A 61-Year-Old Woman Who Has Had an Upper Respiratory Infection

A 61-year-old woman who has had an upper respiratory infection for several weeks has presented to her family physician with complaints of a recent onset of urinary retention. She reveals to her physician that she has been taking nonprescription cold medications over and above the suggested dose for the past 2 weeks. Which of the following phenomena will her physician most likely suspect is contributing to her urinary retention?

A) Cholinergic actions of the cold medicine are triggering internal and external sphincter contraction.
B) Antihistamine effects inhibit communication between the pons and the thoracolumbar cord.
C) The anticholinergic effects of the medication are impairing normal bladder function.
D) Over-the-counter medications such as cold medicine stimulate the parasympathetic nervous system and inhibit bladder emptying.