Metformin can be used safely in patients with mild impairment in kidney function and in some patients with moderate impairment in kidney function, according to the FDA’s recent review of several medical studies.

These findings have prompted the FDA to require manufacturers to change the labeling for metformin-containing drugs. These drugs’ labels now must include the results of the medical studies and new measures of kidney function for determining if a patient can use metformin, says a written statement from the FDA.

Metformin’s current labeling strongly recommends against its use in some patients with kidneys that do not work normally. The FDA is specifically requiring that new labels include the recommendation that the measure of kidney function used to determine whether a patient can receive metformin be changed from one based on a single laboratory parameter (blood creatinine concentration) to one that provides a better estimate of renal function (that is, the glomerular filtration rate estimating equation, eGFR ).

The full labeling recommendations are available in the FDA’s written statement.

Additional information including a data summary and a list of metformin-containing drugs is available in the FDA Drug Safety Communication .

The FDA asks that healthcare professionals and patients report adverse events or side effects related to the use of metformin-containing drugs to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program .