Factors that mediate contraction in the penis include noradrenaline, endothelin-1, neuropeptide Y, prostanoids, angiotensin II, and others not yet identified. Factors that mediate relaxation include acetylcholine, nitric oxide (NO), vasoactive intestinal polypeptide, pituitary adenylyl cyclase–activating peptide, calcitonin gene–related peptide, adrenomedullin, adenosine triphosphate, and adenosine prostanoids.
Sildenafil (Viagra) was the first oral phosphodiesterase type 5 (PDE5) inhibitor approved by the FDA in the United States for the treatment of erectile dysfunction (it is not approved for women). Sildenafil inhibits PDE5, which is an enzyme that destroys cGMP. By inhibiting the destruction of cGMP by PDE5, sildenafil allows cGMP to accumulate. The cGMP in turn prolongs relaxation of the smooth muscle of the corpora cavernosa. Relaxation of the corpora cavernosa smooth muscle allows blood to flow into the penis resulting in increased engorgement of the penis. In short, sildenafil increases blood flow into the penis and decreases blood flow out of the penis.
Just as certain meds can make it difficult for men to have an orgasm, some can keep the flagpole from even getting raised in the first place. Anti-depressant medications like Prozac and Zoloft, anti-anxiety pills like Valium, high blood pressure medicine like Diuril, and even over-the-counter cold medicines like Sudafed and anti-heartburn pills like Zantac can inhibit erections.
Erectile dysfunction is clearly a symptom of many conditions, and certain risk factors have been identified, some of which may be amenable to prevention strategies. Diabetes mellitus, hypogonadism in association with a number of endocrinologic conditions, hypertension, vascular disease, high levels of blood cholesterol, low levels of high density lipoprotein, drugs, neurogenic disorders, Peyronie's disease, priapism, depression, alcohol ingestion, lack of sexual knowledge, poor sexual techniques, inadequate interpersonal relationships or their deterioration, and many chronic diseases, especially renal failure and dialysis, have been demonstrated as risk factors. Vascular surgery is also often a risk factor. Age appears to be a strong indirect risk factor in that it is associated with an increased likelihood of direct risk factors. Other factors require more extensive study. Smoking has an adverse effect on erectile function by accentuating the effects of other risk factors such as vascular disease or hypertension. To date, vasectomy has not been associated with an increased risk of erectile dysfunction other than causing an occasional psychological reaction that could then have a psychogenic influence. Accurate risk factor identification and characterization are essential for concerted efforts at prevention of erectile dysfunction.
Surgery of the penile venous system, generally involving venous ligation, has been reported to be effective in patients who have been demonstrated to have venous leakage. However, the tests necessary to establish this diagnosis have been incompletely validated; therefore, it is difficult to select patients who will have a predictably good outcome. Moreover, decreased effectiveness of this approach has been reported as longer term followups have been obtained. This has tempered enthusiasm for these procedures, which are probably therefore best done in an investigational setting in medical centers by surgeons experienced in these procedures and their evaluation.
PDE 5 inhibitors are broken down primarily by enzyme, cytochrome P450enzyme CYP3A4. Medications that decrease or increase the activity of CYP3A4 may affect levels and effectiveness of PDE 5 inhibitors. Such drugs include medications for the treatment of HIV (protease inhibitors) and the antifungal medications ketoconazole and itraconazole. Thus caution is recommended.
In fact, one common reason many younger men visit their doctor is to get erectile dysfunction medication. Often, men with erectile dysfunction suffer with diabetes or heart disease, or may be sedentary or obese, but they don’t realize the impact of these health conditions on sexual function. Along with erectile dysfunction treatment, the doctor may recommend managing the illness, being more physically active, or losing weight.
Besides treating the underlying causes such as potassium deficiency or arsenic contamination of drinking water, the first line treatment of erectile dysfunction consists of a trial of PDE5 inhibitor (such as sildenafil). In some cases, treatment can involve prostaglandin tablets in the urethra, injections into the penis, a penile prosthesis, a penis pump or vascular reconstructive surgery.
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.
Kimberly Hildebrant, ARNP is a board certified Family Nurse practitioner. She graduated with a Bachelor of Science in Nursing from the University of Pittsburgh and a Masters in Nursing from Duquesne University. She has practiced as a nurse practitioner in the field of Infectious Disease as well as HIV for 4 years. She has over 13 years of experience as a critical care nurse. Kimberly is passionate about providing affordable healthcare to all individuals to ensure that all can live their best life. She is an advocate for preventative care and early treatment to avoid lasting illness.
A rigid or nearly rigid erectile response to intracavernous injection of pharmacologic test doses of a vasodilating agent (see below) indicates adequate arterial and veno-occlusive function. This suggests that the patient may be a suitable candidate for a trial of penile injection therapy. Genital stimulation may be of use in increasing the erectile response in this setting. This diagnostic technique also may be used to differentiate a vascular from a primarily neuropathic or psychogenic etiology. Patients who have an inadequate response to intracavernous pharmacologic injection may be candidates for further vascular testing. It should be recognized, however, that failure to respond adequately may not indicate vascular insufficiency but can be caused by patient anxiety or discomfort. The number of patients who may benefit from more extensive vascular testing is small, but includes young men with a history of significant perineal or pelvic trauma, who may have anatomic arterial blockage (either alone or with neurologic deficit) to account for erectile dysfunction.
For the patient whose history suggests organic impotence, further history, physical and laboratory data will help identify the cause. The classification listed in Table 187.2 is based on the pathophysiologic scheme presented above, and includes mechanical problems that can interfere with erection. Vascular disease is the most common cause of impotence. In advanced cases, Lehriche's syndrome of aortoiliac occlusion will be suggested by bilateral thigh or calf claudication, loss of muscle mass in the buttocks and legs, and impotence. However, the majority of patients with vascular impotence have less severe vascular disease and many will have occlusive disease of the hypogastric-cavernous bed only. Even among patients without claudication, vascular disease is still a likely cause of impotence, especially if risk factors for atherosclerosis are present. Nonatherosclerotic disease is a consideration in the patient with a history of trauma or radiation to the pelvis, both of which cause fibrosis of vessels.
In the short term, alcohol relaxes muscles in the penis, letting blood to flow in (which is a good thing). However, alcohol also prevents other blood vessels from closing and trapping all the extra blood. Erections depend on trapping increased blood flow in the erectile tissue of the penis. If you don’t trap that extra blood, you don’t get an erection. In the long run, excessive alcohol consumption can cause liver scarring, high blood pressure, and can damage your blood vessels resulting in erectile dysfunction.
Then you have to be able to make the right diagnosis. What is the basis for their erectile dysfunction? Is it psychogenic? Is it some sort of neurological or blood vessel or hormonal issue? So you have to make a diagnosis. You have to be able to make an assessment. And then only after those things are done, then you start to think about medications.
Qaseem, A., Snow, V., Denberg, T. D., Casey, D. E., Forciea, M. A., Owens, D. K., & Shekelle, P. (2009). Hormonal testing and pharmacologic treatment of erectile dysfunction: A clinical practice guideline from the American College of Physicians. Annals of internal medicine, 151(9), 639-649. Retrieved from http://annals.org/aim/article/745155/hormonal-testing-pharmacologic-treatment-erectile-dysfunction-clinical-practice-guideline-from