A nurse is caring for a client who is taking lovastatin and has a new prescription for ezetimibe to lower cholesterol levels.
Which of the following laboratory values should the nurse monitor?

Choice A rationale

A history of migraine headaches is not a contraindication for metformin. Metformin's primary mechanism involves reducing hepatic glucose production and improving insulin sensitivity in peripheral tissues. Migraine headaches are neurological conditions not directly influenced by or interacting adversely with metformin's metabolic actions.

Choice B rationale

Alcohol use disorder is a significant contraindication for metformin due to an increased risk of lactic acidosis. Alcohol consumption can impair hepatic lactate metabolism and increase lactate production, while metformin itself can elevate lactate levels. The combination markedly raises the likelihood of this severe metabolic complication.

Choice C rationale

A history of peptic ulcer disease is not a direct contraindication for metformin. While some gastrointestinal side effects like nausea or diarrhea can occur with metformin, these are generally not severe enough to preclude its use in patients with a history of peptic ulcer disease, especially if the ulcer is currently resolved.

Choice D rationale

Tobacco use is not a direct contraindication for metformin. While tobacco use is a risk factor for various health issues, including cardiovascular disease and complications of diabetes, it does not physiologically interact with metformin in a manner that would contraindicate its use. The primary concerns with tobacco are unrelated to metformin's metabolism or side effect profile.

Choice A rationale

Administering half the dose now and the other half in 30 minutes is an inappropriate action for a beta-blocker like atenolol when the heart rate is already low. This approach would still lead to a further reduction in heart rate, potentially causing symptomatic bradycardia or other adverse cardiovascular events, and is not a standard medication administration protocol.

Choice B rationale

Atenolol is a beta-blocker that reduces heart rate and blood pressure. A normal apical heart rate typically ranges from 60 to 100 beats/min. A heart rate of 61/min, although within the normal range, is on the lower end, especially for a client receiving a beta-blocker. Administering atenolol could further decrease the heart rate, leading to symptomatic bradycardia or other adverse effects. Therefore, withholding the medication and contacting the provider is the safest action to assess the client's tolerance and determine if a dose adjustment is necessary.

Choice C rationale

Administering the prescribed dose when the client's apical heart rate is 61/min is generally contraindicated for a beta-blocker like atenolol. Beta-blockers work by decreasing heart rate. Giving the medication could cause the heart rate to fall below acceptable limits (e.g., less than 60 beats/min), potentially leading to dizziness, syncope, or cardiac arrest, necessitating careful clinical judgment.

Choice D rationale

Atropine is an anticholinergic medication used to treat bradycardia (heart rate less than 60 beats/min) by blocking the action of acetylcholine on muscarinic receptors, thereby increasing heart rate. While atropine can be used to treat symptomatic bradycardia, preparing to administer it *before* giving atenolol, especially when the heart rate is 61/min and the client is not yet bradycardic, is premature and not indicated.