Erections also require neural input to redirect blood flow into the corpora cavernosae. Psychogenic erections secondary to sexual images or auditory stimuli relay sensual input to the spinal cord at T-11 to L-2. Neural impulses flow to the pelvic vascular bed, redirecting blood flow into the corpora cavernosae. Reflex erections secondary to tactile stimulus to the penis or genital area activate a reflex arc with sacral roots at S2 to S4. Nocturnal erections occur during rapid-eye-movement (REM) sleep and occur 3–4 times nightly. Depressed men rarely experience REM sleep and therefore do not have nocturnal or early-morning erections.

PDE 5 inhibitors are broken down primarily by enzyme, cytochrome P450enzyme CYP3A4. Medications that decrease or increase the activity of CYP3A4 may affect levels and effectiveness of PDE 5 inhibitors. Such drugs include medications for the treatment of HIV (protease inhibitors) and the antifungal medications ketoconazole and itraconazole. Thus caution is recommended.
We can partially speak to this issue by looking at data from the first wave of the National Survey of Sexual Health and Behavior (NSSHB), a nationally representative US sex survey conducted in 2009 with thousands of Americans aged 14-94 [3]. As part of this study, male participants were asked whether they’d experienced any erectile difficulties the last time they had sex via a single item with five response options, ranging from “not difficult” to “very difficult.” Obviously, this is a quite different question compared to the other studies because it only focused on a single event (the most recent one in memory) and it was more complex than a simple yes/no answer. The researchers also divided men into slightly different age groups.

Although ED and diabetes are two separate conditions, they tend to go hand in hand. Half of men with diabetes will experience ED within 10 years of their diagnosis.8 For some men, ED may be the first symptom of diabetes even if they have not yet been diagnosed, particularly in men younger than 45.6 Left untreated, ED can damage self-confidence and relationships.

Normal male sexual function requires a complex interaction of vascular, neurological, hormonal, and psychological systems. The initial obligatory event is acquisition and maintenance of an erect penis, which is a vascular phenomenon. Normal erections require blood flow into the corpora cavernosae and corpus spongiosum. As the blood accelerates, the pressure within the intracavernosal space increases dramatically to choke off penile venous outflow. This combination of increased intracavernosal blood flow and reduced venous outflow allows a man to acquire and maintain a firm erection.
The most common inflatable prosthesis is the three-piece penile prosthesis. It is composed of paired cylinders, which doctors surgically insert inside the penis. Patients can expand the cylinders using pressurized fluid (see figure 3). Tubes connect the cylinders to a fluid reservoir and pump, which doctors also surgically implant. The reservoir is usually in the pelvis. A doctor places the pump in the scrotum. By pressing on the pump, sterile fluid transfers from the reservoir into the cylinders in the penis. An erection is produced primarily by expansion of the width of the penis, however, one model can increase in length a small amount also. Lock-out valves in the tubing prevent the fluid from leaving the cylinder until a release valve is pressed. By pressing the relief valve and gently squeezing the penis, the fluid within the cylinders transfers back into the reservoir.
Though it's most common among older men, it's possible for young men to get erectile dysfunction. When young men develop ED, it's usually a result of psychological problems such as anxiety, stress, depression or relationship problems. However, physical problems such as diabetes, nerve problems, injury or other medical conditions may also lead to erectile dysfunction in younger men. If you're having frequent or ongoing trouble getting or keeping an erection long enough to have sex, talk to your doctor.
For obvious reasons, ED can be a sensitive subject, one that until relatively recently men were more likely to try to hide than to deal with. Fortunately, a deeper understanding of the variety of causes of erectile dysfunction has led to medications, therapies, and other treatments that can be more individualized and more likely to be effective—and more open discussion about addressing the concern.
Yet another common erectile dysfunction treatment that can be used in combination with oral drugs is a vacuum pump. This device consists of a plastic cylinder, a pump, a set of constriction bands, and a water-soluble lubricant. The lubricant is applied to the base of the penis to help form an airtight seal. The cylinder is placed over the flaccid penis and held tight against the pelvis. The pump is used to create a vacuum within the cylinder, drawing blood into the penis. Once the penis is engorged with blood, a constriction band is rolled off the cylinder to near the base of the penis. The constriction band is helpful for men with venous leakage, in which blood flows out of the penis as fast as it flows in. However, it should be left on for no more than 30 minutes at a time.
Medications: Many common medicines produce erectile dysfunction as a side effect. Medicines that can cause erectile dysfunction include many used to treat high blood pressure, antihistamines, antidepressants, tranquilizers, and appetite suppressants. Examples of common medicines that can cause erectile dysfunction include propranolol (Inderal) or other beta-blockers, hydrochlorothiazide, digoxin (Lanoxin), amitriptyline (Elavil), famotidine (Pepcid), cimetidine (Tagamet), metoclopramide (Reglan), naproxen, indomethacin (Indocin), lithium (Eskalith, Lithobid), verapamil (Calan, Verelan, Isoptin), phenytoin (Dilantin), gemfibrozil (Lopid), amphetamine/dextroamphetamine (Adderall), and phentermine. Prostate cancer medications that lower testosterone levels such as leuprolide (Lupron) may affect erectile function. Some chemotherapies such as cyclophosphamide (Cytoxan) may affect erectile function.
“Although having sex at 70 is not the same as having sex at 20, erectile dysfunction is not a normal part of aging,” according to Michael Feloney, MD, urologic surgeon and expert on sexual dysfunction issues at the Nebraska Medical Center in Omaha. “You should still be able to have a satisfying sex life as you age." If you are experiencing erectile dysfunction, these 10 dos and don'ts may help.
Many men who suffer from erectile dysfunction feel guilty about being unable to please their partner. If the problem persists, the guilt becomes more than just a side effect – it can contribute to the ongoing cycle of ED as well. Guilt is often paired with low self-esteem, and not just in men with erectile dysfunction. Guilt and shame are feelings that are commonly linked to mental health issues such as depression. In fact, feelings of worthlessness and inappropriate guilt is one of the clinical criteria for major depressive disorder, according to the DSM-5.
Multiple authors have demonstrated that anxiety, depression, and stress clearly produce major neurochemical and neuroendocrine changes in the brain (10,11). Changes in neurobiology would be expected to contribute to impaired erectile function. Stress and anxiety lead to increased epinephrine production, and heightened sympathetic tone leads to exaggerated cavernosal smooth muscle contraction, inability of smooth muscle to relax, and subsequent erectile dysfunction (6,7). Failure to achieve a fully rigid erection may aggravate performance anxiety leading to a vicious cycle.

