Diabetes Rx May Be Safe for Kidney Patients

Metformin found safe for people who have both diabetes and kidney disease

(RxWiki News) There’s new hope for people who have both diabetes and kidney disease.

A new report found that metformin could be safely prescribed to people with diabetes and mild to moderate forms of kidney disease. The authors of this report recommended that the US Food and Drug Administration (FDA) update its guidelines for metformin use.

Metformin (brand names Glumetza, Fortamet, Riomet and Glucophage) has been in use for two decades to treat people who have type 2 diabetes. For those who also have kidney disease, however, the FDA recommends metformin not be used.

This recommendation was based on the risk of a condition called lactic acidosis. Lactic acidosis can occur after excessive exercise and in people who have kidney disease. It is also a rare side effect of metformin.

"What we found is that there is essentially zero evidence that this is risky," said lead study author Silvio E. Inzucchi, MD, of Yale University in New Haven, CT, in a press release. "The drug could be used safely, so long as kidney function is stable and not severely impaired."

Lactic acidosis occurs when lactic acid builds up in a person’s bloodstream. The kidneys remove metformin from the blood, and in severe kidney disease, the medication may accumulate to the point that it causes lactic acidosis.

The research team studied 818 articles on the subject of metformin and lactic acidosis published between 1950 and June 2014. They excluded some articles, but 65 studies were included in their review.

Dr. Inzucchi’s team found that the rate of lactic acidosis in people who took metformin was essentially the same as in the overall population of people with diabetes.

In patients who have mild to moderate kidney disease, the risk of metformin causing lactic acidosis was very small, Dr. Inzucchi and team said. However, they did not recommend the use of metformin in people with diabetes and severe kidney disease.

These researchers noted that metformin should only be used along with regular lab testing of kidney function. They also noted that the dose may need to be adjusted for some patients.

This recommendation could be very good news for many people with diabetes, Dr. Inzucchi said. Kidney function tends to decline with age.

"They hit a certain age, their kidney function starts to decline, and the first thing most doctors do is to stop metformin," Dr. Inzucchi said. "What invariably happens next is their diabetes goes out of control. Other drugs may be substituted, but they are usually not generic products like metformin, and so more expensive and may also have more side effects."

In the past, doctors have taken patients off metformin and used other less effective or more expensive medications. These researchers noted that it may be becoming more common, however, for specialists to use metformin despite the FDA recommendations.

This study was published online Dec. 24 in JAMA.

Dr. Inzucchi served as a consultant for Merck, Boehringer Ingelheim, Bristol Myers Squibb, Janssen and Novo Nordisk. Study author Clifford J. Bailey, PhD, served as a consultant for and received honoraria and travel expenses from, AstraZeneca/Bristol Myers Squibb, Sanofi and Merck Sharp & Dohme. Study author Darren K. McGuire, MD, received personal fees from Boehringer Ingelheim, Janssen Research and Development LLC, Sanofi Aventis Groupe, Genentech and Merck Sharp & Dohme.

Review Date: 
December 22, 2014