Grace asked
Are there any interactions between Metformin and alcohol that might cause memory loss while drinking? Lately, I barely have to drink anything (2 or 3 beers) and my memory of the time is significantly impaired.
I recently stopped taking Topiramate for migraines, but began taking Metformin to manage my PCOS symptoms. I've looked up information but the only harmful interactions I could find were lactic acidosis and low blood sugar.
Answer
It is recommended to either limit or avoid drinking alcohol while taking the diabetes medication metformin.
As you mentioned in your question, metformin raises the risk of a condition known as lactic acidosis. Lactic acidosis is the accumulation of lactate in the blood, which lowers the pH (i.e.increases the acidity) of the bloodstream. Left untreated, it is a potentially fatal condition. Blood lactate concentrations are known increase when combining alcohol with metformin.
At onset, the symptoms of lactic acidosis are often subtle, accompanied mostly by nonspecific symptoms such as fatigue and muscle pain. These can quickly be followed by more serious symptoms such as respiratory distress. Lactic acidosis is a medical emergency which must be treated immediately.
In addition, metformin is well known to cause nausea and GI distress. Mixing alcohol with metformin can potentiate these adverse reactions leading to extreme nausea, vomiting and diarrhea.
In regards to memory loss when mixing alcohol with metformin, there is no data regarding that specific interaction. Having said that, metformin has conflicting information in regard to how it may affect memory by itself.
Early studies with metformin actually showed potential promise for treating or lowering the risk of neurological conditions such as Alzheimers disease. Most of these studies are theoretical however and were completed 'in vitro', meaning in a lab outside of any biological context.
More recent studies have found a more definitive link between metformin and cognitive decline. In fact, some studies have shown that impaired memory or cognition may be twice as likely in diabetics taking metformin versus patients that do not.
It has been theorized that this cognitive decline may be due metformin lowering Vitamin B12 levels in the body. Multiple studies have shown that metformin does in fact lower B-12 levels up to 30%. You may find some benefit is having your blood B12 levels checked as well as taking a Vitamin B12 supplement. In fact, many doctors recommend having your Vitamin B12 levels checked yearly.
Preliminary studies such as this one shows that Vitamin B12 supplementation may be beneficial to combat the cognitive decline associated with metformin.
