorphine use for its anti-parkinsonian properties. Unfortunately, its side effect profile and poor effectiveness compared to other ED treatments have impaired its mainstream utilization (118). It is suspected that the side effects of apomorphine relate to its D2 receptor affinity. D4 receptor agonists, such as ABT-724 and azulenylmethylpiperazines, may not have the same associated side effects and show potent pro-erectile effects in animal models compared to apomorphine (32,119).
Zerman et al. performed penile implant surgery in 245 men with neurolgic impairment caused by spinal cord injury, CNS neoplasm, CNS infection, MS and SB (110). Mean follow-up time of 7.2 years was achieved in 195 patients, 50 patients were excluded for lost to follow-up or death from nonurological causes. Interestingly, 135 patients underwent penile implantation to assist with management of urinary incontinence and improve ability for condom/intermittent catheterization. Ninety-two patients patient underwent implantation for ED. Eighty two percent of patients were satisfied with implantation for ED, and 67% of partners were satisfied. Complications included infection (5%), perforation (0–18%), and technical dysfunction (7–33%). Perforation rates were high with the malleable device when it was placed through a subcoronal incision. After adopting an infrapubic approach the perforation rates dropped substantially.
Another tip is to make sure you communicate with your partner what you like during the process of sex. Many men are not communicative about what really turns them on. If you are not aroused by what is going on, then you might experience ED. Make sure you tell your partner what turns you on. Communicating about intimacy should also lead to feeling more connected with your partner aiding in relaxing when you are sexual together.
Alprostadil self-injection. With this method, you use a fine needle to inject alprostadil (Caverject Impulse, Edex) into the base or side of your penis. In some cases, medications generally used for other conditions are used for penile injections on their own or in combination. Examples include papaverine, alprostadil and phentolamine. Often these combination medications are known as bimix (if two medications are included) or trimix (if three are included).
Parasympathetic pathways originate from the intermediolateral cell columns of the 2nd, 3rd and 4th sacral spinal cord segments. Preganglionic fibers pass through the pelvic plexus where they coalesce with sympathetic fibers from the superior hypogastric plexus. The cavernous nerves that innervate the penis arise from the portion of the pelvic plexus. The pelvic plexus also contains nerves that innervate the rectum, bladder and urinary sphincter and the nerve projections can be damaged during radical excision of the bladder, prostate and rectum, leading to iatrogenic ED (4).
Conditions associated with reduced nerve and endothelium function (eg, aging, hypertension, smoking, hypercholesterolemia, and diabetes) alter the balance between contraction and relaxation factors (see Pathophysiology). These conditions cause circulatory and structural changes in penile tissues, resulting in arterial insufficiency and defective smooth muscle relaxation. In some patients, sexual dysfunction may be the presenting symptom of these disorders.
In fact, one common reason many younger men visit their doctor is to get erectile dysfunction medication. Often, men with erectile dysfunction suffer with diabetes or heart disease, or may be sedentary or obese, but they don’t realize the impact of these health conditions on sexual function. Along with erectile dysfunction treatment, the doctor may recommend managing the illness, being more physically active, or losing weight.
ED usually has a multifactorial etiology. Organic, physiologic, endocrine, and psychogenic factors are involved in the ability to obtain and maintain erections. In general, ED is divided into 2 broad categories, organic and psychogenic. Although most ED was once attributed to psychological factors, pure psychogenic ED is in fact uncommon; however, many men with organic etiologies may also have an associated psychogenic component.
Choosing the treatment that is best for you comes down to preference and efficacy. Montague cites a study that surveyed three groups of men, all of whom were successfully using an ED treatment. One group was on oral medications, one was using injections and a third had surgically implanted pumps. The most satisfied users were those with the implanted prostheses.
Cavallini, G., Modenini, F., Vitali, G., & Koverech, A. (2005, November). Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomy. Urology, 66(5), 1080-5. Retrieved from http://www.sciencedirect.com/science/article/pii/S0090429505006515
The role of the endothelium in ED has been noted for a number of years and the overlapping of ED and other conditions, especially coronary heart disease, CVD, affecting endothelial function/dysfunction, is clearly present. The endothelial cell is now known to affect vascular tone and impact the process of atherosclerosis, and impacting ED, CVD and peripheral vascular disease.16
A vacuum constriction device (left) is a cylinder that is placed over the penis. The air is pumped out of the cylinder, which draws blood into the penis and causes an erection. The erection is maintained by slipping a band off of the base of the cylinder and onto the base of the penis. The band can stay in place for up to 30 minutes. The vacuum device can be safely used to treat most causes of erectile failure. Lack of spontaneity, discomfort, and cumbersomeness of the device seem to be the biggest concerns of patients.
Capogrosso, P., Colicchia, M., Ventimiglia, E., Castagna, G., Clementi, M. C., Suardi, N., ... Salonia, A. (2013, July). One patient out of four with newly diagnosed erectile dysfunction is a young man — worrisome picture from the everyday clinical practice. The journal of sexual medicine. 10(7), 1833–1841. Retrieved from https://onlinelibrary.wiley.com/doi/full/10.1111/jsm.12179
Supplements are popular and often cheaper than prescription drugs for ED. However, supplements have not been tested to see how well they work or if they are a safe treatment for ED. Patients should know that many over-the-counter drugs have been found on drug testing to have ‘bootlegged' PDE 5 Inhibitors as their main ingredient. The amounts of Viagra, Cialis, Levitra or Stendra that may be in these supplements is not under quality control and may differ from pill to pill. The FDA has issued consumer warnings and alerts.