METROGYL 400 Tablet 20's

Introduction About METROGYL 400 TABLET

Metrogyl 400 Tablet is commonly used for managing certain bacterial and protozoal infections. This medicine contains metronidazole, a trusted ingredient recognized for its effectiveness against infections of the stomach, intestines, gums, skin, joints, and other body parts. It is also commonly prescribed in scenarios such as dental infections, post-surgical care, or when specific parasitic infections like amoebiasis and giardiasis are identified by a healthcare provider. The use of this tablet is guided by a medical professional after a thorough assessment of your symptoms and laboratory results.

This medicine is typically suited for adults and adolescents who have been diagnosed with infections sensitive to metronidazole. Patients who may benefit from Metrogyl 400 include those dealing with stomach or intestinal infections, certain dental or gum issues, or infections after surgery. The dose and length of therapy depend on your age, the type of infection, and your doctor’s advice. In general, Metrogyl 400 is taken orally, preferably after meals to reduce stomach discomfort. It should be swallowed whole with water as per the schedule and dosage prescribed by your healthcare provider. It is important not to skip doses or stop the course early, even if symptoms improve, to avoid incomplete clearing of the infection.

Some important precautions need to be followed while using Metrogyl 400. Avoid alcohol during therapy and for at least 48 hours after the last dose, as combining with alcohol can cause unpleasant reactions (such as flushing, nausea, or rapid heartbeat). Let your doctor know about any existing medical conditions, especially if you have liver problems, a history of blood disorders, or nervous system issues. Regular monitoring may be recommended if you require prolonged treatment. Follow the directions for use and do not share your medicine with anyone else.

For pregnancy and breastfeeding, Metrogyl 400 should only be used on doctor’s advice. While some research suggests it can be used when clearly needed, inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding, so they can weigh the benefits and possible risks. Common side effects reported with Metrogyl 400 include nausea, vomiting, abdominal pain, metallic taste in the mouth, headache, and, sometimes, dizziness. Most side effects are mild and temporary, but any severe or persistent symptoms should be brought to your doctor’s attention promptly. Always keep your doctor informed about all your medicines and supplements before starting Metrogyl 400.

Uses Of METROGYL 400 TABLET

• Bacterial infections of the stomach, intestines, liver, gums, teeth, skin, joints, blood, lungs, bones, heart and brain.
• Parasitic infections such as amoebiasis, giardiasis and trichomoniasis.
• Stomach ulcers associated with Helicobacter pylori (as part of combination therapy)

Benefits of METROGYL 400 TABLET

Bacterial infection management

Bacterial infections occur when harmful bacteria enter the body and disrupt normal health, commonly affecting areas like the gastrointestinal system, skin, gums, and soft tissues. Metrogyl 400 Tablet (metronidazole) is used in the management of these infections, especially when bacteria sensitive to its action are involved. Accurate identification of the infection source by a healthcare provider is essential for safe and effective management. Patients should closely follow the prescribed dosage and schedule, as missing doses may reduce the effectiveness of infection control. To support successful management, pay attention to hygiene, handle medicines as directed, and carefully read all labels for usage instructions. Individuals with specific medical backgrounds, such as liver disease or past antibiotic allergies, should inform their healthcare provider before starting this medicine. Ensuring responsible use and adhering to the full course of therapy, as advised, supports optimal results and helps prevent resistance.

Protozoal infection management

Protozoal infections arise from single-celled parasites—such as amoebae or giardia—most often entering the body through contaminated food or water. Metrogyl 400 Tablet is commonly chosen for conditions like amoebiasis, giardiasis, and trichomoniasis due to its proven activity against these protozoa. Management of protozoal infections involves using the medication exactly as recommended after confirmation by medical assessment and laboratory tests. Along with proper medication use, patients should maintain strict hygiene—frequent handwashing, using safe drinking water, and consuming properly prepared foods—to limit both spread and recurrence. Do not share this medication with others, even if they have similar symptoms, and report any side effects such as nausea, metallic taste, or headache to your healthcare provider. Special care is advised for vulnerable groups—including pregnant or breastfeeding individuals—who should use the medicine only under professional supervision to ensure safety.

How METROGYL 400 TABLET Works

Metrogyl 400 mechanism of action

Metrogyl 400 Tablet contains metronidazole, a nitroimidazole compound that acts as a prodrug requiring biochemical reduction to become active. Once inside susceptible bacteria and protozoa—especially those thriving in low-oxygen (anaerobic) environments—the drug is converted into reactive metabolites by microbial enzymes. These metabolites interact with microbial DNA, causing DNA strand breaks and inhibiting nucleic acid synthesis. This action disrupts essential DNA functions, preventing bacteria and parasites from multiplying and ultimately resulting in their elimination. Human cells and aerobic bacteria are largely unaffected because the activation process requires a low-oxygen environment unique to anaerobic pathogens.

