A patient on metformin reports polyuria, polydipsia and weight gain after 6 months of therapy. What is the most appropriate next step?

• A. Stop taking metformin
• B. Increase the dose yourself
• C. Advise the patient to see their GP as the dose may need to be increased
• D. Switch to insulin

Answer: (C)

These symptoms indicate insufficient blood glucose control despite ongoing metformin therapy. Polyuria and polydipsia are classic signs of hyperglycemia, and after six months on treatment it’s important to reassess rather than assume the current dose is fine. The appropriate step is to have the patient see their GP to review glycemic control (often with an HbA1c and renal function tests), and to decide whether the metformin dose should be increased or whether additional therapy is needed. Self-adjusting the dose or stopping metformin without medical input isn’t appropriate, and switching to insulin isn’t the immediate next step without a clinician’s evaluation. Weight gain isn’t a typical goal of metformin and, in this context, further supports the need for medical review to optimize therapy.