A 45-year-old man on trazodone for insomnia develops a prolonged, painful erection lasting 4 hours. This adverse effect is due to blockade of which receptor?
- A Muscarinic
- B Alpha-2 adrenergic
- C Alpha-1 adrenergic ✓
- D Dopamine D2
Correct answer: C. Alpha-1 adrenergic
Explanation
Trazodone is an alpha-1 adrenergic antagonist. Blockade of these receptors in the corpus cavernosum prevents detumescence, leading to priapism, a urological emergency. This effect is rare but well recognized and requires immediate intervention to prevent ischemic damage.
Reference: Katzung & Trevor's Pharmacology Examination and Board Review, 13th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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