For each clinical finding, click to specify whether the finding indicates or does not indicate a therapeutic effect of diphenhydramine

• Decreased sneezing: Diphenhydramine, an H1 receptor antagonist, reduces histamine-mediated symptoms of allergies, including sneezing. A decrease in sneezing demonstrates that the medication is effectively controlling the allergic response. This is a direct therapeutic effect of antihistamine administration. • Tearing of the eyes: Persistent tearing is a symptom of allergic reactions and indicates that diphenhydramine is not fully alleviating the allergic response. Continued eye tearing does not reflect a therapeutic effect and may require adjunctive therapy. • Presence of urticaria: The continued presence of urticaria (hives) indicates that the allergic reaction is ongoing. Diphenhydramine is intended to relieve urticaria, so its persistence shows that the medication has not yet achieved the desired therapeutic effect. • Increased cough: An increase in coughing does not reflect the effectiveness of diphenhydramine, as cough is not a primary target symptom for this antihistamine unless histamine-mediated. Worsening cough suggests inadequate symptom control or another underlying cause.