Final answer:
The recommended oral antidiabetic agent as monotherapy for a newly diagnosed diabetic client with a glycated hemoglobin (HbA1c) of 7.5 is metformin (Glucophage).
Step-by-step explanation:
A client with a newly diagnosed diabetes with a glycated hemoglobin (HbA1c) of 7.5 who is started on therapeutic lifestyle changes (TLCs) and medical nutrition therapy (MNT) is often recommended metformin (Glucophage) as the first choice for monotherapy. Metformin is usually preferred due to its effectiveness in lowering blood glucose levels, favorable effects on weight, and a lower risk of causing hypoglycemia. It also has cardiovascular benefits which are important for diabetic patients.