Relationship problems often complicate erectile dysfunction. Improving your relationship may be part of the solution. It may be a good idea to get counseling together from a sex therapist, marriage counselor, or a medical specialist. "I almost always see couples together to discuss erectile dysfunction. It often turns out that both partners have issues regarding the sexual relationship and once they are out in the open, couples can work together on a more satisfying sexual experience," says Feloney.
Treatments include psychotherapy, adopting a healthy lifestyle, oral phosphodiesterase type V (PDE5) inhibitors (Viagra, Levitra, Cialis, Stendra, and Staxyn), intraurethral prostaglandin E1 (MUSE), intracavernosal injections (prostaglandin E1 [Caverject, Edex], Bimix and Trimix), vacuum devices, penile prosthesis and vascular surgery, and (in some cases) changes in medications when appropriate.
Other hormone levels: Measurement of other hormones beside testosterone (luteinizing hormone [LH], prolactin level, and cortisol level) may provide clues to other underlying causes of testosterone deficiency and erectile problems, such as pituitary disease or adrenal gland abnormalities. Doctors may check thyroid levels in some individuals as both hypothyroidism (low thyroid function) and hyperthyroidism (overactive thyroid function) can contribute to erectile dysfunction.
ED has been for long time considered a problem mainly related to psychological conditions and distress. Accordingly, until phosphodiesterase type 5 inhibitors (PDE5i) were introduced, psychoanalysis and cognitive-behavioural therapy were the only option for ED. In the last few decades, ED has been recognized as a clinical consequence of several different organic diseases and the importance of vascular health in erectile function has been so emphasized that ED is now considered not only the result of vascular impairment, but also a harbinger of forthcoming cardiovascular (CV) events (17). Despite the increasing attention of research towards organic mechanisms and conditions leading to ED, it is now known that considering this symptom as entirely due to organic disorders, is as imprecise as considering it only secondary to psychological conditions. In fact, this pathogenetic dichotomy is now obsolete (1,18,19), because it is now known that ED is a multidimensional disorder deriving from the interaction of different components related to organic conditions, relational context and psychological status (20,21). Even when only one of these components is involved in the initial development of erectile impairment, eventually the other ones will appear, thus further worsening ED (21-23). The multidimensional nature of ED is still not fully accepted by health care professionals when dealing with young patients. In fact, complaints of ED in young men is often underestimated and attributed to transient and self-limiting psychological conditions, such as performance anxiety. Young patients are often reassured without any further medical investigations, including physical exam. However, organic disorders, as well as relational and psychological or psychiatric conditions, can be meaningful in determining ED in younger men. In a population of subjects seeking medical care at the Sexual Medicine and Andrology Unit of the University of Florence for sexual dysfunction, the first tertile of age (n=1,873 subjects) represents younger subjects (18–44 years). Pathogenetic components of ED in our sample are investigated by the Structured Interview on Erectile Dysfunction (SIEDY), a structured interview including 13 questions, whose answers, organized in a Likert scale, provide three scales, one for the organic subdomain [(SIEDY Scale 1); (22)], one for the relational subdomain [(SIEDY Scale 2); (23)] and one for the intrapsychic subdomain [(SIEDY Scale 3); (21)]. According to these scale scores, organic, relational and intrapsychic conditions are all significant risk factors for ED in younger patients of our population (Figure 2).
To understand what happens in ED, it's helpful to know some anatomical basics. When aroused by either sensory or mental stimuli, the brain sends a signal through the nerves to the penis, causing the muscles there to relax. This opens up space for blood to flow in and engorge the penis. A membrane within the penis traps blood inside to help maintain the erection, which subsides when the penile muscles contract, forcing blood back into the rest of the body. Any number of things can go wrong in this process, leading to erectile dysfunction.
It's tempting to think of erectile dysfunction (ED) as a condition that only affects aging men. But a small number of younger men will develop erectile dysfunction too. One survey found that about 2 percent of men in their 20s are unable to have erections. Overall, 6.5 percent of these younger males said they had at least occasional difficulty getting or sustaining an erection.

