From the Guidelines
It is recommended to wait at least 24 hours after completing metronidazole treatment before consuming alcohol. Metronidazole, an antibiotic commonly used to treat various bacterial and parasitic infections, can interact with alcohol to cause a disulfiram-like reaction [ 1 ]. This reaction occurs because metronidazole inhibits the enzyme aldehyde dehydrogenase, which is responsible for breaking down acetaldehyde, a toxic byproduct of alcohol metabolism. When alcohol is consumed while this enzyme is inhibited, acetaldehyde accumulates in the body, leading to unpleasant and potentially dangerous symptoms including severe nausea, vomiting, flushing, headache, rapid heart rate, chest pain, and low blood pressure.
Key Considerations
- The risk of a disulfiram-like reaction is highest with oral forms of metronidazole [ 1 ].
- Patients should be advised to avoid using alcohol during treatment with metronidazole and for 24 hours thereafter [ 1 ].
- If you experience any concerning symptoms after consuming alcohol following metronidazole treatment, seek medical attention immediately.
Additional Information
The provided evidence from [ 1 ] discusses the diagnosis and treatment of Clostridium difficile in adults, which is not directly relevant to the question of how long after metronidazole treatment alcohol can be consumed. Therefore, this information is not considered in the recommendation. The most relevant and recent guideline evidence [ 1 ] suggests a 24-hour waiting period after metronidazole treatment before consuming alcohol.
From the FDA Drug Label
Alcoholic beverages should be avoided while taking metronidazole tablets and for at least one day afterward. Alcoholic beverages should not be consumed during metronidazole therapy and for at least one day afterward because abdominal cramps, nausea, vomiting, headaches, and flushing may occur
Alcohol Consumption After Metronidazole Treatment:
- Alcohol can be consumed at least one day after completing metronidazole treatment.
- It is recommended to avoid alcohol during metronidazole therapy and for at least one day afterward to prevent adverse reactions such as abdominal cramps, nausea, vomiting, headaches, and flushing 2.
From the Research
Metronidazole and Alcohol Consumption
- There is no specific time frame provided in the studies for when alcohol can be consumed after completing metronidazole treatment 3.
- A study from 2014 found that the warning against simultaneous use of alcohol and metronidazole appears to be based on laboratory experiments and individual case histories, and recent research does not confirm a clinically relevant interaction between ethanol and metronidazole 3.
- Another study from 2024 reported a case of a patient who experienced disorientation and confusion after taking metronidazole and ciprofloxacin for acute diverticulitis, but this was not directly related to alcohol consumption 4.
- A 2009 study reported a case of a patient who developed a disulfiram-like reaction after taking ornidazole and alcohol, highlighting the need for clinicians to advise patients to restrict intake of alcohol if they are being prescribed imidazole derivatives 5.
- A 1998 study discussed the disulfiram-ethanol reaction and a similar reaction that can occur with trimethoprim-sulfamethoxazole (cotrimoxazole) and ethanol, but did not provide information on metronidazole and alcohol consumption 6.
- A 2000 study found that metronidazole increases intracolonic but not peripheral blood acetaldehyde in chronic ethanol-treated rats, suggesting that the mechanism behind metronidazole-related disulfiram-like reaction might be located in the gut flora instead of the liver 7.