It is generally acceptable to drink a glass of wine while taking metformin; however, it's best to be careful because of the risk of lactic acidosis. Additionally, there is a risk of hypoglycemia when a diabetes patient drinks alcohol, whether or not the patient takes metformin. Symptoms of hypoglycemia include hunger, shakiness, nervousness, sweating, dizziness, sleepiness, confusion, difficulty speaking, anxiety and weakness. Symptoms of lactic acidosis include nausea, vomiting, hyperventilation, abdominal pain, lethargy, anxiety, hypotension, rapid or irregular heart rate and metal status changes. If you take metformin or are diabetic, ask your doctor if it's safe to drink alcoholic beverages.
Metformin is a biguanide, a type of oral medication used to treat Type 2 diabetes by helping control the amount of glucose in the blood. It primarily works to reduce gluconeogenesis, glucose production by the liver, but also aids in blood glucose control by increasing insulin sensitivity and decreasing glucose absorption in the gastrointestinal tract. The most common side effects of metformin are gastrointestinal related, but rarely, lactic acidosis can occur. Hypoglycemia is an unlikely side effect of metformin when it is used alone.
The liver is largely responsible for clearing lactate from the body, and when a patient takes metformin, the rate of clearance by the liver is reduced. This is part of the reason for the correlation between taking metformin and the risk of lactic acidosis. Dr. Thomas Higgins, an endocrinologist at Boulder Medical Center, cautions against prescribing metformin to patients with conditions that predispose them to lactic acid accumulation. For example, use of metformin, which is not metabolized but cleared via tubular secretion into the urine, is cautioned against in the presence of kidney impairment. When a patient with impaired kidney function takes metformin, clearance of metformin and lactate is reduced, and can lead to lactic acidosis.
Alcohol and Wine
According to the Centers for Disease Control and Prevention, a standard glass of wine is 5 oz. in volume and contains 3.7 g of alcohol. Patients taking metformin need not necessarily avoid alcohol. But depending upon the patient’s medical history, which may include conditions that increase lactic acid production, avoidance of alcohol is prudent. Additionally, larger amounts of alcohol -- more than a glass of wine, for example -- are not recommended.
Alcohol and Hypoglycemia
According to the National Institute of Diabetes and Digestive and Kidney Diseases, drinking alcoholic beverages can cause hypoglycemia. This is especially true when the beverage is consumed on an empty stomach, or if excessive amounts are consumed. The liver is the primary site of alcohol metabolism, thus, processing the alcohol can interfere with the liver’s efforts to raise blood glucose. Further, the more alcohol consumed, the more time it will take for the liver to metabolize and clear it from the system.