Alprostadil is a potent vasodilator and smooth muscle relaxant identical to the naturally occurring PGE1. PGE1 binds with specific receptors on smooth muscle cells and activates intracellular adenylate cyclase to produce cAMP, which in turn induces tissue relaxation through a second messenger system (96). PGE1 is the only FDA approved form of intracavernosal therapy and is available commercailly as EDEX, or Caverject. Its efficacy was demonstrated in several clinical trials where the rate of responders ranged from 40% to 80% (97,98). The most common adverse event is penile pain, which is not related to the injection of the medication itself. In men with prolonged use the pain is usually self-limited (99).
Is your erectile dysfunction due to psychological (stress, relationship problems, etc.) or physical factors? Your doctor may ask if you note erections at night or in the early morning. Men have involuntary erections in the early morning and during REM sleep (a stage in the sleep cycle with rapid eye movements). Men with psychogenic erectile dysfunction (erectile dysfunction due to psychological factors such as stress and anxiety rather than physical factors) usually maintain these involuntary erections. Men with physical causes of erectile dysfunction (for example, atherosclerosis, smoking, and diabetes) usually do not have these involuntary erections. Men with psychogenic erectile dysfunction may relate the onset of problems to a "stressor," such as failed relationship. Your doctor may suggest a test to determine if you have erections during sleep, which may suggest that there may be a psychological cause of the erectile dysfunction.
All NOS subtypes produce NO, but each may play a different biologic role in various tissues. nNOS and eNOS are considered constitutive forms because they share biochemical features: They are calcium-dependent, they require calmodulin and reduced nicotinamide adenine dinucleotide phosphate for catalytic activity, and they are competitively inhibited by arginine derivatives. nNOS is involved in the regulation of neurotransmission, and eNOS is involved in the regulation of blood flow.
Aging, liver and kidney problems, and concurrent use of certain medications (such as erythromycin [an antibiotic] and protease inhibitors for HIV) slows the metabolism (breakdown) of sildenafil. Slowed breakdown allows sildenafil to accumulate in the body and potentially may increase the risk of side effects. Therefore, in men over 65 years of age, in men with significant kidney and liver disease, and in men who also are taking medications called protease inhibitors, the doctor will initiate sildenafil at a lower dose (25 mg) to avoid accumulation of sildenafil in the body. A protease inhibitor ritonavir (Norvir) is especially potent in increasing the accumulation of sildenafil, thus men who are taking Norvir should not take sildenafil doses higher than 25 mg and at a frequency of no greater than once in 48 hours. Other medications that may affect the level of sildenafil include erythromycin and ketoconazole.
Erectile dysfunction (ED) related to compromise of the nervous system is an increasingly common occurrence. This may be due to the multifactorial nature of ED, the myriad of disorders affecting the neurotransmission of erectogenic signals, and improved awareness and diagnosis of ED. Nevertheless, neurogenic ED remains poorly understood and characterized. Disease related factors such as depression, decreased physical and mental function, the burden of chronic illness, and loss of independence may preclude sexual intimacy and lead to ED as well. The amount of data regarding treatment options in subpopulations of differing neurologic disorders remains scarce except for men with spinal cord injury. The treatment options including phosphodiesterase inhibitors, intracavernosal or intraurethral vasoactive agents, vacuum erection devices (VED) and penile prosthetic implantation remain constant. This review discusses the options in specific neurologic conditions, and briefly provides insight into new and future developments that may reshape the management of neurogenic ED.
The art of acupuncture has become the new treatment for everything from back pain, depression, and even ED. Impotence could be more of a state of mind, and acupuncture may help. Through this alternative therapy, fine needles are placed in various parts of the body to relieve pain or stress. Although there are many mixed studies for acupuncture and ED, many tend to confirm positive results. A 1999 study found acupuncture improved the quality of erection and even restored sexual activity in 39 percent of participants.
A number of treatments are available to treat erectile dysfunction. The typical treatment strategy starts with simple to use, noninvasive therapies and progresses to more invasive surgical therapies as needed. In all men, the first step is determining if there are any modifiable risks factors that can either improve or prevent progression of erectile dysfunction. Since the risk of developing ED is increased in the presence of diabetes, heart disease, and hypertension, it is thought that better control/prevention of these conditions may have a benefit in ED. Similarly, it is thought that lifestyle modifications to improve vascular function such as avoiding smoking, maintaining ideal body weight, and engaging in regular exercise might either prevent or reverse ED. Sexual counseling may also be useful in addressing relationship stressors as you work on improving your erectile function.
