A nurse is reviewing medication for a patient with a recent myocardial infarction. The physician has prescribed aspirin. What is the primary purpose of this medication in this context?

Choice A reason: Administering the medication with meals only is not a valid adjustment for a medication that is primarily excreted by the kidneys. The food intake does not affect the renal clearance of the drug, unless it alters the pH of the urine or the blood flow to the kidneys. The nurse should follow the instructions on the medication label or the prescriber's order regarding the timing of the administration.

Choice B reason: No dose adjustment is required is an incorrect statement for a medication that is primarily excreted by the kidneys. The renal impairment can reduce the elimination of the drug and increase its concentration in the blood. This can cause adverse effects and toxicity. The nurse should consult with the prescriber or the pharmacist about the appropriate dose reduction or frequency change for the patient's level of renal function.

Choice C reason: Increasing the dose to ensure therapeutic effect is a dangerous and inappropriate adjustment for a medication that is primarily excreted by the kidneys. The renal impairment can reduce the elimination of the drug and increase its concentration in the blood. This can cause adverse effects and toxicity. The nurse should not increase the dose without the prescriber's order and should monitor the patient for signs of overdose or toxicity.

Choice D reason: Decreasing the dose to prevent toxicity is the correct and rational adjustment for a medication that is primarily excreted by the kidneys. The renal impairment can reduce the elimination of the drug and increase its concentration in the blood. This can cause adverse effects and toxicity. The nurse should consult with the prescriber or the pharmacist about the appropriate dose reduction or frequency change for the patient's level of renal function. The nurse should also monitor the patient for the therapeutic response and the adverse effects of the drug.

Choice A reason: Bradycardia is not an adverse effect of diphenhydramine. Diphenhydramine is a medication that blocks the action of histamine, a chemical that causes allergic reactions and inflammation. Diphenhydramine can also block the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Diphenhydramine does not affect the heart rate or blood pressure significantly, and it is not associated with bradycardia, which is a slow heart rate that can cause dizziness, fatigue, or fainting. The nurse should monitor the vital signs of the client after administering diphenhydramine, but bradycardia is not a common or expected outcome.

Choice B reason: Sedation is an adverse effect of diphenhydramine. Diphenhydramine is a medication that blocks the action of histamine, a chemical that causes allergic reactions and inflammation. Diphenhydramine can also block the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Diphenhydramine can cross the bloodbrain barrier and block the histamine receptors in the brain, which are involved in regulating the sleepwake cycle and alertness. Diphenhydramine can cause sedation, sleepiness, drowsiness, dizziness, and impaired coordination, which can affect the performance and safety of the client. The nurse should instruct the client to avoid driving, operating machinery, or performing other tasks that require mental alertness after taking diphenhydramine, and to take the medication at bedtime or as needed for sleep.

Choice C reason: Constipation is not an adverse effect of diphenhydramine. Diphenhydramine is a medication that blocks the action of histamine, a chemical that causes allergic reactions and inflammation. Diphenhydramine can also block the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Diphenhydramine does not affect the gastrointestinal motility or secretion significantly, and it is not associated with constipation, which is a condition of infrequent or difficult bowel movements. The nurse should encourage the client to eat a balanced and highfiber diet, drink plenty of fluids, and exercise regularly to prevent or treat constipation, but diphenhydramine is not a contributing factor.

Choice D reason: Hypertension is not an adverse effect of diphenhydramine. Diphenhydramine is a medication that blocks the action of histamine, a chemical that causes allergic reactions and inflammation. Diphenhydramine can also block the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Diphenhydramine does not affect the blood pressure or the vascular tone significantly, and it is not associated with hypertension, which is a condition of high blood pressure that can cause headaches, chest pain, or stroke. The nurse should monitor the blood pressure of the client after administering diphenhydramine, but hypertension is not a common or expected outcome.