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Resisting alcohol intake might be very difficult for some people even in the course of antibiotic treatment. Some people say that it’s potentially dangerous to drink alcohol while taking antibiotics as it may weaken the effect of antibiotics. Not only that, some drugs when mixed with alcohol may cause serious side effects too. An example of this is the complication brought by Flagyl-alcohol interaction in the body.

What is Flagyl?

Flagyl, brand name of the drug metronidazole made by Pfizer, is a drug famous for treatment of bacterial and protozoan infections. It is also used to treat infections such as vaginosis, pneumonia, brain abscess, dental infections and fungi infected wounds. 

Drug Interaction Side Effects

Drinking alcohol on the duration of Flagyl treatment may result to similar effects of the drug disulfiram or antabuse, which can produce severe sensitivity to alcohol for treatment of chronic alcoholism. The effect of alcohol and Flagyl combined together may cause headache, nausea, vomiting, flushing of the skin, tachycardia (fast heart rate) and shortness of breath. However, there is no study yet to prove that these reactions are due to Flagyl and alcohol mixture, but physicians often inform their patients to abstain from alcohol during the Flagyl intake up to 3 days after undergoing antibiotic treatment. It is known to many people that alcohol is also present in small amounts on some beverages, this should be avoided too as it may produce similar reactions even consumed in minimal quantities.

Being similar to disulfiram or antabuse, most researchers believed that the Flagyl-alcohol mixture has the same reaction to the body. According to them, flagyl interferes with the break down of alcohol into acetaldehyde and then to acetic acid. In normal conditions, acetaldehyde is broken down into acetic acid by the liver. If this does not happen, there would be an increased amount of acetaldehyde levels in the bloodstream, causing nausea and vomiting to the drinker. There are also other side effects of Flagyl-alcohol interaction that can lead to more serious diseases such as seizures, food allergy, liver cirrhosis and hepatitis infections.

For pregnant women and for those who breastfeed, Flagyl is not recommended to take without prescription from the doctor. Alcohol is prohibited too, since it may cause several problems to the baby’s health. Though there are no reported defects on the babies with mothers who took Flagyl, there are reported miscarriages on the other hand. So it is advisable for mothers to avoid and even better not to take both drugs if possible.

What Studies Show?

Some researches show that it is not the Flagyl-alcohol mixture which causes the side effects. In a study using rats, Flagyl is proven to increase the amount of serotonin in the brain, which leads to the same side effects. The researchers also found out that acetaldehyde is further broken down into acetic acid and the level of acetaldehyde in the blood does not rise at its peak. Other researchers also said that there is a small percent of reported cases with these side effects, and most individuals are involved in other dietary factors. It still couldn’t be said that the side effects originated primarily from Flagyl and alcohol interaction. However, the researchers did not deny the fact that these effects may still occur in small subgroups.


Despite the fact that the adverse effects of Flagyl and alcohol in the body are not yet scientifically proven, it is still wise to avoid these two mixed up in your system.