The Ultimate Guide to Metronidazole Tablet Uses: What You Need to Know

Metronidazole is an antibiotic and antiprotozoal drug belonging to the nitroimidazole group.

Used to eliminate bacterial and protozoal infections. It is also available in tablet, syrup and IV form. It is often used for stomach and skin ailments. 


Metronidazole Tablet Uses

Metronidazole is given to eliminate infections caused by bacteria and protozoa.

Anaerobic infection  – There are some bacteria that do not require oxygen to survive. These are what we call anaerobic bacteria.


metronidazole tablet uses


Metronidazole works very effectively against such bacterial infections as –


Pelvic Inflammatory Disease (PID)

Indra-abdominal Infections

Liver infection (liver abscess)

Deep Skin and Soft Tissue Infections


Brain infection

Periodontal disease

Infection inside the vagina (Bacterial Vaginosis) etc.
Protozoal Infections  –
 Metronidazole works very well against protozoal infections.
Like amebiasis, giardiasis, trichomoniasis, etc.
H.Pylori Infection  –
 H. pylori bacteria causes peptic ulcer in the stomach.
Metronidazole works very well for ulcers caused by H. pylori.
Along with this, other antibiotics and proton pump inhibitors (PPIs) are also given.
Antibiotic-Associated Colitis  –
Metronidazole works best in Antibiotic Associated Colitis. In this disease, the patient gets severe diarrhea and swelling in the large intestine.

Mode of Action of Metronidazole

Metronidazole is a pro-drug i.e. when we take metronidazole in the form of medicine, it does not go into our body in active form and remains inactive.
When it goes inside the microorganism (bacteria, protozoa), it becomes active by reacting with a special type of protein (Ferredoxin) present inside the microorganism which is found only in the microorganism.
This special type of protein (Ferredoxin) is not found in human cells.
Now active metronidazole produces a toxic chemical called ROS (Reactive Oxygen Species) in the body of bacteria or protozoa.
This ROS damages the bacterial DNA and breaks the DNA strand, killing the bacteria’s ability to grow and repair itself.
In this way, the bacteria gets killed. It is very effective against anaerobic bacteria.
Anaerobic bacteria are those that live without oxygen.

Metronidazole works in another way also, metronidazole blocks electron transport inside bacterial cells.
Due to a lack of electron transport, ATP cannot be produced inside the cell and ATP is the main source of energy of a cell.
Due to the non-availability of energy, no action takes place inside the cells and the cell dies.
With the death of cells, bacteria, and protozoa also die.
Metronidazole has properties to kill bacteria or protozoa. They are also known as Bactericidal and Parasiticidal.
It is worth noting that metronidazole kills bacteria and protozoa, it does not work on viruses and fungi.

Metronidazole Side Effects

The most common side effects of metronidazole are

1) Abdominal pain

2) Vomiting or Nausea

3) Diarrhea

4) Metallic Taste in the mouth

These side effects go away in most cases by drinking milk or eating food. There are some other side effects which can be serious like

1) Allergic reaction

2) Tremors

3) Headache

4) Dizziness

5) Confusion

6) Decreased white blood cells and platelets

7) Numbness of body or hands and feet


Metronidazole Drug Interactions

Metronidazole can increase or decrease their effects when combined with certain medicines or chemicals. 

So do not take any medicine without a doctor’s advice like

1) Blood thinners or antiplatelet medicines can cause internal bleeding when taken with Metronidazole.

2) Lithium is a drug given to Psychotic patients. Its use with metronidazole can increase the toxicity of lithium in the body.

3) Metronidazole should not be taken with medicines that act on liver enzymes, otherwise its side effects may appear.

4) Metronidazole should not be taken with alcohol. This can have serious consequences. Alcohol should be consumed only 48 hours after metronidazole.


Who Should not Take Metronidazole

1) Pregnant women especially in the first trimester

2) Lactating women

3) Patients with liver disease

4) Patients with a blood disorder

5) Patients with neurological disorders

6) It is safe for kidney patients as it is metabolized in the liver.

But patients who are on dialysis should not take metronidazole without a doctor’s advice.

Metronidazole Tablet Dosage

Metronidazole 400 mg three times a day (TID) is taken according to the severity of the disease. 

It can be given continuously for 10 days according to the infection.

10 mg/kg/day is given to children. The dosage in children also depends on the severity of the disease.




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