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: Vasodilation is not the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can cause vasodilation by inhibiting the muscarinic receptors on the blood vessels, which normally cause vasoconstriction. However, this effect is not significant or consistent, and it does not improve the symptoms of bradycardia, which is a slow heart rate that can cause dizziness, fatigue, or fainting. The nurse should monitor the blood pressure and the peripheral pulses of the patient after administering atropine.

Choice B reason: Bronchodilation is not the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can cause bronchodilation by inhibiting the muscarinic receptors on the bronchial smooth muscle, which normally cause bronchoconstriction. However, this effect is not relevant or beneficial for the patient with symptomatic bradycardia, who does not have any respiratory problems. The nurse should assess the respiratory rate and the breath sounds of the patient after administering atropine.

Choice C reason: Increase in heart rate is the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can increase the heart rate by inhibiting the muscarinic receptors on the sinoatrial node and the atrioventricular node, which normally slow down the heart rate. This effect is desirable and beneficial for the patient with symptomatic bradycardia, who has a slow heart rate that can cause dizziness, fatigue, or fainting. The nurse should monitor the electrocardiogram and the heart rate of the patient after administering atropine.

Choice D reason: Diuresis is not the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can cause diuresis by inhibiting the muscarinic receptors on the bladder, which normally promote urination. However, this effect is not important or helpful for the patient with symptomatic bradycardia, who does not have any urinary problems. The nurse should measure the urine output and the specific gravity of the patient after administering atropine.

Choice A reason: This is incorrect. Distributing the doses evenly throughout the day may increase the risk of daytime sedation and impair the client's ability to perform daily activities. Diphenhydramine is a sedating antihistamine that causes drowsiness and reduces alertness.

Choice B reason: This is correct. Taking most of the daily dose at bedtime may minimize daytime sedation and help the client sleep better at night. Diphenhydramine is often used as a short-term treatment for insomnia.

Choice C reason: This is incorrect. Taking the medication with meals does not affect the sedative effect of diphenhydramine. It may only reduce the risk of stomach upset, which is not a common side effect of diphenhydramine.

Choice D reason: This is incorrect. Gradually decreasing the dose once tolerance to the effect is reached may not be advisable, as it may reduce the effectiveness of the medication for relieving pruritus. Diphenhydramine is an antihistamine that blocks the action of histamine, a chemical that causes itching and inflammation in allergic reactions.