A client presents with auditory hallucinations. Which medication has an adverse effect profile that includes this presenting symptom?

Choice A reason: Metformin is a biguanide used primarily for the management of type 2 diabetes mellitus. Its common side effects are gastrointestinal, such as nausea and diarrhea, and it can cause vitamin B12 deficiency over long-term use. It does not have a known association with causing psychiatric symptoms like auditory hallucinations. Choice B reason: Amiodarone is an antiarrhythmic medication with a broad side effect profile affecting the thyroid, lungs, and liver. While it can cause neurological side effects like tremors, ataxia, or peripheral neuropathy, it is not a common pharmacological cause of acute psychosis or auditory hallucinations in standard clinical practice. Choice C reason: Vitamin B12 is an essential nutrient. Supplementation is used to treat deficiency, which itself can cause psychiatric symptoms (megaloblastic madness). However, the medication (supplement) itself does not have an adverse effect profile that includes auditory hallucinations; rather, it is the treatment for neurological and psychiatric symptoms caused by its absence. Choice D reason: Prednisone, a potent corticosteroid, is well-documented to cause "steroid-induced psychosis." This can manifest as mood disturbances, mania, depression, or overt psychotic symptoms, including auditory and visual hallucinations. The risk is dose-dependent, and symptoms typically resolve upon the tapering or discontinuation of the corticosteroid therapy.