A nurse is collecting data from a client who received diphenhydramine 1 hr ago after developing an allergic reaction to trimethoprim-sulfamethoxazole. Which of the following statements by the client should indicate to the nurse that the medication is effective?

Choice A rationale Increased appetite is not a primary therapeutic effect of diphenhydramine when treating an acute allergic reaction. Diphenhydramine primarily acts as an antihistamine, blocking histamine H1 receptors to reduce symptoms like pruritus, urticaria, and angioedema. Changes in appetite are not typically a direct or expected indicator of its effectiveness in this context. Choice B rationale Hoarseness can be a manifestation of angioedema affecting the larynx, a serious symptom of an allergic reaction. Diphenhydramine's antihistaminic properties reduce vascular permeability and swelling by blocking histamine's effects on capillaries, thus alleviating laryngeal edema and improving voice quality. Its effectiveness in reducing swelling indicates a positive therapeutic response. Choice C rationale Headaches are not a typical symptom directly treated by diphenhydramine in the context of an allergic reaction. While some allergic reactions might trigger headaches, diphenhydramine's primary mechanism of action targets histamine-mediated responses, not direct analgesic effects for headache relief. Therefore, headache resolution is not a primary indicator of its effectiveness. Choice D rationale Diphenhydramine is known for its sedative properties due to its ability to cross the blood-brain barrier and block H1 receptors in the central nervous system. Therefore, feeling more alert would contradict the expected side effects and would not indicate the medication's effectiveness in managing allergic symptoms. Increased alertness would suggest an atypical or absent response.