Metformin is the only biguanide approved by the U.S. Food and Drug Administration (FDA). It is sold in the following formulations and brand names:

A biguanide called buformin may be available in some other countries.

In June 2007 the FDA announced it was seeking stronger “black box” warnings on packaging for thiazolidinediones (TZDs) because of concerns about a potential heightened risk of heart problems. Recent studies have produced mixed findings on whether rosiglitazone increases this risk.

An application for Synordia, a combination of metformin and a cholesterol-reducing drug called fenofibrate, was submitted to European regulators in 2006 but withdrawn late that year by the manufacturer, which said it might resubmit an application in the future. If the application is eventually approved, this would be the first time an antidiabetic agent and a cholesterol drug were available in one pill.