The PDE5 inhibitors sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis) are prescription drugs which are taken orally.[22]:20–21 Additionally, a cream combining alprostadil with the permeation enhancer DDAIP has been approved in Canada as a first line treatment for erectile dysfunction.[25] Penile injections, on the other hand, can involve one of the following medications: papaverine, phentolamine, and prostaglandin E1, also known as alprostadil.[22]:25
Treatment depends on the underlying cause. In general, exercise, particularly of the aerobic type, is effective for preventing ED during midlife. Exercise as a treatment is under investigation.[22]:6, 18–19 For tobacco smokers, cessation often results in a significant improvement.[23] Oral pharmacotherapy and vacuum erection devices are first-line treatments,[22]:20, 24 followed by injections of drugs into the penis, as well as penile implants.[22]:25–26 Vascular reconstructive surgeries are beneficial in certain groups.[24]

Several treatments were promoted in the pre-PGE1, pre-prostaglandin era, including yohimbine, trazodone, testosterone, and various herbal remedies. None of these is currently recommended under the updated American Urological Association Guidelines for the Treatment of Erectile Dysfunction.15 Testosterone supplementation is only recommended for men with low testosterone levels.
The Prostate Cancer Prevention Trial was a landmark study by Thompson et al that prospectively assessed the time to developing CVD after the diagnosis of ED. There were 4247 men with no ED at study entry; 2420 developed incident ED (defined as the first report of ED of any grade) over 5 years. Those men that developed ED had a 1.45-fold higher probability of experiencing a CV event compared with men who did not develop ED.27
Several pathways have been described to explain how information travels from the hypothalamus to the sacral autonomic centers. One pathway travels from the dorsomedial hypothalamus through the dorsal and central gray matter, descends to the locus ceruleus, and projects ventrally in the mesencephalic reticular formation. Input from the brain is conveyed through the dorsal spinal columns to the thoracolumbar and sacral autonomic nuclei.
Erectile dysfunction in younger men, unless they're diabetic or have suffered some unusually cruel injury, is generally caused by stress, rather than any physical condition. High levels of cortisol or adrenaline (both byproducts of stress) in the body stymie the supply of oxygen to the organs, thereby decreasing blood flow to the penis. And the penis without blood has as much chance of getting up as a balloon without air. Which is why I found it easier to have sex with people I wasn't emotionally invested in: Once the fear of rejection is removed, sex is no big deal.
Apomorphine is a non-selective D1/D2 receptor agonist with moderate efficacy and good tolerability in the treatment of mild ED (80). Apomorphine can be administered via subcutaneous injection or sublingually. However, studies have shows a lower efficacy for apomorphine compared to oral sildenafil (81,82). Apomorphine has a set role in the management of PD for non-motor symptoms, and has been reported to cause spontaneous erections and possible hypersexuality in PD men (83,84). Its role in the management of ED has been postulated for men with PD but should be considered as an alternative to sildenafil.
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).
Viagra is available in three strengths: 25 mg, 50 mg, and 100 mg. Viagra works best if taken on an empty stomach about 30-45 minutes before sexual activity. Optimal results may not be realized until the medication has been tried six to eight times. Viagra may be used cautiously with alpha-blocker medications as long as sufficient time has passed between their dosing.
Also called vacuum devices, penile pumps are devices that are placed over the penis to draw blood into the shaft. Once the vacuum creates an erection, the retaining band is slid down to the lower end of the penis and the pump is removed. An erection typically will last long enough for intercourse but your penis may be cold to the touch and the rubber band may restrict ejaculation.22
Recently, the US Food and Drug Administration (FDA) has issued a safety announcement regarding TRT. In part it reads ‘The benefit and safety of these medications have not been established. We are also requiring these manufacturers to add information to the labeling about a possible increased risk of heart attacks and strokes in patients taking testosterone.’37
In patients who either fail to respond to first or second-line therapy, or are not interested in the conservative therapies, penile prosthesis implantation is available. Malleable and rigid implants were available for many years, but in 1973 the world of penile prosthetics took a giant leap forward with the advent of the inflatable penile implant. Most implants done nowadays are of the inflatable variety. Adverse events including malfunction and infection are rare, and patient satisfaction is very high.45
Erectile dysfunction may be an unpleasant condition that no one really wants to talk about, failing to acknowledge it won’t make the problem go away. Your best defense against health problems like this is to learn everything you can about it so you can tackle the problem at the root. If you’re ready to stop living in embarrassment about your sexual function, become an advocate for yourself and your own health and talk to your doctor.
The development of an erection is a complex event involving integration of psychologic, neurologic, endocrine, vascular, and local anatomic systems. Positron emission tomography scanning studies have suggested that sexual arousal is activated in higher cortical centers that then stimulate the medial preoptic and paraventricular nuclei of the hypothalamus.5 These signals ultimately descend through a complex neural network involving the parasympathetic nervous system and eventually activate parasympathetic nerves in the sacral area (S2 to S4).
