The Medical Letter on Drugs and Therapeutics
In Brief: New Recommendations for Use of Metformin in Renal Impairment
Download PDF:   US English
Med Lett Drugs Ther. 2016 Apr 25;58(1493):51
 Select a term to see related articles  drug safety   Glucophage   metformin   type 2 diabetes 

The FDA has required labeling changes that replace serum creatinine (SCr) with estimated glomerular filtration rate (eGFR) as the parameter used to determine the appropriateness of treatment with the biguanide metformin (Glucophage, and others) in patients with renal impairment. These changes will allow more patients with mild to moderate renal impairment to receive metformin, which is generally the first drug prescribed for treatment of type 2 diabetes.

Metformin was previously contraindicated in women with a SCr level ≥1.4 mg/dL and in men with a SCr level ≥1.5 mg/dL, but use of SCr as a surrogate indicator tends to underestimate renal function in certain populations (e.g., younger patients, men, black patients, patients with greater muscle mass). The calculation of eGFR takes into account age, race, and sex, as well as SCr level, providing a more accurate assessment of kidney function. A literature review summarized in an FDA Drug Safety Communication concluded that, based on eGFR, metformin is safe to use in patients with mild renal impairment and in some patients with moderate renal impairment.1

The eGFR should be calculated before patients begin treatment with metformin and at least annually thereafter. Metformin is now contraindicated in patients with an eGFR <30 mL/min/1.73 m2, and starting treatment with the drug in patients with an eGFR between 30 and 45 mL/min/1.73 m2 is not recommended. If the eGFR falls below 45 mL/min/1.73 m2 in a patient already taking metformin, the benefits and risks of continuing treatment should be assessed. Metformin should be not be administered for 48 hours after an iodinated contrast imaging procedure in patients with an eGFR <60 mL/min/1.73 m2 or a history of liver disease, alcoholism, or heart failure, or in those receiving intra-arterial contrast, and the eGFR should be re-evaluated before treatment is restarted.

© The Medical Letter, Inc. All Rights Reserved.
The Medical Letter, Inc. does not warrant that all the material in this publication is accurate and complete in every respect. The Medical Letter, Inc. and its editors shall not be held responsible for any damage resulting from any error, inaccuracy, or omission.
This article has been freely provided.
arrow to previous article
arrow to next article