Two nurses are discussing the theories of drug-receptor interaction. Which statements are true regarding the affinity of a drug and for its receptor? (Select all that apply)

Choice A reason: Dry cough is a common, not serious, side effect of ACE inhibitors due to bradykinin accumulation. While bothersome, it’s not life-threatening like angioedema. It often necessitates switching to an ARB, but calling it serious overstates the risk, making this choice incorrect.

Choice B reason: Dry cough occurs in 5-20% of ACE inhibitor users but doesn’t typically subside with continued use, as bradykinin accumulation persists. Patients often require a medication change (e.g., to ARBs), making the claim that it will subside over time inaccurate and incorrect.

Choice C reason: Dry cough is common but not universal in ACE inhibitor users, affecting 5-20% of patients due to variable bradykinin sensitivity. Stating it occurs in all patients is inaccurate, as many tolerate ACE inhibitors without cough, making this choice incorrect.

Choice D reason: Dry cough, caused by bradykinin buildup, affects some ACE inhibitor users and is uncomfortable, often requiring a switch to an ARB, which doesn’t affect bradykinin. This accurately reflects the side effect’s impact and management, making it the correct choice for the nurse’s response.

Choice A reason: Taking antihistamines only with symptoms may reduce side effects but provides inconsistent relief, as histamine levels fluctuate. Daily use during allergy seasons prevents symptom onset, offering better control, especially for second-generation antihistamines with longer action, making this choice less effective.

Choice B reason: First-generation antihistamines (e.g., diphenhydramine) are sedating and have more side effects than second-generation (e.g., loratadine), which are equally effective for allergies but less sedating. Claiming first-generation are more effective is incorrect, as second-generation are preferred, making this choice inaccurate.

Choice C reason: Anticholinergic effects (e.g., dry mouth) are more common with first-generation antihistamines (e.g., diphenhydramine) due to non-selective receptor binding. Second-generation antihistamines (e.g., cetirizine) are more selective for H1 receptors, reducing these effects, making this choice incorrect and opposite to pharmacological profiles.

Choice D reason: Daily oral antihistamines, especially second-generation (e.g., loratadine), during allergy seasons maintain steady histamine receptor blockade, preventing symptoms like sneezing and itching. This maximizes efficacy and improves quality of life, aligning with guidelines for seasonal allergies, making this the correct nurse response.