Unfortunately, some patients may have an overly simplified understanding of the role of PDE5 inhibitors in ED management. Such patients may not expect or be willing to undergo a long evaluation and testing process to obtain a better understanding of their sexual problem, and they may be less likely to involve their partner in discussing their sexual relationship with the physician. They may expect to obtain medications through a phone call to their doctor or even over the Internet, with minimal or no physician contact at all.
Impotence is a common problem among men and is characterized by the consistent inability to sustain an erection sufficient for sexual intercourse or the inability to achieve ejaculation, or both. Erectile dysfunction can vary. It can involve a total inability to achieve an erection or ejaculation, an inconsistent ability to do so, or a tendency to sustain only very brief erections.
The prostaglandin E1 is contained in a small suppository located at the tip of an applicator. You should urinate first as this lubricates the urethra and makes it easier to insert the applicator into the tip of the urethra (urethral meatus, the opening at the tip of the penis that urine passes through). A patient can release the suppository into urethra by gently wiggling the applicator and pressing the button at the end. Rubbing the penis allows the suppository to dissolve, and the prostaglandin is absorbed through the tissue of the urethra into the penis. It takes 15 to 30 minutes for this occur. Once into the penis, the prostaglandin causes increased blood flow into the penis. The prostaglandin can be present in the ejaculate, and thus doctors recommend that men use a condom when having intercourse with a pregnant partner. Men may need to use a condom if vaginal irritation occurs in female partner.
A common and important cause of ED is vasculogenic. Many men with ED have comorbid conditions such as hyperlipidemia, hypercholesterolemia, tobacco abuse, diabetes mellitus, or coronary artery disease (CAD).  The Princeton III Consensus recommends screening men who present with ED for cardiovascular risk factors; ED may be the earliest presentation of atherosclerosis and vascular disease. 
Finally, gene therapy and stem cell research has widened the frontier of ED treatment proposed as possibility to even reverse ED. Specifically, gene therapy pertains to repairing the cause of ED by restoring defective gene function and/or altering the expression of the mutant gene (32). Most of the available data on gene therapy are in the animal model. However, a phase I clinical trial in men with ED undergoing intracavernous injection with a DNA plasmid carrying the alpha-subunit of the corporal smooth muscle Maxi-K channel showed promise in increased erectile function based on IIEF assessment sustained throughout the 3-month study period (122).
Sildenafil has been previously suggested as a treatment option for ED in men with epilepsy (77,78). However, Matos et al. warned that PDE5i are potentially pro-convulsant and should be used with great caution in men with epilepsy (79). Animal studies in rat and mice overwhelmingly suggest PDE5i can reduce seizure threshold. In human trials, seizures were rare but reported. PDE5i exerted their proconvulsive effect by lower seizure threshold possibly by worsening sleep or obstructive sleep apnea, causing cardiovascular changes, or leading to EEG changes specifically with tadalafil use.
Poor sleep patterns can be a contributing factor for erectile dysfunction, Mucher says. One review published in the journal Brain Research emphasized the intricate relationship between the level of sex hormones like testosterone, sexual function, and sleep, noting that testosterone levels increase with improved sleep, and lower levels are associated with sexual dysfunction. Hormone secretion is controlled by the body’s internal clock, and sleep patterns likely help the body determine when to release certain hormones.
ED can also occur among younger men. A 2013 study found that one in four men seeking their first treatment for ED were under the age of 40. The researchers found a stronger correlation between smoking and illicit drug use and ED in men under 40 than among older men. That suggests that lifestyle choices may be a main contributing factor for ED in younger men.
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.
Infection is a concern after placement of a penile prosthesis and is reported as a complication in up to 20% of men undergoing placement of a penile prosthesis. If the device becomes infected more commonly, it needs to be removed. Another prosthesis can be placed after the infection is treated and the penile tissues have healed, but it is a difficult surgery. Erosion of the prosthesis, whereby it compresses through the corporal tissue, into the urethra may occur. Symptoms include pain, blood in the urine, discharge, abnormal stream, and malfunction of the prosthesis. If the prosthesis erodes, it will need to be removed. A catheter is placed to allow the urethra to heal.
