Erection dysfunction

Hirano D, Takimoto Y, Yamamoto T et al (1997) Electron microscopic study of the penile plaques and adjacent corpora cavernosa in Peyronie s disease. Int J Urol 4 274-278 lacono F, Barra S, De Rosa G et al (1993) Microstructural disorders of tunica albuginea in patients affected by Peyronie s disease with or without erection dysfunction. J Urol 150 1806-1809... 

O ED can be classified as organic, psychogenic, or mixed. Many patients may initially have organic dysfunction, but develop a psychogenic component as they cope with their inability to achieve an erection. 

Erectile dysfunction (ED) is defined as the inability to achieve or maintain an erection sufficient for sexual intercourse. The definition is very subjective due to differences in desired or needed rigidity in patients of different ages and in different types of relationships. Patients may refer to their dysfunction as impotence, but the National Institutes of Health Consensus Development Conference recommends that the term erectile dysfunction replace the term impotence due to confusion with other forms of sexual dysfunction and the negative connotation associated with the term impotence.1 Patients may also develop libido or ejaculatory disorders, but these are not considered erectile dysfunction. 

Psychogenic dysfunction occurs if a patient does not respond to psychic arousal. It occurs in up to 30% of all cases of ED. Common causes include performance anxiety, strained relationships, lack of sexual arousability, and overt psychiatric disorders such as depression and schizophrenia.5 It is postulated that the anxious or nervous man will have excessive stimulation of the sympathetic system, leading to smooth muscle contraction of arterioles and vascular spaces within erectile tissue.6 O Many patients may initially have organic dysfunction, but develop a psychogenic component as they try to cope with their inability to achieve an erection. It has been estimated that up to 80% of ED cases have an organic cause, with many having a psychogenic component as well.1... 

Erectile dysfunction The inability to achieve or maintain an erection sufficient for sexual intercourse. 

Erectile dysfunction (ED) is the failure to achieve a penile erection suitable for sexual intercourse. Patients often refer to it as impotence. 

At clinical trials, sildenafil did not work well as a treatment for angina. Instead, it was observed that it overcomes erectile dysfunction. Later, it was found that cyclic GMP also increases the level of nitric oxide, which is needed in penile erections. 

A further characteristic of this principle is that, if the activity of phosphodiesterase is decreased, the concentration of cyclic GMP will increase to an extent dependent upon the extent of the decrease in activity. This characteristic has been made use of by the pharmaceutical industry. Cyclic GMP has a vasodilatory effect and this is the case for the arterioles that supply blood to the corpus cavemosum in the penis, which controls the erection of the penis. Drugs were developed (e.g. sildenafil) that inhibits cyclic GMP phosphodiesterase and hence increases the cyclic GMP level which resnlts in vasodilation of the arterioles and an increase in the snpply of blood to the spongy tissue of the corpus cavemosum, which expands resulting in erection. This dmg has been found to be effective in some patients snffering from erectile dysfunction. This can be a particular problem in diabetic patients and more elderly men (Chapter 19). 

Adjunct to the diagnosis of erectile dysfunction (Caverject only) - Patients are monitored for the occurrence of an erection after an intracavernosal injection of alprostadil. Use a single dose of alprostadil that induces a rigid erection. 

The term impotence has been used to indicate the inability of the male to attain and maintain erection of the penis sufficient to permit satisfactory sexual intercourse. Erectile dysfunction (ED) is the preferred term. ED is a common problem, especially among older men. Perhaps a more precise term for ED is that used to signify inability of the man to achieve an erect penis as part of the multifaceted process of male sexual function. Overall, the process encompasses a variety of physical aspects with significant psychological and behavioral components. 

Headache (60%), hot flashes (55%), depression (54%), diaphoresis (45%), sexual dysfunction (21%), decreased erection (18%), lower urinary tract symptoms (13%) Occasional (10%-5%)... 

Mechanism of Action An erectile dysfunction agent that inhibits phosphodiesterase type 5, the enzyme responsible for degrading cyclic guanosine monophosphate (cGMP) in the corpus cavernosum of the penis and pulmonary vascular smooth muscle, resulting in smooth muscle relaxation and increased blood flow. Therapeutic Effects Facilitates an erection, produces pulmonary vasodilation. 

A combination of phentolamine with the nonspecific smooth muscle relaxant papaverine, when injected directly into the penis, may cause erections in men with sexual dysfunction. Long-term administration may result in fibrotic reactions. Systemic absorption may lead to orthostatic hypotension priapism may require direct treatment with an -adrenoceptor agonist such as phenylephrine. Alternative therapies for erectile dysfunction include prostaglandins (see Chapter 18), sildenafil and other cGMP phosphodiesterase inhibitors (see Chapter 12), and apomorphine. 

