Which adverse effect is commonly associated with metformin?

• A. GI upset
• B. Hypoglycemia
• C. Hyperkalemia
• D. Weight gain

Answer: (A)

Gastrointestinal upset is the most common adverse effect seen with metformin. Nausea, abdominal discomfort, bloating, and diarrhea frequently appear, especially when starting therapy or when doses are high. These effects are usually dose-related and tend to improve over time or with slower titration. Taking metformin with meals and using an extended-release formulation can help minimize these symptoms.

Hypoglycemia is not typical with metformin alone because it does not increase insulin secretion; however, the risk rises when metformin is used in combination with other glucose-lowering agents. Hyperkalemia is not a characteristic adverse effect of metformin. Weight gain is not expected; metformin more commonly causes weight stability or even modest weight loss in some patients.