A nurse is providing teaching to an adolescent who has type 2 diabetes mellitus and a new prescription for metformin. Which of the following instructions should the nurse include in the teaching?

Choice A rationale Metformin, a biguanide, commonly causes gastrointestinal side effects, but diarrhea, not constipation, is a more frequent occurrence during the initial phase of therapy. This effect is dose-dependent and results from increased intestinal motility and changes in the gut microbiome. Starting with a low dose and titrating slowly helps mitigate these symptoms. Choice B rationale Taking metformin at the same time each day helps maintain a steady therapeutic concentration in the bloodstream. This consistency is crucial for effective glycemic control, as the medication works by decreasing hepatic glucose production and increasing insulin sensitivity. Adherence to a consistent schedule reduces the risk of missed doses and helps prevent fluctuations in blood glucose levels. Choice C rationale Metformin is used as a long-term therapy for managing type 2 diabetes, not for short-term symptom relief. Type 2 diabetes is a chronic condition that requires continuous management to prevent complications. Metformin's effectiveness depends on its consistent presence in the body to regulate glucose metabolism and improve insulin utilization over an extended period. Choice D rationale Metformin is typically taken with meals to minimize gastrointestinal side effects, such as diarrhea and nausea, not before them. Taking the medication with food, especially the evening meal, can improve tolerability. Its absorption is not significantly affected by food, making this a safe and effective strategy for managing patient comfort.