Metformin is a commonly prescribed medication for individuals managing type 2 diabetes. It controls blood sugar by reducing glucose production in the liver, decreasing glucose absorption from food, and enhancing the body’s response to insulin. Combining metformin with alcohol can lead to serious complications.
Lactic Acidosis and Metformin
Combining metformin and alcohol increases the risk of lactic acidosis, a rare but severe medical condition. This occurs when excessive lactic acid builds up in the blood, leading to a dangerous pH imbalance. Metformin itself can slightly increase lactate levels, but alcohol significantly exacerbates this risk by interfering with the liver’s ability to clear lactate from the bloodstream.
The liver metabolizes both alcohol and lactate. When alcohol is consumed, the liver prioritizes processing it, which can inhibit pathways necessary for lactate metabolism. This dual effect—metformin increasing lactate production and alcohol hindering its removal—can lead to a rapid and dangerous accumulation of lactic acid.
Symptoms of lactic acidosis can progress quickly and include muscle pain, weakness, difficulty breathing, abdominal pain, nausea, vomiting, dizziness, lightheadedness, and a fast or slow heart rate. Feeling cold or unusual sleepiness are also possible signs. Immediate medical attention is necessary if these symptoms appear.
Hypoglycemia and Blood Sugar Management
Combining metformin with alcohol also presents a substantial risk of hypoglycemia, or dangerously low blood sugar. Metformin lowers blood sugar by reducing liver glucose production and increasing insulin sensitivity. Alcohol, independently, can also cause blood sugar levels to drop. The liver plays a central role in maintaining stable blood glucose levels by storing and releasing glucose as needed. When alcohol is present, the liver prioritizes its detoxification, which can impair its ability to release stored glucose, a process known as gluconeogenesis.
This interference with the liver’s glucose production, coupled with metformin’s blood-sugar-lowering actions, can result in a sudden drop in blood sugar. Symptoms of hypoglycemia include dizziness, confusion, sweating, shakiness, a rapid heartbeat, blurred vision, headaches, and irritability. In severe cases, it can lead to loss of consciousness, seizures, or even be fatal if not promptly treated.
Factors Increasing Risk and Safe Practices
Several factors can increase an individual’s risk when combining metformin and alcohol. People with pre-existing conditions affecting the kidneys or liver are at higher risk because these organs are crucial for metabolizing both metformin and alcohol. Impaired kidney function can lead to a buildup of metformin in the body, intensifying its effects. Liver dysfunction can hinder the processing of alcohol and the clearance of lactate, further increasing the risk of both lactic acidosis and hypoglycemia.
Excessive alcohol consumption, particularly binge drinking, elevates these risks. Binge drinking involves consuming a large amount of alcohol in a short period, overwhelming the body’s metabolic capacities. Advanced age (over 65) and dehydration also contribute to increased susceptibility. Drinking alcohol on an empty stomach further increases the risk of hypoglycemia, as there is no food to buffer the blood sugar response.
Individuals taking metformin should consult a healthcare professional about alcohol consumption. While some may tolerate small amounts, complete avoidance is often recommended, especially for those with existing risk factors. If alcohol is consumed, it should be done in moderation (one drink per day for women and up to two for men), and always with food. Seek immediate medical attention for severe symptoms like weakness, confusion, or difficulty breathing, and carry medical identification indicating diabetes.