Treatment of men suffering from sexual dysfunction should be patient centered and goal oriented. Lifestyle modification and reduction of cardiovascular risk factors are important components of treatment and should include smoking cessation; reduction of alcohol intake; diet; exercise; and treatment of diabetes, dyslipidemia, and hypertension. Men who have a psychogenic component to their erectile dysfunction or who are experiencing emotional distress will benefit from sexual health therapy or counseling.
In men with hypogonadism who have undergone complete endocrinologic evaluation, restoration of normal testosterone levels may improve sexual quality of life (see Male Hypogonadism in Chapter 26.)
Sexual stimulation causes the release of nitric oxide from the parasympathetic nerves and cavernosal arterial endothelium thereby initiating penile erection. Upon entering smooth muscle cells, nitric oxide stimulates cyclic guanosine monophosphate (cGMP) production, with subsequent intracellular calcium sequestration and cellular hyperpolarization. Phosphodiesterase type 5 (PDE-5) degrades cGMP, causing penile detumescence. Activation of pelvic sympathetic nerves causes ejaculation, contraction of the smooth muscle within the corpora cavernosa and detumescence.
Sildenafil, vardenafil, tadalafil, and avanafil inhibit phosphodiesterase type 5 (PDE-5), preventing the degradation of cGMP and increasing blood flow into the penis. While generally similar in their effectiveness, these medications have variable durations of onset, activity, and side effects. Each medication should be initiated at the lowest dose and titrated to achieve the desired effect. There is no impact on libido and priapism is exceedingly rare. These medications are contraindicated in patients taking nitroglycerin or nitrates, since there may be exaggerated cardiac preload reduction causing hypotension and syncope. All patients being evaluated for acute chest pain should be asked about the use of PDE-5 inhibitors before administering nitroglycerin and close monitoring of blood pressure is warranted if there is concern regarding medication overlap.
The combination of PDE-5 inhibitors and alpha-receptor blockers (prescribed for lower urinary tract symptoms) may cause a larger reduction in systemic blood pressure than when PDE-5 inhibitors are used alone. However, these two classes of medication may be safely used in combination if they are initiated and titrated in a stepwise fashion.
2. Injectable or suppository medications
Injection of prostaglandin E2 into the corpora cavernosa is an acceptable form of treatment for many men with erectile dysfunction. Injections are performed using a tuberculin-type syringe or a metered-dose injection device. The base and lateral aspect of the penis is used as the injection site to avoid injury to the superficial blood and nerve supply located dorsally. Complications are rare and include priapism, penile pain, bruising, fibrosis, and infection. Prostaglandin E2 (alprostadil) can also be delivered via an intraurethral suppository. Prostaglandin E2 is often compounded with papaverine, phentolamine, or atropine in order to increase effectiveness. Patients using such compounded agents should be cautioned about the increased risk of priapism and variability of drug effect due to differences in compounding.
Priapism requires immediate medical attention to prevent ischemia and fibrosis of the cavernosal tissues. Initial treatment is aspiration of blood from the penis and the injection of sympathomimetic drugs (epinephrine or phenylephrine); if these maneuvers are not successful, surgical arteriovenous shunts should be performed to restore blood flow to the penis.
C. Vacuum Erection Device
The vacuum erection device creates negative pressure around the penis, drawing blood into the corpora cavernosa. Once tumescence is achieved, an elastic constriction band is placed around the penile base to prevent loss of erection. Such devices are effective but may cause penile discomfort leading to a high rate of disuse. Serious complications are rare.
D. Penile Prosthetic Surgery
Penile prostheses are implanted directly into the paired corpora cavernosa and may be semi-rigid (malleable) or inflatable. The inflatable devices are most commonly used and result in a natural appearance and function because they emulate the tumescence and detumescence of the normal erection. Complications of surgery are rare but include mechanical failure and infection. For men who elect this treatment, personal and partner satisfaction rates are very high due to enhanced spontaneity and reliability of erections.
E. Vascular Reconstruction
Patients with disorders of the arterial system may be considered for arterial bypass procedures utilizing arterial (epigastric) or venous (deep dorsal vein) segments for distal occlusion. Such procedures should only be performed on select men under 55 years of age with focal arterial occlusion resultant from trauma. Rare patients with congenital venous occlusion disorders, heralded by lifelong erectile dysfunction, may be managed with ligation of the crura of the corpora cavernosa. Experience with vascular reconstructive procedures is limited, and many patients so treated still fail to achieve a rigid erection.
F. Medical and Surgical Therapy for Peyronie Disease
Oral medications for Peyronie disease have not been approved by the FDA; however, off-label use of multiple vasodilatory, anti-inflammatory, and antioxidant medications is common. Injectable collagenase Clostridium histolyticum is the only FDA-approved medication for the treatment of Peyronie disease. Collagenase enzymatically severs disordered collagen fibers after injection into the central portion of the penile plaque. Surgical treatment is an alternative for men with compromised sexual function due to severe curvature, lesions causing penile instability, or with inadequate results from collagenase. The choice of corrective procedure should be tailored to each patient after a detailed evaluation of disease severity and sexual function.