A nurse is providing teaching to a client about proper administration of a medication regarding meals.
The nurse should instruct the client that the presence of food will alter the rate of which of the following pharmacokinetic processes?

Choice A rationale

Gingival hyperplasia is an overgrowth of gum tissue, often associated with certain medications like phenytoin or cyclosporine. It is caused by an increase in the number of fibroblasts and collagen deposition in the gingiva. Haloperidol, an antipsychotic, primarily affects dopamine receptors in the brain and does not cause gingival hyperplasia.

Choice B rationale

Haloperidol is a first-generation antipsychotic that blocks D2 dopamine receptors in the brain. This blockade, particularly in the nigrostriatal pathway, can lead to extrapyramidal symptoms (EPS) such as acute dystonia, parkinsonism (including muscle rigidity, bradykinesia, and tremor), and akathisia. Muscle rigidity is a common manifestation of drug-induced parkinsonism.

Choice C rationale

Polyuria is the excessive production of urine, often a symptom of diabetes mellitus or insipidus. It results from impaired water reabsorption in the kidneys. While some medications can affect fluid balance, haloperidol's primary pharmacological action on dopamine receptors does not directly induce polyuria as a typical adverse effect.

Choice D rationale

Bruising, or ecchymosis, results from bleeding under the skin, often due to trauma or coagulation disorders. It is caused by extravasation of blood from capillaries into surrounding tissues. Haloperidol does not affect coagulation factors or platelet function and is not associated with increased bruising as a direct adverse effect.

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.