Final answer:
Atropine is contraindicated in men with BPH because it can lead to urinary retention by relaxing the bladder neck and prostate muscles, exacerbating symptoms of BPH.
Step-by-step explanation:
You shouldn't prescribe atropine to a male with BPH (benign prostatic hyperplasia) because atropine can exacerbate symptoms of BPH. Atropine is a muscarinic antagonist which means that it blocks muscarinic acetylcholine receptors. This blocking affects various parts of the body, but crucially it can cause the smooth muscles in the bladder neck and prostate to relax, making it even more difficult to urinate. In patients with BPH, this can lead to acute urinary retention, a condition which requires urgent medical attention. Since BPH involves prostate enlargement, the use of atropine would generally be avoided to prevent worsening the symptoms associated with BPH.