Has anyone heard of brain fog or confusion after taking Metformin for diabetes?

A fellow caregiver asked...

Has anyone heard of brain fog or confusion after taking Metformin? My mother was without her Metformin for two days and I am not sure if it was a coincidence or not, but it seemed as if she was a little less confused on those two days. She takes Razadyne and Namenda for her Alzheimer's.

Expert Answer

Theresa Garnero is clinical nurse manager of Diabetes Services at California Pacific Medical Center in San Francisco.

No patients I have worked with have reported experiencing "brain fog" or confusion as a result of taking Metformin. Usually, the main side effect is gas, bloating and diarrhea when first starting the medication.

That said, medications have many idiosynchratic (unexpected) reactions. It's hard to tell with your mother's Alzheimer's condition. Since you noted an improvement in her mentation when she was NOT taking Metformin, it's best to let her doctor know so other options may be considered.