A 61-year-old woman comes to the emergency department because of a 2-hour history of headache, nausea, blurred vision for the last 2 days. She has had similar symptoms in the past. Her vital signs are within normal limits. he starts taking diphenhydramine several days ago for seasonal allergies. On physical examination, there is edema and clear drainage affecting the nasal mucosa. Funduscopic examination is normal. This patient's visual symptoms are most likely due to blockade of which of the following mediators?

Question

A 61-year-old woman comes to the emergency department because of a 2-hour history of headache, nausea, blurred vision for the last 2 days. She has had similar symptoms in the past. Her vital signs are within normal limits. he starts taking diphenhydramine several days ago for seasonal allergies. On physical examination, there is edema and clear drainage affecting the nasal mucosa.  Funduscopic examination is normal.  This patient's visual symptoms are most likely due to blockade of which of the following mediators?

Quizplus · Accepted Answer

Eductional Objective: In addition to blocking histamine receptors, first-generation antihistamines (eg, chlorpheniramine, diphenhydramine) have antimuscarinic, anti-alpha adrenergic, and anti-serotonergic properties.  Anticholinergic effects on the ocular ciliary muscles impair accommodation and cause blurring of vision for close objects.

A 61-Year-Old Woman Comes to the Emergency Department Because of a 2-Hour