Alcohol and medicines and why you should ask before drinking

Why alcohol and medicines clash

Alcohol and many medicines are handled by the same organ: the liver. Both also act on the brain and the nervous system. That overlap is where the trouble starts. Alcohol can make a medicine stronger, weaker or harder on the body. A medicine can make alcohol hit far harder than usual.

The amount of alcohol does not need to be large. A single 650 ml bottle of 5% beer carries about 32 ml of pure alcohol, roughly two and a half small pegs of whisky. For some medicines, that is plenty to cause a problem.

Medicines that cause a reaction with any alcohol

A small number of medicines react badly with even a little alcohol. The best known is metronidazole, an antibiotic often prescribed for stomach and dental infections. Alcohol taken with it can cause flushing, nausea, vomiting, headache and a racing heart. Patient leaflets usually advise avoiding alcohol during the course and for at least 48 hours after the last dose.

Disulfiram, a medicine used to support people who are stopping drinking, works on the same principle on purpose. If you are prescribed any medicine with this kind of warning, take it seriously. Alcohol free beer can contain up to about 0.5% ABV, so ask whether that is acceptable too.

Medicines that add to drowsiness

A much larger group of medicines makes you drowsy. Alcohol makes that worse. The combination slows reactions and can, in high amounts, slow breathing. Common examples include:

• Sleeping tablets and anxiety medicines such as benzodiazepines.
• Strong painkillers, including opioids such as tramadol and codeine.
• Older antihistamines used for allergies and colds, the kind labelled "may cause drowsiness".
• Some antidepressants and medicines for seizures or nerve pain.

Cough and cold remedies bought over the counter can contain sedating ingredients too. Read the label even for something you buy without a prescription.

Medicines alcohol quietly interferes with

Some interactions do not announce themselves. They change how a medicine works in the background:

• Blood thinners such as warfarin can be affected by alcohol, changing how well blood clots.
• Diabetes medicines, including insulin and some tablets, combined with alcohol can lead to low blood sugar, sometimes hours later.
• Blood pressure medicines plus alcohol can cause dizziness or fainting, especially when standing up.
• Paracetamol is processed by the liver. Regular heavy drinking with paracetamol puts extra strain on it.

None of this means you can never drink while on these medicines. It means the answer depends on your medicine, your dose and your health, which only a doctor or pharmacist can judge.

The questions to ask

Pharmacists answer this question every day and will not judge you for asking. Be specific:

• "Can I drink alcohol while taking this? How much, if any?"
• "How long after the last dose should I wait?"
• "Is alcohol free beer all right?"
• "Will this make me drowsy enough that I should not drive even without alcohol?"

Tell them what you usually drink. "Two pints of 6% IPA on a Saturday" is far more useful than "I drink socially". Our guide to standard drinks helps you put a number on it.

Food and timing do not cancel an interaction

Some people try to manage the risk by eating first or spacing tablets and drinks apart. Food does slow how fast alcohol is absorbed, as our guide to eating before drinking explains. It does not stop an interaction. Neither does taking the tablet in the morning and drinking at night, for medicines that stay in the body for a day or more.

If you are on a short course, the simplest answer is often to skip beer until the course is over. A good beer will still be there in a week.

Herbal and traditional remedies deserve the same question. Many people in India take ayurvedic or home remedies alongside prescribed medicine and never mention them. Tell your pharmacist about everything you take, not only the tablets from the doctor, so the advice covers the full picture.

Check your current prescriptions today

Take out any medicines you are taking now and read the alcohol line on each leaflet or label. If anything is unclear, ask your pharmacist the next time you visit. If you are planning a tasting or a festival while on a course of tablets, ask before the date, not on the day.

Common questions

Can I drink beer while taking antibiotics?

It depends on the antibiotic. Some, such as metronidazole, react badly with any alcohol. Ask your pharmacist or doctor about your specific medicine.

Is alcohol free beer safe with medicines?

Alcohol free beer can contain up to about 0.5% ABV. For most medicines that is not a concern, but for some it may be. Ask your pharmacist.

Why do medicines say avoid alcohol?

Alcohol can make some medicines stronger or weaker, add to drowsiness or cause a direct reaction. The liver handles both.

Who should I ask about alcohol and my medicine?

Your pharmacist or the doctor who prescribed it. Tell them what and how much you usually drink.