Erectile Dysfunction

Erectile dysfunction (ED), also referred to as impotence, is the inability to attain and/or maintain an erection sufficient for satisfactory sexual intercourse. Sexual dysfunction is a more general term that also includes disorders of libido (sexual urge), orgasmic dysfunction, and ejaculatory dysfunction in addition to the inability to attain or maintain penile erection. A survey showed that 52% of men between the ages of 40 and 70 were affected by erectile dysfunction of some degree.

Population based studies indicate that the best predictors of the risk of ED are age, history of diabetes mellitus, hypertension, medication use, and cardiovascular disease.Advancing age is an important risk factor for ED in men: less than 10% of men younger than 40 years and more than 50% of men older than 70 years have ED.

Among the chronic diseases associated with ED, diabetes mellitus is the most important risk factor. The age-adjusted risk of complete ED was three times higher in men with a history of diabetes mellitus than in those without a history of diabetes mellitus. Fifty percent of men with diabetes mellitus will experience ED at some time during the course of their illness.

Heart disease, hypertension, and hyperlipidemia were associated with significantly increased risk of ED.  Cardiovascular disorders, including hypertension, stroke, coronary artery disease, and peripheral vascular disease, are all associated with increased risk of ED. Physical activity is associated with reduced risk of ED.

Several reviews have emphasized the relationship of prescription medications and the occurrence of ED. IThiazide diuretics and psychotropic drugs used to treat depression may be the most common drugs associated with ED simply because of the high prevalence of their use. However, a variety of drugs, including almost all antihypertensives, digoxin, H2-receptor antagonists, anticholinergics, cytotoxic agents, and androgen antagonists, have been implicated in the pathophysiology of ED.

Recent surveys have revealed an association of lower urinary tract symptoms with erectile dysfunction, even after adjusting for age and other risk factors. The presence and severity of lower urinary tract symptoms is an independent predictor of ED. There is growing evidence that the two conditions may be mechanistically linked, because the biochemical mechanisms that regulate bladder detrusor and cavernosal smooth muscle function share many similarities.

The diagnostic evaluation of a man with ED usually includes measurements of hemoglobin, white blood count, blood glucose, blood urea nitrogen (BUN) and creatinine, plasma lipids, and testosterone levels.

If the history, physical exam, and ED questionnaire do not identify any obvious medical concerns needing further workup, then a cost-effective approach is to prescribe a trial of oral PDE5 inhibitor provided there are no contraindications (e.g., nitrate use).