Does Alcohol Affect Antibiotics, What Are The Risks?

Everyone has heard that we should not consume alcohol if we are taking some kind of antibiotic. Among the reasons why this combination is avoided is the loss of antibiotic efficacy, increased alcohol toxicity, the occurrence of side effects, and even higher risk of liver damage.

A simple Google search for the terms “alcoholic beverages and antibiotics” allows us to find dozens of websites that advocate unrestricted alcohol abstinence for patients undergoing antibiotic treatment.¬†Many of these sites cite physicians and provide supposed scientific explanations for the risk of this association.

Unfortunately, the Internet is full of pseudo-scientific articles, which in the eyes of the lay population may appear to be very well grounded but lack minimal scientific evidence to support their views.

Does Alcohol Affect Antibiotics, What Are The Risks?

In the light of current scientific knowledge, there is no single answer to the question: ”¬†who is taking antibiotics can drink?¬†“.

For this answer to be given correctly, we need to know what antibiotic is being taken, what infection is being treated, what is the patient’s clinical condition, and how much alcohol the individual intends to take.

To summarize in just one sentence all that will be explained in this article, we can say that for most patients and for most classes of antibiotics, there is no problem in ingesting alcohol moderately during the course of antibiotics.

Our text will be divided into the following topics:

  • Why mixing alcohol and antibiotics may not be a good idea.
  • Antibiotics that¬†CONTRAINDICAM¬†¬†the consumption of alcoholic beverages.
  • What is the disulfiram effect.
  • Antibiotics that¬†¬†ALLOW¬†¬†moderate alcohol consumption.
  • Clinical situations should discourage the mixing of alcohol and antibiotics.

Read more: Does Amoxicillin Affect Birth Control

Why the Blend of Alcohol and Antibiotics May Not Be a Good Idea

Moderate and occasional amounts of alcohol, such as the social consumption of two wine glasses or two beer cans (or a dose of a distilled beverage), do not cause any interference with the effect of most antibiotics. In fact, even higher doses of alcohol do not usually cut off the effect of the antibiotic. The problem, as we will see next, is the side effects and the action of alcohol on the immune system.

In principle, the idea that total abstinence is required during antibiotic treatment is a myth. This is not a personal opinion, the British Medical Association (BMA) does not impose any restriction on the association of alcohol with most antibiotics (exceptions will be explained later).

The interesting thing is that this myth is quite common even among health professionals. A study in Britain showed that up to 76% of doctors surveyed feel that mixing alcohol with antibiotics should be banned in all cases, without exception.

It is important to note, however, that even though alcohol consumption is not banned during the use of most antibiotics, this mixing, especially at high doses, is not properly consequence-free.

Alcohol is a very irritating substance to the gastrointestinal mucosa, and as some common antibiotics, such as amoxicillin and azithromycin, frequently lead to nausea, vomiting, abdominal pain or diarrhea, the mixing of high doses of alcohol with antibiotics is discouraged to potentiate these adverse effects. If you are sick and taking antibiotics, alcohol is much more likely to cause adverse effects.

Another potential problem of this association is the fact that patients who need antibiotics are those who have some infection and therefore need a competent immune system to fight it. One or two beers eventually do not interfere with the body’s ability to fight infections, but high amounts of alcohol can actually impair the immune system’s action, making it difficult to cure the disease.

Another point that should be highlighted is the fact that alcohol is a substance that is metabolized in the liver by the same enzymatic pathways that metabolize some of the antibiotics.¬†Excessive and repeated alcohol consumption can leave the liver “busy” processing excess alcohol, causing the antibiotic to not be adequately metabolized.¬†This fact can cause not only a reduction in the action of antibiotics but also the accumulation of toxic metabolites, increasing the incidence of side effects.

In short, you can even have your beer or your usual glass of wine during a meal, even if you are under antibiotic treatment. However, if you are sick, it is wise to avoid alcohol, such as smoking, excessive physical exertion, poor eating, sleeping a few hours a night, and exaggerated sun exposure. There is, therefore, in most cases, no formal contraindication, it is just a matter of common sense.


Antibiotics that contraindicate alcohol consumption

Although the association of alcohol and antibiotics is safe in most cases, there are important exceptions. Some classes of antibiotics may undergo significant interaction, even with low doses of alcohol. Others, such as metronidazole and tinidazole, can cause serious side effects, known as the disulfiram effect (I explain later what this effect is).

So if you’re feeling well, have a party scheduled for the weekend, want to drink responsibly, but you’re on the final stretch of antibiotic treatment, the best option is to research if your antibiotic fits into the small group of drugs that contraindicate the consumption of alcoholic beverages.

