SN instructed patient / caregiver about Diphenhydramine( Benadryl). It is a first-generation antihistamine used to treat a number of conditions including allergic symptoms and itchiness, the common cold, insomnia, motion sickness, and extrapyramidal symptoms. It is a potent anticholinergic agent. This activity is responsible for multiples side effects such as: dry mouth and throat, increased heart rate, pupil dilation, urinary retention, constipation, and, at high doses, hallucinations or delirium. Other side effects include motor impairment, flushed skin, blurred vision at near point owing to lack of accommodation, abnormal sensitivity to bright light (photophobia), sedation, difficulty concentrating, short-term memory loss, visual disturbances, irregular breathing, dizziness, irritability, itchy skin, confusion, increased body temperature, temporary erectile dysfunction, and excitability, and although it can be used to treat nausea, higher doses may cause vomiting. Report any Side effect / Adverse reaction to Physician / Nurse as needed.