Total testosterone levels: Health care professionals should obtain a patient's blood samples for total testosterone levels in the early morning (before 8 a.m.) because the testosterone levels go up and down throughout the day. If you have a low testosterone level, a health care professional should check it again to confirm that it is truly low. In some men, a specialized test measuring the active form of testosterone (free or bioavailable testosterone) may be recommended.


Vacuum devices for ED, also called pumps, offer an alternative to medication. The penis is placed inside a cylinder. A pump draws air out of the cylinder, creating a partial vacuum around the penis. This causes it to fill with blood, leading to an erection. An elastic band worn around the base of the penis maintains the erection during intercourse.


Nerve or spinal cord damage: Damage to the spinal cord and nerves in the pelvis can cause erectile dysfunction. Nerve damage can be due to disease, trauma, or surgical procedures. Examples include injury to the spinal cord from automobile accidents, injury to the pelvic nerves from prostate surgery for cancer (prostatectomy), and some surgeries for colorectal cancer, radiation to the prostate, surgery for benign prostatic enlargement, multiple sclerosis (a neurological disease with the potential to cause widespread damage to nerves), and long-term diabetes mellitus.

Patients should continue testosterone therapy only if there is improvement in the symptoms of hypogonadism and should be monitored regularly. You will need periodic blood tests for testosterone levels and blood tests to monitor your blood count and PSA. Testosterone therapy has health risks, and thus doctors should closely monitor its use. Testosterone therapy can worsen sleep apnea and congestive heart failure.

Penile Injection Medication: This is just what it sounds like. Injected at home directly into the penis, the medication alprostadil produces erection by relaxing certain muscles, increasing blood flow into the penis and restricting outflow. Although some sources report an 80 percent success rate, the therapy has disadvantages, such as risks of infection, pain, and scarring—fibrosis—in the penis, and it may also cause priapism. A popular version of this medication is Upjohn Corporation’s Caverject. The MUSE System, by VIVUS, involves the same medicine (a pellet of alprostadil) applied with an eye-dropper-like applicator, directly into the urethra.
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