Flagyl – Information, Uses, Side Effects and Dosage


Drug Trade Name: Flagyl

Category: Antibiotic and Antiprotozoal

Generic Name: metronidazole

Introduction and Quick Information:


Flagyl is an antibiotic and antiprotozoal medicine that is used for the treatment of infections caused by anaerobic bacteria and parasites in various body parts. Sexually transmitted infections like trichomoniasis and bacterial vaginosis can also be treated by using Flagyl. It works by inhibiting the synthesis of nucleic acid by disrupting the microbial DNA. This results in breakage of DNA strand and the microbe gets killed.    

Is It Approved by U.S. FDA?     

Flagyl was approved by the U.S. Food and Drug Administration (FDA) on 18th July 1963.

Usage and Benefits of Flagyl:

Being an antibiotic, Flagyl can be used for treating a number of diseases, like:

  • Bacterial vaginosis
  • Trichomoniasis
  • Amoebic infections in children
  • Crohn’s disease (off-label use)
  • Pelvic inflammatory disease.

Flagyl Side Effects:

Some of the commonly observed side-effects related to Flagyl use are discussed below:

  • Abdominal cramps
  • Weight loss
  • Heartburn
  • Metallic taste in mouth
  • Trouble sleeping
  • Trouble with swallowing
  • Dry mouth

If you experience any side-effect other than those listed above, please consult your healthcare provider.

People suffering from a nervous disorder, liver disease, anemia or epilepsy are required to take special precautions before taking Flagyl medication. Doctor’s advice will be highly beneficial for them.

General Recommended Dosage of Flagyl:

Follow the instructions given by your doctor while taking the medicine as the dose is recommended according to your current medical condition. Flagyl tablets should be swallowed as a whole. It should not be crushed or broken. 

In Case I Miss the Dose?


If you miss your dose and it is almost time for your next scheduled dose, we recommend you to skip the missed dose and continue with your next scheduled dose.You should not take extra medicine to make up for the missed dose as that can result in overdose.

In Case I Take Overdose?

Overdose should be avoided at all costs. Sometimes people take extra dose intentionally, to make up for the missed dose missed or, unintentionally. Whatsoever is the case, the result is harmful and therefore, medical attention should be sought immediately. Vomiting, loss of balance or coordination, dizziness, numbness and tingling, and seizures are some of the symptoms of overdose.

Drug Interactions of Flagyl:

Some of the drugs that interact with Flagyl are:

  • albuterol sulfate (Accuneb)
  • ondansetron hydrochloride (Zofran)
  • amoxicillin (Amoxil)
  • alprazolam (Xanax)
  • aspirin (Aspirin)
  • acetaminophen (Tylenol)
  • atenolol(Tenormin)
  • levothyroxine sodium (Synthroid)
  • lisinopril (Lisinopril)
  • levofloxacin (Levaquin)

Lifestyle and Food Habits You Must Follow When on Flagyl:

Visit your doctor for regular check up, so that he can assess your medical condition and the efficacy of treatment. Consume a balanced diet that will help your body in strengthening your immune system.  

Consumption of alcohol and products containing propylene glycol should be avoided while on Flagyl and up to 3 days after stopping the treatment.

There is a possibility that the drug might cause dizziness. Therefore, driving, using heavy machinery and other such works that require alertness should be avoided. 

This drug might interfere with the working of live bacterial vaccines like typhoid vaccine. therefore, it is advised not to go for any vaccination while on the drug, unless recommended by a doctor.

How safe is Flagyl for pregnant women or Nursing mothers?

Flagyl comes in the U.S. FDA category B, which means that it might be given during pregnancy. If the mother has bacterial vaginosis or trichomoniasis, then the use of Flagyl is contraindicated during the first trimester of pregnancy. During second and third trimesters of pregnancy, use is not recommended, unless it is absolutely necessary. 

Since the drug gets secreted in breast milk, the drug should not be taken by nursing mothers. If the mother undergoes a single dose treatment, then she should avoid breastfeeding for 12 to 24 hours.   

Complications and Conditions Possible Due to Prolonged Use of Flagyl:

Flagyl should not be taken for a longer duration than recommended by your doctor. Prolonged use of Flagyl can result in seizures, aseptic meningitis, encephalopathy, superinfection, and neuropathies. 

Availability of Flagyl:

In the U.S., Pfizer markets Flagyl as a prescription drug in the form of tablets, capsules, and extended-release tablets at various government controlled health centers and medical stores across the country.  Flagyl is also available as an injectable form.