Alcohol can interact with some medicines, including those you can buy over the counter. Some of these interactions can be harmful or stop your medicine from working properly, so it’s important to know when it isn’t safe to mix the two.
How are medicines and alcohol metabolised?
Your liver breaks down much of the food, drinks, medicines and alcohol that enters your body. It does this through chemical reactions in the cells.
Chemical reactions in cells often need other chemicals called enzymes to speed them along. The cell uses particular enzymes to help them break down particular substances.
In some cases, both medicines and alcohol use the same enzymes. The medicines and alcohol interfere with each other, with the result that some medicines can be made less effective, and some can become toxic.
There’s also the risk that alcohol enhances the side effects of some medicines and make them worse.
Problems from alcohol interacting with medicines
Problems can happen with many different medicines. The most common ones are antibiotics, antidepressants, painkillers, sleeping tablets and certain antihistamines used in cough and cold remedies as well as some travel and allergy medicines.
If you take the wrong medicine with alcohol, you can get:
- nausea and vomiting
- drowsiness or sleepiness
- dizziness and fainting
- blood pressure changes
- uncharacteristic behaviour
- poor or loss of coordination
It can take time for your body to metabolise alcohol and medicines, so you can have these symptoms even if you don’t take the medicine at exactly the same time as consuming alcohol.
There is a risk of serious complications such as:
Who is at greatest risk?
Women, older people and those with liver problems are at greatest risk. You are also at greater risk of you:
- drink a lot of alcohol
- are small
- aren’t healthy.
Safe use of medicines and alcohol
Always read the label of your medicine. If it carries a warning, avoid alcohol. It’s also best to seek doctor’s or pharmacist’s advice if you are unsure, and before you take any new medicine, including complementary (sometimes called natural or herbal) medicines.
Last reviewed: May 2016