Erectile Dysfunction

Introduction

Erectile dysfunction (ED) is the persistent failure (minimum of 3 months) to achieve a penile erection suitable for sexual intercourse. Patients often refer to it as impotence.

• ED can result from an abnormality in one of the four systems necessary for a normal penile erection or from a combination of abnormalities. Vascular, nervous, or hormonal etiologies of ED are referred to as organic ED. Abnormality of the fourth system (i.e., patient’s psychological receptivity to sexual stimuli) is referred to as psychogenic ED.
• The penis has two corpora cavernosa and one corpus spongiosum which contain interconnected sinuses that fill with blood to produce an erection.
• Acetylcholine works with other neurotransmitters (i.e., cyclic guanylate monophosphate, cyclic adenosine monophosphate, and vasoactive intestinal polypeptide) to produce penile arterial vasodilation and ultimately an erection.

Clinical Presentation

• Signs and symptoms of ED can be difficult to detect. The patient’s partner is often the first to report ED to the healthcare provider.
• Nonadherence to drugs thought to cause ED can be a sign of ED.

Diagnosis

• Key diagnostic assessments include ED severity, medical and surgical history, concurrent medications, physical examination, and laboratory tests (i.e., serum blood glucose, lipid profile, and testosterone level).
• Assess the severity of ED with a standardized questionnaire.
• Complete a cardiovascular risk assessment before initiating ED therapy in men older than 50 years and in those at intermediate and high risk for cardiovascular disease.

Treatment

• Goal of Treatment: The goal is to improve the quantity and quality of penile erections suitable for intercourse.
• The first step in management of ED is to identify and, if possible, reverse underlying causes. Psychotherapy can be used as monotherapy for psychogenic ED or as an adjunct to specific treatments.
• Treatment options include vacuum erection devices (VEDs), drugs, and surgery. Although no option is ideal, the least invasive options are chosen first.

Nonpharmacologic Treatment

Vacuum Erection Device

• First-line therapy for older patients in stable relationships. Onset of action is slow (i.e., 3–20 minutes).
• An erection can be prolonged through use of constriction bands or tension rings.
• Consider VEDs as second-line therapy after failure of oral or injectable drugs. Response rate improves with addition of alprostadil or a phosphodiesterase inhibitor (PI).
• VEDs are contraindicated in patients with sickle cell disease. Use cautiously in patients on warfarin because, through a poorly understood and idiosyncratic mechanism, it can cause priapism.

Surgery

• Surgical insertion of a penile prosthesis, the most invasive treatment for ED, is used after failure of less invasive treatments and for patients who are not candidates for other treatments.
• Adverse effects of prosthesis insertion include early- and late-onset infection, mechanical failure, and erosion of the rods through the penis.

Pharmacologic Treatments

• Available agents (avanafil, sildenafil, tadalafil, and vardenafil)

Testosterone transdermal spray (Fortesta) Four sprays (equivalent to 40 mg testosterone) once daily

• Testosterone-replacement regimens restore serum testosterone levels to the normal range (300–1100 ng/dL; 10.4–38.2 nmol/L). These regimens are indicated for symptomatic patients with hypogonadism as confirmed by both a decreased libido and low serum testosterone concentrations.

Alprostadil is approved as monotherapy for the management of ED.

Unapproved Agents

• A variety of commercially available and investigational agents have been used for management of ED. Examples include trazodone (50–200 mg/day), yohimbine (5.4 mg three times daily), papaverine (7.5–60 mg [single-agent therapy] or 0.5–20 mg [combination therapy] intracavernosal injection), and phentolamine (1 mg [combination therapy] intracavernosal injection).