The pathogenesis of organic ED is related to dysfunction of the endothelium. Endothelial cells can become injured through a variety of mechanisms, most of which cause oxidative stress on the tissues. Many of these causes of oxidative stress are related to lifestyle issues which lead to hypertension, diabetes and dyslipidaemia (figure 1). Endothelial cell dysfunction results in reduction of endothelium-dependent vasorelaxation as well as increased adhesion of leukocytes to the endothelium. Endothelial cell injury then leads to a variety of sequelae, including ED, other types of vasoconstriction, atherosclerosis and thrombus formation.18
Conditions that may be associated with ED include diabetes, [25, 26, 27] hypertension,  , and CAD, as well as neurologic disorders, endocrinopathies, benign prostatic hyperplasia,  , sleep apnea  , COPD,  and depression (see Table 1 below). [32, 33, 34, 35] In fact, almost any disease may affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the corpora cavernosa or influence the patient’s psychological mood and behavior.
Fortunately, impotence is usually treatable. A thorough evaluation starting with a history and physical exam is needed to help diagnose the underlying cause. Once the cause of impotence is determined, treatment can be tailored to target that cause and any other contributing factors. Treatments used for impotence may include medications, vacuum devices, surgery, and psychotherapy.
Among the phenomena in the ageing man are a decrease in erectile function and testosterone levels. Add to these, increased risk for CVD, muscle wasting, decrease in bone density and libido, with all of these factors having an interplay with testosterone metabolism.33 Androgens play a key role in maintaining erectile function through four main mechanisms. Androgen deprivation has been shown to result in impairment of NO synthase release, altered PDE5 expression and activity, impaired cavernosal nerve function, and contribution to veno-occlusive disease in the penis.34 The role of testosterone replacement therapy (TRT) as a potential to improve erectile function in the man with ED remains an issue for patient and physicians who are comfortable treating androgen deficiency which include primary care physicians and specialists. Androgens are known to have a significant impact on the function of the smooth musculature within the corpus spongiosum.35
3. Are there physical causes of erectile dysfunction? Erectile dysfunction may be a symptom of underlying medical conditions, which if not detected may cause further medical problems. A prior history of cigarette smoking, heart attacks, strokes, and poor circulation in the extremities (for example, intermittent claudication or cramping in your leg[s] when you walk) suggest atherosclerosis as the cause of the erectile dysfunction. Loss of sexual desire and drive, lack of sexual fantasies, gynecomastia (enlargement of breasts), and diminished facial hair suggest low testosterone levels. A prior history of pelvic surgery or radiation and trauma to the penis/pelvis/perineum can cause problems with the nerves and blood vessels. Symptoms of intermittent claudication of the lower extremities with exercise may suggest a vascular problem as a cause of the erectile dysfunction.
Our physicians can help you treat E.D. with prescription medication. We will recommend a personalized dosage for Viagra, Sildenafil (the same medication as in Viagra), Cialis, or Tadalafil (the same medication in Cialis). You will receive a treatment plan designed by Dr. Seth Cohen, Head of Men’s Health, NYU Division of Sexual Medicine and Reconstruction and Dr. Steven Lamm, Director of NYU Men’s Health Center. During your online visit, you can tell your doctor if you have a medication preference. Learn more about E.D. treatment
In order to establish whether normal erections are occurring overnight (nocturnal erections), the doctor may organise nocturnal penile tumescence (NPT) testing. This involves wearing a monitor overnight in your own home. The data from this monitor is then assessed to analyse how often erections occurred, how long they lasted, and how rigid and large the penis was during the erections. If NPT testing is normal, the cause of erectile dysfunction is usually psychological. If not, further testing of the blood flow in the genital area may be required to see if there is blockage or leakage. The doctor may also organise a blood test of levels of hormones such as testosterone, prolactin and thyroid stimulating hormone to see if these are contributing to the erectile dysfunction.