Is It Safe to Mix Metformin and Alcohol?

Medically reviewed by Alan Carter, PharmD on April 26, 2016Written by University of Illinois-Chicago, Drug Information Group on April 26, 2016

Overview

If you’re taking metformin to treat your diabetes, you may be wondering how this drug affects your ability to drink safely. Drinking alcohol can affect your diabetes symptoms directly, but there are additional risks if you drink alcohol with metformin. This article gives you information on how alcohol interacts with metformin and also how drinking alcohol can affect your diabetes.

Alcohol and metformin

With any medicine you take, you should be aware of interactions that can happen if you use other substances. Metformin and alcohol can interact to increase your risk of harmful effects. You are at much greater risk of these effects if you frequently drink a lot of alcohol or you binge drink (drink a lot in short periods). These effects include an extremely low blood sugar level, called hypoglycemia, and a condition called lactic acidosis.

Hypoglycemia

Drinking alcohol while you’re taking metformin may cause extremely low blood sugar levels. Some symptoms of low blood sugar levels can be similar to symptoms of having too much alcohol. These include:

  • drowsiness
  • dizziness
  • confusion

Tell the people who are with you while you drink that you have diabetes. They can help you watch for these symptoms. If you or the people around you notice these symptoms, stop drinking and eat something right away to help increase your blood sugar level. If your symptoms of hypoglycemia are severe, such as losing consciousness, and you do not have a glucagon hypoglycemia rescue kit, someone with you should call 9-1-1.

A glucagon hypoglycemia rescue kit includes human glucagon (a natural substance that helps balance your blood sugar level), a syringe to inject it, and instructions. You can use this kit for severe hypoglycemia when eating food will not help. If you are not familiar with this kit, talk to your doctor about whether you should get one.

Lactic acidosis

Lactic acidosis is rare, but it is a serious side effect. It’s caused by a buildup of lactic acid in your blood. Lactic acid is a chemical that is naturally produced by your body as it uses energy. When you take metformin, your body produces more lactic acid than it usually does. When you drink alcohol, your body can’t get rid of lactic acid as quickly. Drinking too much alcohol, especially with metformin, can cause a buildup of lactic acid. This buildup can cause serious damage to your kidneys, lungs, heart, and blood vessels. If lactic acidosis is not treated right away, it can cause these organs to shut down, which can lead to death. Symptoms of lactic acidosis include:

  • weakness
  • tiredness
  • dizziness
  • lightheadedness
  • unusual muscle pain, such as sudden and severe pain in muscles that don’t usually cramp
  • trouble breathing
  • stomach discomfort, such as a fluttering feeling, nausea, cramping, or sharp pains
  • feeling cold

Lactic acidosis is a medical emergency that must be treated in a hospital. If you take metformin and have been drinking and you notice these symptoms, call your doctor right away or go to the nearest hospital’s emergency room.

Alcohol and diabetes

In addition to interacting with metformin, alcohol can also affect your diabetes directly by lowering your blood sugar levels. Alcohol can cause low blood sugar levels for up to 24 hours after you drink it.

Most people with diabetes can have moderate amounts of alcohol. If you’re a woman, a moderate amount means no more than one drink per day. If you’re a man, it means no more than two drinks per day. You should also take the following precautions if you drink and have diabetes:

  • Don’t drink alcohol on an empty stomach.
  • Don’t drink alcohol when your blood sugar is low.
  • Eat food before or after drinking alcohol.
  • Stay hydrated by drinking plenty of water while drinking alcohol.

Check your blood sugar levels before you drink, while you drink, and for 24 hours after you drink alcohol. If your blood sugar is too low, eat something to increase your blood sugar to a safe level.

What is metformin?

Metformin is used to treat type 2 diabetes. People with type 2 diabetes have a problem with a substance called insulin. Insulin typically helps your body control the levels of glucose (sugar) in your blood. However, if you have type 2 diabetes, your insulin can’t control your blood sugar level like it should, so your blood sugar level gets too high. This can happen because of one or both of the following reasons:

  • Your body doesn’t make enough insulin to help your body use sugar.
  • Your body doesn’t respond like it should to the insulin it does make.

Metformin helps control your blood sugar levels by addressing both of these problems. Metformin helps reduce the amount of sugar that your liver releases into your blood. It also helps your body respond to your insulin better so that it uses more of the sugar in your blood. Using the sugar helps decrease the amount of sugar that stays in your blood.

Read more: Detailed drug information for metformin, including dosage, side effects, interactions, and more »

Ask your doctor

Alcohol and metformin can interact. However, taking metformin does not necessarily mean that you can’t drink alcohol. Alcohol affects people differently, so ask your doctor if it’s safe for you. Only your doctor knows your medical history well enough to know how alcohol could affect you while you take metformin. If your doctor does tell you that it’s safe for you to drink alcohol, remember that moderation is the key.

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