Does drinking water improve erectile dysfunction? Erectile dysfunction or ED is a common concern for men. Everyday factors, such as hydration levels, may affect a person's ability to get or maintain an erection. Drinking water may, therefore, help some men with ED. In this article, learn about the link between hydration and ED, and other factors that can cause ED. Read now
If conservative treatments for erectile dysfunction are not successful your consultant may recommend penile prosthetic surgery. A penile prosthetic is an implant that allows men with erectile dysfunction to have an erection. Prosthetics may also be used for patients with Peyronie’s disease. There are several types of penile implants. Your consultant will assess your own situation and recommend the implant that meets your needs.
Risks associated with injection therapy including bleeding, pain with injection, penile pain, priapism, and corporal fibrosis (scarring inside of the corpora cavernosa). There is also concern that repetitive injections in the same area could cause scar tissue to build up in the tunica albuginea that could create penile curvature. Thus, doctors recommended that one alternate sides with injection and perform injections no more frequent than every other day.
The dorsal artery provides for engorgement of the glans during erection, whereas the bulbourethral artery supplies the bulb and the corpus spongiosum. The cavernous artery effects tumescence of the corpus cavernosum and thus is principally responsible for erection. The cavernous artery gives off many helicine arteries, which supply the trabecular erectile tissue and the sinusoids. These helicine arteries are contracted and tortuous in the flaccid state and become dilated and straight during erection. 
The other 5 percent of prostheses are either pump devices in which the saline is permanently in the prosthesis, not in a separate reservoir (urologists may recommend this for men who have had multiple surgeries); or a pair of semi-rigid, malleable rods implanted in the penis, which render it hard at all times. The patient manually shifts the penis into an erect position for sex.
One of the first steps is to distinguish between physiological and psychological ED. Determining whether involuntary erections are present is important in eliminating the possibility of psychogenic causes for ED. Obtaining full erections occasionally, such as nocturnal penile tumescence when asleep (that is, when the mind and psychological issues, if any, are less present), tends to suggest that the physical structures are functionally working. Similarly, performance with manual stimulation, as well as any performance anxiety or acute situational ED, may indicate a psychogenic component to ED.
The common PDE5 inhibitor drugs approved in the United States are sildenafil (Viagra), vardenafil (Levitra and Staxyn, the generic form), tadalafil (Cialis), or avanafil (Stendra). All of the currently approved PDE5 inhibitors work in the same way. They differ in the number of available doses, how quickly they work and last in your system, the dosing, and to some extent in the side effects. However, they generally share the same indications and contraindications. Currently, tadalafil is the only medication that patients can take on a daily basis and is approved for the treatment of both ED and BPH (benign enlargement of the prostate).
However, in contrast, a recent systematic review of published studies, the authors concluded that overall, the addition of testosterone to PDE-5 inhibitors might benefit patients with ED associated with testosterone levels of less than 300 ng/dL (10.4 nmol/L) who failed monotherapy.  A limitation of existing studies are their heterogeneous nature and methodological drawbacks.
It is important for clinicians prescribing these drugs to make the patient aware of the action of the drugs especially the fact that they do not result in an immediate erection, and that they do not cause an erection without sexual stimulation. There is frequently a great expectation when men begin using these drugs and it is wise to temper their enthusiasm and explain they do not work immediately, and may not work every time, but also let the patient know that if these drugs do not work, there are other options.
Research has even found possible links to frequent ejaculation and a lower risk of prostate cancer. In one study of 32,000 men published in 2016 in the journal European Urology, for example, men who ejaculated at least 21 times per month while in their 20s were less likely to be diagnosed with prostate cancer than those who ejaculated four to seven times per month. And men who ejaculated more often in their 40s were 22 percent less likely to get a prostate cancer diagnosis.
MUSE should not be used in men with a history of urethral stricture (narrowing of the tube in the penis that urine and semen pass through), inflammation or infection of the glans (tip) of the penis (balanitis), severe hypospadias (a condition where the opening of the urethra is not at the tip of the penis, rather on the underside of the penis), penile curvature (abnormal bend to the penis), and urethritis (inflammation/infection of the urethra).
