The initial event for normal erectile function is sexual stimulation. Subsequent to processing in the central nervous system neural impulses are conveyed along the spinal cord, exiting through the pelvic parasympathetic preganglionic nerves. These pelvic nerves form the pelvic plexus and send their message through first messenger, acetyl choline, to the cavernosal nerves. The cavernosal nerves enter erectile bodies (corpora cavernosa) (Figure 1). Here, their nerve endings release a second messenger, nitric oxide. Nitric oxide activates the enzyme guanylyl cyclase, which lyses guanosine triphosphate (GTP) to produce a third messenger, the intracellular cyclic guanosine monophosphate (cGMP). Ultimately, the result is a decrease of intracellular calcium and an opening of potassium channels with the resultant relaxation of vascular smooth muscle in the arteries, aterioles, and sinusoids of the corpora cavernosa. The sinusoids open and rapidly fill with blood. Finally, the distended sinusoids compress their drainage pathways (venules) against the fibroelastic covering of the cavernosal bodies (tunica albuginea) and trap the blood in cavernosal bodies. The combination of an increased inflow of blood into the penis and coincident markedly diminished outflow results in rapidly increasing intracavernosal pressure that ultimately approximates systolic pressure. At this pressure the penis has sufficient axial rigidity to permit vaginal penetration.
Crossref | PubMed | Scopus (24) | Google ScholarSee all References Almost every class of antihyper-tensive medication has been implicated in causing ED; however, most of these studies, published as case reports or patient surveys, have been relatively subjective and uncontrolled.4x4Feldman, HA, Goldstein, I, Hatzichristou, DG, Krane, RJ, and McKinlay, JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994; 151: 54–61
Penile arterial supply (top) and venous drainage (middle), longitudinal views. Bottom, Transverse and longitudinal views of venous return. From Lue TF. Physiology of penile erection and pathophysiology of erectile dysfunction and priapism. In: Walsh PC, Retik AB, Vaughan ED Jr, Wein AJ, eds. Campbell's Urology. Vol 2. 7th ed. Philadelphia, Pa: WB Saunders Co; 1998:1157-1179. With permission from Elsevier.
While a widely held perception is that CVD drugs cause ED, data attest towards the contrary and some agents may be even beneficial.41 Only thiazide diuretics lead clearly to ED, while some older beta-blockers also do so, but the side-effect of ED was very low (∼3%) when the patient was blinded for the drug administration.42 In fact, the vasodilating nebivolol may even improve erectile function.35,43 ACE-inhibitors, angiotensin-receptor blockers, and calcium-channel blockers are reported to have neutral or even a positive effect on erectile function35,41,43 but more evidence is needed. Regarding statins, the largest body of evidence point towards a beneficial effect.44 A negative effect has been reported in high statin doses, possibly related to a potential reduction in serum testosterone levels, but this dose dependency warrants further investigation. In terms of patient management, when ED onset and therapy initiation are linked and a cause-and-effect association is presumed, a short period of drug withdrawal with monitoring for ED resolution for verification may be an option. In patients who developed ED long after the initiation of CV drug treatment, sexual dysfunction is less likely to be drug associated and PDE5 inhibition therapy may be initiated.
For patients who failed oral medical therapy or unable to tolerate the side effects, intracavernosal injection of vasoactive agents can often provide effective alternative. Various vasoactive agents such as alprostadil, papaverine or phentolamine have been used either as single agent or combination agents to potentiate the NO release and cavernosal smooth muscle vasodilation. However, intracavernosal injection therapy has high attrition rate and can be associated pain especially with alprostadil injection (2). The practice of isolating compounds and understanding its pharmacological attributes before using it as a drug therapy has been a strength of Western medicine.
Crossref | PubMed | Scopus (56) | Google ScholarSee all References When matched for age, hypertension, diabetes, and tobacco use, no significant difference was noted in the presence of ED (42% in the myocardial infarction group vs 48% in the control group). However, the presence of severe congestive heart failure has been associated with increased ED. A study of 80 patients with New York Heart Association class III/IV congestive heart failure found that 40% of these patients had complete ED, and another 40% had either mild or moderate ED.15x15Taylor, HA Jr. Sexual activity and the cardiovascular patient: guidelines. Am J Cardiol. 1999; 84: 6N–10N
Sildenafil should be taken 1–2 h before intercourse. It is important to tell patients that the drug’s effectiveness requires sexual stimulation. One patient in our clinic recently complained that he had no effect from taking sildenafil. It was later discovered that he took the pill and then sat on his couch and read a book about how to grow tomatoes!
