A 55-year-old man with depression, anxiety, BPH, and angina on multiple medications reports erectile dysfunction. Which medication is the most likely contributor to his ED?

• A. Nitroglycerin
• B. Prazosin
• C. Selegiline
• D. Duloxetine

Answer: (D)

Erectile dysfunction from medications often comes from antidepressants that increase serotonin. Serotonin can inhibit sexual function, including arousal and erection, by dampening dopaminergic pathways and altering CNS signaling involved in sexual response. Duloxetine is an SNRI used for depression and anxiety, and sexual side effects such as erectile dysfunction are a well-recognized part of its profile.

Nitroglycerin doesn’t typically cause erectile dysfunction; it mainly affects vessels in a way that can lead to headaches and hypotension. Prazosin can cause orthostatic symptoms and is not a common cause of ED. Selegiline, an MAOI, can have sexual side effects, but among these drugs, duloxetine is the most strongly associated with erectile dysfunction, making it the most likely contributor in this patient.