Dr Kenny du Toit is a urologist practicing in Rondebosch, Cape Town. He is also consultant at Tygerberg hospital, where he is a senior lecturer at Stellenbosch University. He is a member of the South African Urological Association, Colleges of Medicine South Africa and Société Internationale d’Urologie. Board registered with both the HPCSA (Health professions council of South Africa) and GMC (General medical council UK). He has a keen interest in oncology, kidney stones and erectile dysfunction.http://www.dutoiturology.co.za
The mechanisms by which testosterone plays a role in erectile function are not completely understood. A study evaluating the effect of testosterone on erections in surgically castrated rabbits and control animals, in which the rabbits’ intracavernosal pressures were compared after cavernosal nerve stimulation, determined that castrated rabbits had much lower pressures after stimulation than control rabbits did.  Notably, the pressures increased when castrated rabbits received exogenous testosterone replacement.
Sexual stimulation causes the release of neurotransmitters from cavernosal nerve endings and relaxation factors from endothelial cells lining the sinusoids. NOS produces NO from L-arginine, and this, in turn, produces other muscle-relaxing chemicals, such as cGMP and cyclic adenosine monophosphate (cAMP), which work via calcium channel and protein kinase mechanisms (see the image below). This results in the relaxation of smooth muscle in the arteries and arterioles that supply the erectile tissue, producing a dramatic increase in penile blood flow.
"Medications that create blood flow to the penis can't help when an erection is blocked by the fear or anxiety of the fight-or-flight response,” says Feloney. “This type of erectile dysfunction probably has a lot to do with evolution — men didn't need an erection when a dinosaur was chasing them." The best way to treat erectile dysfunction caused by performance anxiety, depression, a poor relationship, or stress may be with a combination of ED drug treatment and sex therapy, individual therapy, or couples therapy from sexual health professionals.
The vacuum device creates a vacuum to pull blood into the penis. Unlike a normal erection, the inflow of blood does not continue once the individual removes the vacuum device. The rubber band placed at the base of the penis constricts the penis to prevent the blood from leaving the penis. As there is no inflow or outflow of blood when the rubber band is in place, it is uncommon for the tip of the penis (the glans) to appear a little blue and the penis to be cooler. Once intercourse is completed, the individual removes the rubber band and the blood drains out of the penis.
You can also consider using a cock ring or penis ring if you are able to get an erection but have trouble maintaining it. Cock rings work by trapping the blood inside your penis so it remains harder for longer. You can purchase one in a sex store or online for about $5 and you put in on over your penis and testicles when you are half hard and keep it on until you are finished with sex. It’s a great cheap fix for erectile issues.
This penile tumescence monitor is placed at the base and near the corona of the penis. It is connected to a monitor that records a continuous graph depicting the force and duration of erections that occur during sleep. The monitor is strapped to the leg. The nocturnal penile tumescence test is conducted on several nights to obtain an accurate indication of erections that normally occur during the alpha phase of sleep.
With sex therapy, your counselor looks at the sexual problems you and your partner are having. Sex therapy works with problems such as performance anxiety, which means that you worry so much about whether you will be able to have sex that you are not able to. It also helps when you have erection problems that are not due to physical or drug problems, or premature ejaculation (you come too quickly). It may help you to reach orgasm or to learn to relax enough to avoid pain during sex. Counseling can help you to adjust to the treatment you and your doctor choose.
In 1983, Brindley injected the corpora of several SCI men with phentolamine (85). Two out of the three men had a sufficient erection produced. Since then multiple reports on the efficacy of intracavernosal therapy have been published using, phentolamine, papaverine, prostaglandin, vasoactive intestinal peptide (VIP), and these medications in combination (86-90). These medications have been found to be extremely effective for neurogenic ED due to their ability act locally and essentially bypassing neuronal pathways. Local therapies are usually considered second-line after PDE5i fail to elicit a desired response which can occur in about 25–30% of men with ED, in general (91). Furthermore, the locally delivered medications can be quite dangerous if not used appropriately as priapism and significant pain with injections can occur. These specific occurrences have been suggested as a reason for high discontinuation rates with intracavernosal therapy (92).
Prior to starting with treatment of erectile dysfunction, it is important to make sure that it is safe from a medical standpoint to participate in sexual activity. Sexual activity is physical exertion, and in some men with significant heart disease, this increase in physical exertion can increase the risk of a heart attack. Thus, it is very important to discuss your cardiovascular risks with your doctor prior to trying any medication or treatment for erectile dysfunction.
A vacuum erection device is a plastic tube that slips over the penis, making a seal with the skin of the body. A pump at the other end of the tube makes a low-pressure vacuum around the erectile tissue, which results in an erection. An elastic ring is then slipped onto the base of the penis. This holds the blood in the penis (and keeps it hard) for up to 30 minutes. With proper training, 75 out of 100 men can get a working erection using a vacuum erection device.