A 75-year-old man comes to the urgent care center with acute onset of a pruritic rash after eating strawberries. The patient has no associated swelling in or around the mouth, no wheezing, and no difficulty breathing. Past medical history is notable for coronary artery disease, for which he takes atorvastatin, lisinopril, aspirin, and metoprolol. He also has a history of allergy to dog and cat dander. The patient does not use alcohol or tobacco. His family reports that he lives alone and his functional status has been declining. He walks with a cane, has poor vision, and is frequently forgetful. The patient also has occasional dizziness when standing up and a history of frequent falls. Which of the following would be the most appropriate medication to treat this patient's acute symptoms?

Question

A 75-year-old man comes to the urgent care center with acute onset of a pruritic rash after eating strawberries.  The patient has no associated swelling in or around the mouth, no wheezing, and no difficulty breathing.  Past medical history is notable for coronary artery disease, for which he takes atorvastatin, lisinopril, aspirin, and metoprolol.  He also has a history of allergy to dog and cat dander.  The patient does not use alcohol or tobacco.  His family reports that he lives alone and his functional status has been declining.  He walks with a cane, has poor vision, and is frequently forgetful.  The patient also has occasional dizziness when standing up and a history of frequent falls.  Which of the following would be the most appropriate medication to treat this patient's acute symptoms?

Quizplus · Accepted Answer

This patient, with an acute, pruritic rash and history of environmental allergies, has a typical presentation of urticaria (hives). Hives are triggered in most cases by IgE-dependent mast cell degranulation. As histamine is one of the primary mediators in this type of allergic reaction, antihistamines (ie, H1 histamine receptor antagonists) are the preferred treatment in most cases. The side effects of antihistamines are largely due to blockade of other pathways, especially: These side effects are especially prominent with first-generation antihistamines (eg, hydroxyzine, promethazine, chlorpheniramine, diphenhydramine) (Choices A, B, C and E). Furthermore, first-generation antihistamines are lipophilic and easily cross the blood-brain barrier, where they may cause significant sedation and cognitive dysfunction. First-generation antihistamines are considered potentially inappropriate medications for elderly patients, especially those with pre-existing cognitive or functional impairment. Newer-generation antihistamines (eg, loratadine, cetirizine) do not have the same degree of antimuscarinic, antiserotonergic, or anti-alpha adrenergic properties and their side effects are minimal. Moreover, second-generation antihistamines are less lipophilic, do not readily cross the blood-brain barrier, and are usually nonsedating. Educational objective: First-generation antihistamines can cause significant side effects due to blockade of cholinergic, alpha-adrenergic, and serotonergic pathways. They should be avoided in older patients with cognitive or functional impairments. __________ References: Drugs with anticholinergic properties: a current perspective on use and safety. (http://www.ncbi.nlm.nih.gov/pubmed/21635190)

A 75-Year-Old Man Comes to the Urgent Care Center with Acute