The practical nurse (PN) is caring for a client with Alzheimer’s disease who has a new prescription for donepezil. The family asks the PN how this will help their relative. Which explanation provided by the PN accurately describes the action of the medication?

Choice A reason: A neurological exam assesses brain function but does not directly address glipizide-related symptoms like confusion and blurred vision, which suggest hypoglycemia. Glipizide, a sulfonylurea, lowers blood glucose, and these symptoms are likely due to low glucose levels, making glucose testing more urgent than a neurological evaluation.

Choice B reason: Administering glucagon treats severe hypoglycemia but is premature without confirming low blood glucose. Glipizide increases insulin release, potentially causing hypoglycemia, but a fingerstick glucose test is needed first to verify the cause of symptoms. This choice is incorrect without diagnostic confirmation.

Choice C reason: Measuring vital signs provides general health data but does not specifically address confusion and blurred vision caused by glipizide-induced hypoglycemia. Low blood glucose is the likely cause, and testing glucose levels is more direct and urgent than monitoring vital signs, which are secondary in this context.

Choice D reason: Obtaining a fingerstick blood glucose is critical, as glipizide can cause hypoglycemia, leading to confusion and blurred vision. These symptoms result from insufficient glucose in the brain and eyes. Confirming low glucose guides immediate treatment, such as glucose administration, making this the most appropriate action.

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.