What Happens When Metronidazole (Flagyl) And Alcohol Are Mixed?

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The Impact Of Mixing Metronidazole And Alcohol

Although it is one of the lesser known drugs, Metronidazole (aka Flagyl) is a strong antibiotic prescribed to treat a variety of bacterial and parasitical infections.

Since the liver and intestines process and break down Flagyl in the body, side effects primarily impact the gastrointestinal system and can include nausea, vomiting, diarrhea, stomach cramps and constipation.

Alcohol is also processed (metabolized) by the liver. Between two and eight percent of one alcoholic beverage is excreted through sweat and urine. The liver metabolizes the remaining percentage.

Initially, alcohol is converted to a toxic chemical called acetaldehyde (a form of formaldehyde), which is then converted to acetyl radicals. When someone drinks too much alcohol, the liver cannot keep up with converting acetaldehyde into acetyl radicals.

  • Accumulating acetaldehyde in the bloodstream can lead to vomiting, hangovers or worst of all, alcohol poisoning.

Consequences of Combining Metronidazole And Alcohol

Although it is not recommended, drinking a beer or small glass of wine while taking Flagyl typically causes minor side effects, like nausea, vomiting and diarrhea, in most people.

Depending how much alcohol is consumed, a disulfiram reaction resulting from mixing alcohol and Flagyl could last up to two hours. If symptoms are severe, emergency medical treatment may be necessary to prevent dehydration and/or fainting due to hyperventilation. Alcoholics taking disulfiram to suppress cravings should not take Flagyl.

Occasionally, mixing metronidazole with alcohol may trigger reactions resembling signs of disulfiram reaction because alcohol interferes with the ability of the liver to metabolize metronidazole.

Side effects of a disulfiram reaction can include:

  • Throbbing headache
  • Flushing/sweating
  • Nausea/vomiting
  • Rapid heartbeat
  • Heart palpitations
  • Dizziness
  • Blurry vision

Psychotic reactions such as hallucinations, paranoid delusions and extreme agitation could even occur in alcohol abusers who have small amounts of disulfiram in their bloodstream.

In rare cases, some people are susceptible to metronidazole blocking the metabolization of propylene glycol by the liver. Propylene glycol is a commonly used ingredient found in injectable, oral and topical medications to facilitate dispersion of the medication.

Excess amounts of propylene glycol in the body could cause

  • tachycardia
  • seizures
  • acute kidney failure

According to drugs.com; “Patients treated with metronidazole should continue to avoid using any products containing alcohol or propylene glycol for at least 3 days until after completion of therapy.”

What Other Substances Should Not Be Combined with Metronidazole?

If you are prescribed Flagyl, always tell your physician if you are currently taking or plan on taking any one of the following:

  • Ibuprofen
  • Aspirin
  • Benedryl
  • Antidepressants
  • Mucinex
  • Lyrica
  • Hydrocodone/acetaminophen
  • Acetaminophen
  • Probiotics
  • Prednisone
  • Vitamins B12, C or D3
  • Warfarin
  • Xanax

Mixing Alcohol and Antibiotics Overview

Most antibiotics will remain effective if alcohol is consumed with them. However, the ability for some antibiotics to eliminate infectious bacteria or parasites may be significantly reduced by alcohol. For example, an antibiotic called doxycycline loses its effectiveness when mixed with alcohol. Heavy alcohol drinkers who must take doxycycline for an infection may need their doctor to increase the dose of doxycycline just to get rid of the infection.

(image courtesy of https://dailymed.nlm.nih.gov/)