Intracavernosal injection or urethral suppository therapy with alprostadil (PGE1) is a second-line treatment for erectile dysfunction. Doses of 2.5-25 meg are used. Penile pain is a frequent side effect, which may be related to the algesic effects of PGE derivatives however, only a few patients discontinue the use because of pain. Prolonged erection and priapism are side effects that occur in less than 4% of patients and are minimized by careful titration to the minimal effective dose. When given by injection, alprostadil may be used as monotherapy or in combination with either papaverine or phentolamine. 

By comparison, erectile dsyfunction (ED) is an example of how social dissatisfaction can be transformed into medical dysfunction and then remedied by a pill. On the one hand, it is certainly true that, in some cases, ED is the consequence of organic causes, including peripheral vascular diseases, hypertension, drug-side effects, hormonal imbalance, and diabetes. The MMAS suggests, for example, that 10 per cent of American males have complete inability to achieve erection of the penis (Feldman et al. 1994). But ED is primarily a socially constructed condition based on a socially constructed male "problem." As one commentator has explained, " [T]he more anxiety a corporation can produce, the larger its market. In other words, worrying about ED may in fact cause ED" (Loe 2004). 

Impotence, the inability to maintain an erection sufficient for intercourse, is more properly called erectile dysfunction. Up to 20 million men in the United States have this problem to some degree. Another way of stating the problem is that for normal men living in the community who are between 40 and 70 years old, only about half do not have some degree of erectile dysfunction (Fig. 14—8). The problem worsens with age (Fig. 14—9), since 39% of 40-year-olds have some degree of impotence (5% are completely impotent), but by age 70 two-thirds have some degree of impotence (and complete impotence triples to 15%). The multiple causes of erectile... 

Intracavernosal alprostadil was effective and well tolerated in the treatment of erectile dysfunction, according to the results of a 6-month study (funded by Pharmacia Upjohn) in 848 men (mean age 52 years) with at least a 4-month history of erectile dysfunction (12). This is provided that the individual dose is established by titration and patients receive training in injection techniques and periodic supervision during treatment. An initial dose was established for each patient and the patients then administered the alprostadil themselves at home. Of 727 evaluable patients, 682 (94%) had at least one erectile response after the injection of alprostadil, and 88% of injections lead to a satisfactory sexual response. The most commonly reported adverse event was penile pain, reported by 44% of patients, but only after 8% of injections. In just over half of the patients who had penile pain, the condition was reported as mild. Prolonged erection, penile fibrosis, and priapism occurred in 8,4, and 0.9% of patients respectively. Treatment was withdrawn because of medical events in 4% of patients, and drug-related events accounted for treatment withdrawal in 2% of patients. 

Phase I trials in the United States (Figure 10.16). Although UK-92,480 appeared to be safe, it had little impact on blood pressure, heart rate, and cardiac output. In a 1992 study, some volunteers receiving multiple doses reported an increased incidence of penile erections. Preliminary data was not overwhelming, but Pfizer spent another two years investigating the potential market for an erectile dysfunction drug. A study involving 300 patients in 1994 and 1995 showed excellent results for UK-92,480, which had been... 

Erectile dysfunction Alprostadil injected into the corpus caver-nosum of the penis provides effective treatment of some forms of male impotence. The drug increases arterial inflow through vasodilation and decreases venous outflow by causing relaxation of the corporal smooth muscle that occludes draining venules. Possible side effects include pain at the site of injection and, rarely, prolonged erection. 

Erectile dysfunction, that is, the inability to maintain penile erection for the successful performance of sexual activity, has both organic and psychogenic causes, including as a sequelae to prostatic surgery. Erectile dysfunction is estimated to affect up to 30 million men in the United States. Previous therapies have included penile implants, and intrape-nile injections of alprostadil (see p. 420). Sildenafil [sil DEN a HI], the first oral drug approved for the treatment of erectile dysfunction in males, was introduced in early 1998. 

Erectile dysfunction. Sildenafil, vardenafii, and tardalafil are inhibitors of PDE-5 and are used to promote erection. During sexual arousal NO is released from nerve endings in the corpus cavernosum of the penis, which stimulates the formation of cGMP in vascular smooth muscle. PDE-5, which is important in this tissue, breaks down cGMP, thus counteracting erection. Blockers of PDE-5 "conserve cGMP. 

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