The practical nurse (PN) is obtaining information from a female client who is starting a new prescription for conjugated estrogens 0.625 mg PO daily. Prior to the client taking the first dose of the medication, which information should the PN obtain?

Choice A reason: Diphenhydramine does not facilitate rapid transfusion. It is an antihistamine used to prevent allergic reactions during transfusions, not to alter infusion speed. Rapid infusion depends on clinical protocols and patient tolerance, not antihistamine effects, making this choice incorrect.

Choice B reason: Diphenhydramine does not inhibit antigen-antibody reactions, which occur in transfusion mismatches. It mitigates histamine-mediated allergic symptoms, like itching or hives, but does not prevent immunological reactions. This choice is incorrect, as it misrepresents the drug’s role in symptom management.

Choice C reason: While diphenhydramine may cause sedation, its primary purpose before transfusion is to prevent allergic reactions, not to promote relaxation. Relaxation is a secondary effect, not the clinical rationale for its use, making this choice less accurate than allergy prevention.

Choice D reason: Diphenhydramine, an antihistamine, minimizes allergic reaction symptoms, such as itching or hives, during blood transfusions by blocking histamine receptors. This premedication reduces the risk of mild transfusion-related allergic responses, ensuring patient comfort and safety, making it the correct explanation.

Choice A reason: Serum lithium levels indicate compliance but do not directly explain the need for frequent monitoring. Lithium’s therapeutic effect stabilizes mood, but monitoring is primarily due to its narrow therapeutic index, where small changes in blood levels can cause toxicity, not just behavioral changes or compliance.

Choice B reason: Sodium levels affect lithium excretion, as both compete for renal reabsorption. Low sodium increases lithium retention, risking toxicity, while high sodium increases excretion, reducing efficacy. Lithium’s narrow therapeutic range (0.6–1.2 mEq/L) necessitates frequent monitoring to prevent toxic levels, which can cause neurological or cardiac issues.

Choice C reason: Myelosuppression and agranulocytosis are not common lithium side effects. Lithium may cause mild leukocytosis, not suppression. Toxicity risks, like neurological or renal effects, drive monitoring needs, not hematologic issues. This choice is incorrect, as it misrepresents lithium’s side effect profile.

Choice D reason: Tyramine, relevant to monoamine oxidase inhibitors, does not influence lithium metabolism. Lithium’s pharmacokinetics are affected by sodium and renal function, not dietary tyramine. This choice is incorrect, as it falsely links a dietary factor to lithium’s monitoring requirements.