When lifestyle changes alone don’t work, drug therapy (Viagra®, Cialis®, Levitra®, etc.) is normally the next step. Most of these medications work similarly to enhance a natural chemical in your body that relaxes the muscles in your penis. The goal of this medication is to increase your response to sexual stimulation by increasing the blood flow in your penis allowing you to get an erection.22
The Latin term impotentia coeundi describes simple inability to insert the penis into the vagina; it is now mostly replaced by more precise terms, such as erectile dysfunction (ED). The study of ED within medicine is covered by andrology, a sub-field within urology. Research indicates that ED is common, and it is suggested that approximately 40% of males experience symptoms compatible with ED, at least occasionally.[38] The condition is also on occasion called phallic impotence.[39] Its antonym, or opposite condition, is priapism.[40][41]
Multiple combinations of intracavernosal therapy exist and the effectiveness of them varies based on patient characteristics and varying dosing strength (Table 1). Combination therapy have been extremely effective in the SCI population, and have several advantages including a reduction in cost per dose and side effects base on the lowered dose of each component (101,102). Effectiveness of combination therapy in the spinal cord population is well established, but no specific dose recommendations can be made based on the data (103-106). The use of combination therapy on other forms of neurogenic ED have not been well studied, but there use can be trialed as second-line therapy, or for populations were the side effects of PDE5i may preclude use such as in MSA due to hypotension.
The symptoms of erectile dysfunction include difficulty achieving an erection, trouble maintaining an erection, and a reduced interest in sex. Because male sexual arousal is a fairly complex process, it can sometimes be difficult to identify a specific cause. Arousal starts in the brain but it also involves the nerves, muscles, and blood vessels and can be impacted by hormones and emotions. If a problem develops with any of these things, erectile dysfunction could be the consequence.
"For men who are unwilling or unable to self-inject alprostadil, the FDA has approved this dissolvable pellet that can be inserted directly into the urethra, the opening of the penis," says Dr. Feloney. MUSE, with an inspiring name that actually stands for medicated urethral system for erection, will trigger an erection in about 10 minutes that may last as long as an hour. Using MUSE to treat ED can result in somewhat unpleasant side effects, however — including an aching sensation, burning, redness, and minor bleeding.
Erectile problems can happen to men of any age.  There are many factors that contribute to ED including poor health, untreated medical problems, medications and pornography use.  Many men struggle with understanding when they are experiencing situational sexual dysfunction verses when is your erectile issue an ongoing problem that requires medical help.
The observation that TRT enhances the efficacy of PDE5 inhibitors in hypogonadal men taking these therapies with suboptimal response to the PDE5 inhibitors alone has been reported.33 In addition, investigators have demonstrated that TRT in hypogonadal men can improve erectile function even without the benefit of PDE5 inhibitors.33 In addition, guidelines for managing ED in hypogonadal men by the European Association of Urology recommend controlling the man to a eugonadal state prior to initiation of PDE5 inhibitor therapy.36 Testosterone measurement consists of a serum specimen which should be ideally obtained in the morning because of the normal diurnal variation of testosterone which is at its peak in the morning. Since TRT is relatively safe, and men can potentially see an improvement in erectile function, it seems prudent to consider this issue when presented with a patient suffering from ED.
Neurogenic ED remains difficult to diagnose and treat effectively. It is important to realize that many men with neurologic disorders may have ED related to disease related factors separate from the insult to the neuro-erectile pathway. These disease related factors must be addressed prior or simultaneously with pharmacologic and/or surgical therapy to effectively treat their SD. As awareness of the complexities of normal sexual function increase so will the recognition of SD in this population. This movement will lead to improved quality of life in men with neurologic disorders, as proven by the strong link between sexual function and quality of life.
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.

Apomorphine is a non-selective D1/D2 receptor agonist with moderate efficacy and good tolerability in the treatment of mild ED (80). Apomorphine can be administered via subcutaneous injection or sublingually. However, studies have shows a lower efficacy for apomorphine compared to oral sildenafil (81,82). Apomorphine has a set role in the management of PD for non-motor symptoms, and has been reported to cause spontaneous erections and possible hypersexuality in PD men (83,84). Its role in the management of ED has been postulated for men with PD but should be considered as an alternative to sildenafil.
The medications are extremely effective, which is very good. And the medications are, for the most part, extremely well-tolerated. But there are, like with any medications, a potential downside. The one absolute downside to the use of any of these erection what we call PDE5 medications is if a patient is using a nitroglycerin medication. And nitroglycerins are used for heart disease and for angina, for the most part, although there are some recreational uses of nitrites. And that’s important because your blood vessels will dilate and your blood pressure will drop. And that is an absolute contraindication.
ED is a common occurrence after SCI, occurring in up to 80% of men, and results from disruption of the nerve pathways essential for erection (24,25). Different degrees of ED may occur depending on the spinal cord level of injury (LOI), extent of lesion and timing from injury. Reflexogenic erections can occur with lesions above L3 or L4 when the erectile spinal reflex arc remains intact. Psychogenic erections can occur with low lesions in the sacral and lumbar spinal cord but may not occur in complete lesions above T9 that can damage sympathetic outflow. Additionally, reflexogenic erections are not likely to occur in the spinal shock period that occurs after the initial cord trauma. Conversely, their occurrence may signal that the period of shock is over (26). Typically SCI affects younger men in their “sexual prime” and ED is associated with decreased quality of life (27).
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.
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