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Monday’s medical myth: you can’t mix antibiotics with alcohol

Staying off alcohol when taking antibiotics has been hallowed advice from GPs, pharmacists and well-meaning relatives for decades. It’s difficult to work out exactly where the advice orginated, but Karl…

Few antibiotics preclude drinking alcohol but it’s a bad idea to get drunk when you have an infection. DeusXFlorida

Staying off alcohol when taking antibiotics has been hallowed advice from GPs, pharmacists and well-meaning relatives for decades.

It’s difficult to work out exactly where the advice orginated, but Karl Kruszelnicki (Dr Karl) suggests it dates back as far back as the 1950s, when penicillin came into use as the first really effective treatment for sexually transmitted infections (STIs) such as gonorrhoea and syphilis.

Doctors were apparently worried that disinhibited acts under the influence of the demon drink could undo their expensive treatment with the new miracle drugs. So patients were advised to abstain (from alcohol) until things cleared up.

A recent survey suggests these fears may be well founded. Participants receiving treatment for STIs at a United Kingdom clinic were more likely to engage in risky sexual activity while intoxicated.

Some antibiotics react badly to alcohol. Brandice Schnabel

The advice that you shouldn’t drink alcohol while taking antibiotics does hold true for a small group of anti-infective drugs including metronidazole (Flagyl, Metronide or Metrogyl), tinidazole (Fasigyn or Simplotan) and sulfamethoxazole/trimethoprim (Bactrim, Co-trimoxazole). These drugs block one of the major pathways that metabolise alcohol and cause a rapid build up of nasties called acetaldehydes, which are responsible for many of the unpleasant physical effects of hangovers. With these drugs on board, you can be red-faced, fainting and vomiting after as little as one glass of beer.

But these anti-infective drugs have fairly specialised uses – to treat infections with organisms such as giardia (from contaminated drinking water) or intestinal worms, for instance – and it would be unusual to be prescribed these drugs without a long lecture from your doctor or pharmacist about the potential adverse reaction.

For nearly all other types of antibiotics there is no clear evidence of harm from modest alcohol intake. A comprehensive but readable summary of alcohol and medication interference can be found here.

But this doesn’t mean it’s a good idea to drink to excess when you’re in the grip of an infection, as the sedative and nauseating effects of the alcohol are likely to increase if you are unwell.

Alcohol-induced dilation of blood vessels in the limbs interferes with your body’s attempts to raise a fever to slow the spread of infection. Your kidneys will be forced by the alcohol to lose more fluid, thus increasing the risk of dehydration. And the deep, aching muscle pain produced by viral infections may be more likely to lead to serious muscle damage when combined with binge drinking.

Alcohol can exacerbate mild or moderate infections, even if you’re not on antibiotics. schipulites

Some antibiotics such as isoniazid and flucloxacillin (Flopen, Staphylex) may inflame the liver (causing mild hepatitis) in a small percentage of those treated. A boozy night out could further irritate the liver, which is already working hard to get rid of the extra alcohol. A similar mild hepatitis may occur with some infections such as glandular fever, which would have the same outcome.

So if you’re unwell and thinking of having a big one at the office end-of-year party, it’s better to go easy on the alcohol whether you are on antibiotics or not. You’ll recover quicker and you’ll reduce your risk of secondary complications.

If you’re on one of the problematic drugs, it’s important to take the “no alcohol” warning seriously or you’ll quickly and deeply regret even a few mouthfuls of alcohol.

For most antibiotic users, though, a glass of bubbly or a cold beer at your office Christmas party should be fine.

Join the conversation

12 Comments sorted by

  1. Tim Scanlon

    Author and Scientist

    Now this was a new one for me. Thanks!

  2. jerry sprom

    logged in via email

    If you are crook enough to require antibiotics, why would you want to drink alcohol anyway?

    1. Tim Scanlon

      Author and Scientist

      In reply to jerry sprom

      My wife was just prescribed antibiotics for a bruised toe "in case it became infected".

      I'm quite sure that there are plenty of minor ailments being treated. You'd need to drink to repress the knowledge that you are helping to breed a superbug.

    2. Michael Vagg

      Clinical Senior Lecturer at Deakin University School of Medicine & Pain Specialist at Barwon Health

      In reply to Tim Scanlon

      That's a good point Tim! We could encourage conviviality in the name of preventing antibiotic resistance...

  3. Lucien Beauley

    retired engineer

    We should study this subject more deeply. At least that's my opinion.
    Will Probiotics Replace the Increasingly Ineffective Antibiotics?
    On an almost daily basis both world and national news gives us an update on the increase in hospital infections that are not responding to even the best antibiotics available in our medical arsenal.

    1. Sue Ieraci

      Public hospital clinician

      In reply to Lucien Beauley

      Yes - older antibiotics are less useful as organisms are selected for resistance.

      No - they won't be replace by pro-biotics, which do not prevent or fight infection.

  4. Daan De Weerdt

    logged in via Twitter

    Why is this sentence in the article?
    "And the deep, aching muscle pain produced by viral infections may be more likely to lead to serious muscle damage when combined with binge drinking."
    Antibiotics for viral infections will do you more harm than good...

  5. Firozali A.Mulla


    I guess any pill has to be taken after food as the doctors recommend, all medication ought to be taken after meal when the plasma level works in normal way and the liver does not take the excess dose impromptu the intestines work first on the medication so it is safe on the stomach and bile may help while the track of fluids also are importane you ought to take more water say more then usual I thank you Firozali A.Mulla DBA

    1. Sue Ieraci

      Public hospital clinician

      In reply to Firozali A.Mulla

      Depends on the formulation of the medication, Forozali. Medicines vary widely in their chemistry and pharmacodynamics. Some are highly protein-bound. Some are mostly in the serum, others in the tissues. Some are slow-release formulations. Some undergo enterohepatic circulation via the bile, some are renally excreted...... there is no single rule.

      This is one of the things we hope pharmacists will tell us when they dispense medication.

    2. Steve Phillips

      Nurse Practitioner

      In reply to Sue Ieraci

      I am very encouraged by pharmacists increasing involvement in clinical matters. Too few Drs give proper advice and or instruction to their patients. Time and again I have patients who are on a medication but have no clue as to its effects or potencial adverse effects. Half the time they dont know what is wrong with them because the Dr dint bother or know how to explain it.

    3. Chris Sharp

      Pharmacy Student

      In reply to Firozali A.Mulla

      Oh, it isn't always the case. In fact, quite often it isn't the case, with some antibiotics recommended immediately before food, some with food, some after food, some at least half an hour before or two hours after food; and with some it simply doesn't matter.

      This is for a range of reasons: Maybe the drug acts as a local irritant, or the low pH of the stomach degrades the drug. Maybe the drug chelates to common minerals in food and being bound, can't be absorbed. Maybe taking it with food slows the rate of transit from the stomach for long enough that instead of getting a good peak concentration in the bloodstream, you get a lower and delayed peak which doesn't get high enough to reach the therapeutic concentration range or to stay there long enough between doses. I'm sure there's a couple of other reasons too but they're not coming to me right now or to the three other students I just checked with, sorry :(

  6. Rhonda Nay

    Emeritus Professor La Trobe University at La Trobe University

    Thank God I have not been destroying expensive drugs all this time!! Now I can do it without the guilt.