Erectile Dysfunction

A normal sexual erectile response is initiated by parasympathetic and sympathetic neuronal triggers that integrate physiologic stimuli of the penis with sexual desire.31,32 In associations with parasympathetic stimuli, nitric oxide produced by endothelial cells triggers a molecular cascade that results in smooth muscle relaxation and arterial influx of blood into the corpus cavernosum.31,32 This is followed by compression of venous return, which produces the erection.

ED is defined as the inability to achieve or maintain an erection sufficient for satisfactory sexual performance.31,32 ED may result from advancing age, cardiovascular diseases, hypertension, diabetes mellitus, hormonal disorders, prescription and recreational drug use, neurologic conditions (e.g., Alzheimer’s disease, Parkinson’s disease), psychological problems (e.g., anxiety, depression), obesity, sedentary lifestyle, cigarette smoking, and many drugs.31,32

First-line therapy for ED is aimed at lifestyle changes directed at increased physical activity, weight loss, and smoking cessation; and modifying pharmacotherapy that may contribute to ED.31,32 Pharmacotherapy with sildenafil or tadalafil, which inhibit phosphodiesterase type 5 (PDE5) responsible for degradation of cGMP enhances the effect of nitric oxide and result in smooth muscle relaxation and inflow of blood to the corpus cavernosum.2,3,31,32