Antibiotics that can NOT in any way be mixed with alcohol are those that can cause the disulfiram effect. Are they:

  • Metronidazole.
  • Tinidazole.
  • Cefotetan.

Even metronidazole or tinidazole in cream for vaginal application may cause a disulfiram effect. It is important to note that many gynecological creams may have 2 or 3 different substances in their composition, with metronidazole or tinidazole being one of them.

To avoid the occurrence of the disulfiram effect, the patient must be at least 72 hours without taking the antibiotics to be able to consume any alcoholic beverage.

Rarely, the antibiotic sulfamethoxazole-trimethoprim, known by the trade name  Bactrim, may also cause a disulfiram effect. In general, this only occurs if the patient consumes a large number of alcoholic beverages. But as some organisms may be more sensitive than others, for safety, if you are taking Bactrim, avoid alcoholic beverages.

In addition to antibiotics, other drugs used to treat infections such as antiviral, antiparasitic and antifungal drugs can also cause side effects if mixed with alcohol. The most important are:

  • Griseofulvin (antifungal): may cause a disulfiram effect.
  • Voriconazole (antifungal): interferes with the antifungal effect.
  • Ketoconazole (antifungal): increases the risk of liver damage.
  • Didanosine (antiretroviral): increases the risk of pancreatitis.


Other side effects of alcohol-antibiotic combination

The antibiotics mentioned above are those that can cause the most serious reactions if ingested along with alcohol. However, there are still some other antibiotics that can cause other types of reactions, and therefore, their association with alcoholic beverages should also be avoided. Are they:

  • Linezolid: may cause a hypertensive crisis if consumed along with alcoholic beverages rich in tyrosine, such as beer or red wine.
  • Isoniazid, rifampicin, or pyrazinamide:¬†these drugs have an increased risk of hepatic toxicity (liver damage), therefore, alcohol use, especially frequently, should be discouraged.
  • Erythromycin or doxycycline:¬†Alcohol may reduce the effectiveness of these antibiotics.¬†Erythromycin may also accelerate the emptying of the stomach, causing the ingested alcohol to be absorbed more quickly, which leads to higher blood levels of alcohol.


What is the disulfiram effect?

Disulfiram, sold commercially under the name Antabuse, is a substance used in the treatment of alcoholism. Disulfiram prevents the liver from eliminating the more toxic metabolites of alcohol, such as acetaldehyde, which is one of the substances responsible for hangover symptoms that occurs in individuals who drink too much.

Because disulfiram prevents the liver from metabolizing acetaldehyde produced by alcohol, its blood level is up to 1000% higher. When the patient on disulfiram drinks alcohol, even in small doses, he gets intoxicated quickly and feels the side effects of the treatment, which are similar to a colossal hangover, with vomiting, palpitations, heat, excessive sweating, respiratory distress, intense headache, and drop in blood pressure.

The individual feels very uncomfortable as if he is on the verge of collapse, so he can not continue drinking. If even feeling poorly the patient insists on drinking alcohol, the drug can lead to coma or death.

The antibiotics mentioned in the previous topic, especially metronidazole and tinidazole, may cause a similar effect as disulfiram. Therefore, alcohol consumption should be strongly discouraged from the 24 hours before the start of treatment until 72 hours after the end of antibiotic treatment.

Antibiotics that allow moderate alcohol consumption

So far, we have cited 10 antibiotics that should not be mixed with alcohol. If you are taking any antibiotics that have not been mentioned above, there is no scientific evidence to contraindicate moderate alcohol use during treatment.

To be more specific, there is no formal contraindication to alcohol consumption in small doses for those who are using amoxicillin, azithromycin, ciprofloxacin, levofloxacin, penicillin, cephalexin, ceftriaxone, or other common antibiotics.

Clinical situations that should discourage the mixing of alcohol and antibiotics

As we discussed at the beginning of the text, the fact that there are no formal contraindications to the use of alcohol with certain types of antibiotics does not mean that this association is completely safe. Remember, the patient under antibiotic treatment is ill, abusing alcohol will do you no good.

If the patient has a serious or potentially serious infection, it is obvious that alcohol consumption should be avoided, even if the drink has no direct interaction with the ongoing antibiotic. The issue is not the antibiotic itself, but the disease. The same reasoning applies to patients with some liver problems, even if temporary, because the alcohol-antibiotic combination may increase the hepatotoxicity of both.

Studies show that patients being treated for sexually transmitted diseases (STDs) are at greater risk of having unprotected sex before the end of the course of antibiotics (before they are cured, therefore) if they consume alcoholic beverages. This behavior puts other people at risk and promotes the spread of venereal diseases. Therefore, every STD patient being treated should avoid alcohol consumption.