Furazolidone: Uses, Mechanism of Action, Side Effects, Precautions, Interactions and Administration

It is an antibacterial agent of nitrofuran and a monoaminooxidase inhibitor.


Furazolidone has been used in human and veterinary medicine. It has a broad spectrum of active activity against bacteria:

  • Gram positive.
  • Clostridium perfringens.
  • Corynebacterium pyogenes.
  • Streptococci.
  • Staphylococcus
  • Gram negative.
  • Escherichia coli.
  • Salmonella dublin.
  • Salmonella typhimurium.
  • Shigella.
  • Protozoa.
  • Giardia lamblia.
  • Especie eimeria.
  • Histomonas meleagridis.

Use in humans:

In humans, it has been used to treat diarrhea and enteritis caused by bacteria or infections by protozoa. It has been used to treat traveler’s diarrhea, cholera and bacteremic salmonellosis. The use in the treatment of Helicobacter pylori infections has also been proposed.

Furazolidone is also used for giardiasis (due to Giardia lamblia), although it is not a first-line treatment.

Use in animals:

As a veterinary drug, furazolidone has been used with some success to treat salmonids in Myxobolus cerebralis infections.

It has also been used in aquaculture.

The use of furazolidone in animals intended for food is currently prohibited by the FDA under the Law on the Clarification of the Use of Animal Medicines, since it is a nitrofuran antibiotic.

Use in the laboratory:

It is used to differentiate micrococci and staphylococci.

Mechanism of action

It is believed to work by cross-linking DNA.

Side effects

Although it is an effective antibiotic when all others fail against infections that are extremely resistant to medications, it has many side effects. Including the inhibition of monoamine oxidase and as with other nitrofurans in general, the minimum inhibitory concentrations also produce systemic toxicity:

  • Tremors
  • Convulsions
  • Peripheral Neuritis.
  • Depression of spermatogenesis.
  • Headache.
  • Stomach ache.
  • Sickness.
  • Vomiting, dizziness or weakness.

This medicine can make the urine brown. Do not be alarmed, it’s normal. If you notice other effects not mentioned above, contact your doctor or pharmacist.

When to call the doctor?

Some side effects can occur especially during the first few days as your body adjusts to the medication. If any of these effects become bothersome or severe, inform your doctor.

Notify your doctor if you have:

  • Fever.
  • Acne.
  • Itch.
  • Muscle pains.
  • Redness
  • Trouble breathing.


Before using this medicine, inform your doctor about your medical history, especially: blood disorders (G6PD deficiency), allergies (especially drug allergies).

Avoid alcohol consumption during therapy and for 4 days after taking this medication. It can cause a reaction that causes redness, fever, tightness in the chest and shortness of breath.

Be careful when performing tasks that require you to be alert if this medication makes you feel dizzy. Babies under one month old should not receive this medication. During pregnancy, this medication should only be used if it is strictly necessary. 

It is not known if this medicine passes into breast milk . Consult your doctor before breast-feeding .

Consult your doctor about the need to monitor the intake of foods containing tyramine. It is possible that consuming foods containing tyramine while using this medication may cause headache and / or increased blood pressure and could lead to a medical emergency.

Interactions with other medications

This medication should not be used with the following medications because very serious interactions may occur:

Before using this medication, tell your doctor about all the medications you use (prescription and non-prescription).


Take this medication orally, as directed, usually four times a day . It can be taken with food if stomach upset occurs.

For best results, take each dose at evenly spaced intervals throughout the day. This will ensure a constant level of medication in your blood. Take this medicine for the full prescribed time .

Stopping treatment too soon may lead to reinfection.