Which statement about metformin is untrue?

The statement that metformin is typically used in conjunction with other diabetes medications is untrue because metformin can be effective as a monotherapy for managing type 2 diabetes. It is often the first-line treatment recommended for patients with this condition due to its ability to lower blood glucose levels effectively and improve insulin sensitivity. While some patients may indeed require additional medications to achieve their glucose targets, it is not universally necessary to use metformin in combination with other antidiabetic agents right from the start. This versatility of metformin allows it to be used alone initially, and only additional medications are added later if further glycemic control is needed.

The other choices reflect accurate information regarding metformin. It does work by decreasing hepatic glucose production, which is key to its mechanism of action in reducing blood sugar levels. There is a recognized risk of lactic acidosis, particularly in certain populations, such as those with renal impairment, who may be unable to clear metformin effectively. Furthermore, the recommendation against use in those with significant renal impairment is grounded in safety concerns, as impaired renal function can elevate the risk of lactic acidosis, making the other statements true.