Final answer:
The correct instruction for taking acarbose, a medication for type 2 diabetes mellitus, is to take it with the first bite of each regular meal to help control blood sugar levels effectively.
Step-by-step explanation:
The correct instruction for a client with type 2 diabetes mellitus who has been prescribed acarbose is to take the medication with the first bite of each regular meal. Acarbose works by slowing down the digestion of carbohydrates, which helps to prevent spikes in blood sugar levels after meals. It is important to take it at mealtime for it to work effectively. Taking it at bedtime would not provide the necessary benefit tied to meal intake, and acarbose does not treat hypoglycemia but rather helps to prevent hyperglycemia. While headache and dizziness can be side effects of many medications, they are not the most common side effects associated with acarbose. Common side effects of acarbose may include gastrointestinal symptoms such as flatulence, diarrhea, and abdominal pain.