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  • 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 any single abnormality or combination of abnormalities of the four systems necessary for a normal penile erection. Vascular, neurologic, or hormonal etiologies of ED are referred to as organic ED. Patients who do not respond to psychogenic stimuli and have no organic cause for dysfunction have 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 (ie, cyclic guanylate monophosphate, cyclic adenosine monophosphate, and vasoactive intestinal polypeptide) to produce penile arterial vasodilation and ultimately an erection.

  • Organic ED is associated with diseases that compromise vascular flow to the corpora cavernosum (eg, peripheral vascular disease, arteriosclerosis, and essential hypertension), impair nerve conduction to the brain (eg, spinal cord injury and stroke), or impair peripheral nerve conduction (eg, diabetes mellitus). Secondary ED is associated with hypogonadism.

  • Psychogenic ED is associated with malaise, reactive depression or performance anxiety, sedation, Alzheimer disease, hypothyroidism, and mental disorders. Patients with psychogenic ED generally have a higher response rate to interventions than those with organic ED.

  • Social habits (eg, cigarette smoking and excessive ethanol intake) and medications (Table 80–1) can also cause ED.

TABLE 80–1Medication Classes That Can Cause Erectile Dysfunction

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