The findings of a new study raises potential concerns about the side effects of meformin, suggesting that the popular diabetes drug may impair brain functions and cause users to experience problems thinking.
Metformin is a widely used medication for treatment of type 2 diabetes, which is also known under the brand names Glumetza, Riomet, Fortamet and Glucophage. It is also part of several popular combination therapies, including the blockbuster medication Janumet, which combines metformin with the top selling diabetes drug Januvia.
In a report published by the journal Diabetes Care, researchers compiled data from several different studies, including the Primary Research in Memory (PRIME) study; Australian Imaging, Biomarkers and Lifestyle (AIBL) study and data from the Barwon region of southeastern Australia.
Researchers found that participants with diabetes performed worse on cognitive performance than those who did not have diabetes, with individuals taking a metformin drug performing significantly worse.
More than 1,300 patients were evaluated who had Alzheimer’s disease, mildly impaired brain function and no cognitive impairments; along with a subset group which also had type 2 diabetes or impaired glucose intolerance. Patients who suffered a stroke or had neurodegenerative diseases other than Alzheimer’s were not included in the study.
Patients with type 2 diabetes performed poorly on cognitive impairment tests and those who took metformin performed even worse.
Researchers found metformin was associated with a vitamin B12 deficiency, which in turn resulted in impaired cognitive performance. Patients with vitamin B12 levels less than 250 pmol/L had the worst cognitive performance.
Conversely, patients with type 2 diabetes taking metformin, but who also took calcium or vitamin B12 supplements had better cognitive outcomes.
Eileen Moore, PhD, and her team of researchers from the University of Melbourne in Australia used a mini-mental state exam (MMSE) to determine cognitive performance in patients. The average patients age was 73 years old, with approximately 60% being female.
Metformin has been hailed by some as a wonder drug in treating type 2 diabetes, however not with its own set of risks. Prior studies have suggested the drug could increase the risk of heart disease and cancer. It has also been associated with vitamin B12 deficiency.
Researchers say the data warrants further trials to investigate the association between diabetes, cognitive decline and metformin. They also would like to assess the effects of vitamin B12 and calcium on cognition in the older population who have diabetes and are taking drugs like Glucophage or Glumetza.