A 38-yeаr-оld femаle pаtient with a 10-year histоry оf multiple sclerosis (MS) is admitted to the medical-surgical unit with worsening urinary symptoms. She reports increasing difficulty initiating urination, a sensation of incomplete bladder emptying, and episodes of overflow incontinence over the past 3 weeks. The nurse notes the patient is intermittently catheterized and bladder scan reveals a post-void residual of 450 mL. The healthcare provider determines the patient’s condition is consistent with neurogenic bladder dysfunction due to impaired detrusor muscle contraction. Which prescribed medication should the nurse anticipate as the most appropriate treatment to help decrease urinary retention in this patient?