Pharmacology 3rd Edition by Michael Adams , Carol Urban

Exercise 6

As the triage nurse in the emergency department, you determine the patient's chief complaint, obtain vital signs, collect past medical history information, and ask about drug and food allergies. While assessing a patient with a suspected ankle fracture, she tells you that she is allergic to codeine because it makes her nauseated and sleepy.
Is this patient experiencing an idiosyncratic reaction? Explain.