People sometimes refer to ED as "impotence," although the two aren't really the same condition. ED is the physical inability to develop or maintain an erection that is rigid enough for sex. Impotence is a broader term. While one cause of it is ED, impotence may also involve a lack of sexual desire, an inability to ejaculate, or problems with orgasm.
In particular, patients are classified into three categories (low, intermediate, high) depending on their CV risk profile. Individuals with controlled hypertension belong to the low-risk group where sexual dysfunction can be safely managed with the approved medical therapies regardless of the number or class (with the exception of b-blockers and diuretics) of agents of the patient’s antihypertensive regime. Moreover, patients of this group can safely initiate or reinstitute sexual activity without any need for additional cardiovascular evaluation.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References During this period, 130 deaths were reported to the US FDA; 41 of these men died or had cardiac arrest within 4 to 5 hours after taking sildenafil, and 27 died or had cardiac arrest either during or immediately after sexual activity. The average age of these men was 64 years. Of the 77 men in this group who died of documented cardiovascular-related events, 41 died of definite or suspected myocardial infarction, 27 died after cardiac arrest, and 6 had symptoms of cardiac disease at the time of death. Sixteen of the men had taken nitroglycerin or organic nitrates in association with sildenafil; another 3 had nitroglycerin in their possession at the time of death. In 48 men, the cause of death was unknown, and another 3 died of cerebrovascular accidents. Overall, it was concluded that sildenafil was not associated with an excess of cardiovascular death.
ED almost always has an organic or mixed etiology in diabetic men. This often results in diabetic men reporting more severe ED when they present for treatment of this condition. It is not surprising, therefore, to learn that diabetic men's responses to standard therapy for ED differ from those of the general population of men with ED.38 We, therefore, will now briefly review the literature regarding effectiveness of various ED therapies specifically in diabetic men.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Sildenafil has a 4000-fold increased selectivity for PDE-5 over PDE-3, has negligible effects on heart rate, and has only a modest effect on blood pressure level in healthy persons, with an average systolic pressure decrease of 10 mm Hg with a single dose of 100 mg.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
Viagra, Cialis, Levita, and Staxyn all work in a similar fashion and make it physically possible to get an erection when aroused. However, men whose blood pressure is poorly controlled and who take alpha-blockers for high blood pressure treatment should not take any of these treatments for erectile dysfunction as it may reduce blood pressure to critically low levels, causing fainting or sudden death. Also, you may be prohibited to use these drugs if you demonstrate any of the following:
It’s crucial that any underlying medical condition, such as angina or diabetes, is detected. So if you’re experiencing problems with ED, book an appointment with your doctor. He or she will assess and examine you to try to establish the cause of the problem, and may refer you for tests. Don’t take any medicine for ED without first discussing it with your doctor.
At the same time, people with diabetes are susceptible to a type of blood vessel damage known as endothelial dysfunction. A recent study found that men with ED are at a greater risk of heart disease, which is also associated with endothelial dysfunction. If blood vessels aren't in good working order, the penis may not get enough blood for an erection.
Eastern medicine should be fully exploited, and integrated with modern medicine to combine the advantages of both TCM and Western medicine. More research should be conducted into the efficacy and safety of TCM, and integration of TCM and Western medicine may provide promising breakthroughs in future clinical treatment. This strategy may allow for the development of new therapeutic strategies based on concepts of TCM and integrated medicine. There is a need for multimodal therapy and holistic approach to treat men (and their partners) with ED through complementary use of herbal supplements and modern drug to optimize underlying medical comorbidities; acupuncture, exercise or massage to reduce stress and strengthen the body; introduction and escalation of various medical therapy with use of mechanical therapy to further enhance penile erection; and lastly surgical intervention in suboptimal or refractory ED cases.
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