How Metrogyl 400 Targets Bacteria and Parasites

Metrogyl 400 is specifically effective against a wide range of anaerobic bacteria and protozoal pathogens. The unique property of these microbes to activate metronidazole ensures targeted action: the drug is taken up by the pathogen, where it undergoes reduction to generate powerful intermediates that bind to and damage its DNA. This targeted mechanism means that the medicine disrupts only the DNA of specific bacteria and protozoa, sparing most healthy cells and beneficial microbial flora. As a result, Metrogyl 400 is a preferred choice for conditions like gastrointestinal, dental, skin, and reproductive tract infections caused by anaerobic bacteria and certain protozoa (including amoebiasis, giardiasis, and trichomoniasis). The drug’s selectivity and ability to reach effective concentrations in tissues make it a reliable agent for broad-spectrum infection control while minimizing the impact on the body’s natural systems.

How to use METROGYL 400 TABLET

Metrogyl 400 dosage instructions

• Follow your healthcare provider’s prescription: Dosage and duration depend on age, specific infection, and medical condition.
• Typical adult dose: Often 400 mg two or three times daily, adjusted based on infection type.
• Pediatric use: Dose is weight-based and set by the doctor—do not estimate or alter.
• Timing: Take at evenly spaced intervals (e.g., every 8 or 12 hours) for consistent levels in the body.
• Full course: Complete the entire prescribed duration, even if symptoms improve earlier.

Metronidazole tablet administration

• Swallow whole: Do not chew, break, or crush the tablet.
• Take with or after food: This helps reduce the chance of stomach upset.
• Use water: Drink a full glass of water with each dose.
• Do not skip doses: Maintain regular dosing to ensure consistent effectiveness.
• Missed dose instructions: If forgotten, take as soon as remembered. If close to the next dose, skip and continue regular schedule—do not double.

Administration Tips for Best Results

• Set reminders: Use a medication reminder or alarm to avoid missing doses.
• Consistent timing: Take at the same time(s) daily to build a routine.
• Avoid alcohol: Do not consume alcohol during the course and for at least 48 hours after the last dose.
• Inform your provider: Disclose any other medications, allergies, or health issues before starting.

What if I forgot to take METROGYL 400 TABLET

If you forget to take your scheduled dose of Metrogyl 400 mg Tablet, take it as soon as you remember. However, if it is nearly time for your next dose, skip the missed dose and continue with your usual dosing schedule. Do not take two doses together to make up for the missed one, as this can increase the risk of side effects without improving effectiveness. Setting daily medication reminders or using a pill organizer can help you stay on track. Consistently taking your medicine at the same time each day supports the best possible outcomes. If you repeatedly miss doses or are unsure of what to do, contact your healthcare provider or pharmacist for guidance.

Overdose

Taking more than the prescribed amount of Metrogyl 400 mg Tablet can increase the risk of harmful effects such as nausea, vomiting, unsteadiness, numbness, or, in rare cases, seizures and confusion. If you or someone else may have taken too many tablets, seek medical help or contact the nearest healthcare facility immediately, even if there are no immediate symptoms. Quick professional advice is important to minimize any potential risks, as supportive care or monitoring may be needed based on the amount consumed and the individual’s health status. Always keep Metrogyl 400 mg Tablet out of reach of children and store it safely to prevent accidental ingestion. If you are concerned or have questions about the dose taken, reach out to your healthcare provider or pharmacist as soon as possible.

Side Effects Of METROGYL 400 TABLET

Most Common Side Effects of METROGYL 400MG TABLET are:

• headache
• lack of appetite
• nausea
• dryness in mouth
• metallic taste in mouth
• stomach cramps
• dizziness

When to Seek Medical Attention?

Stop taking METROGYL 400MG TABLET and consult your doctor immediately if you experience any of the following side effects:

• stomach pain, lack of appetite, nausea, vomiting, fever, tiredness, weakness, jaundice (yellowing of skin and whites of the eye), dark urine, putty or mastic-coloured stools, skin itchiness
• signs of severe allergic reactions (such as skin rash, itching, swelling of the face, lips, throat or tongue causing difficulty in breathing or swallowing)
• severe skin reactions (such as widespread skin rash, blistering, peeling or bleeding on any part of the skin with fever, chills, enlarged lymph nodes and malaise or pink or reddish skin lesions on palms or soles)
• signs of brain disease called encephalopathy (such as fever, stiff neck, headache, seeing things which aren’t there, confusion, difficulties in using your arms and legs, problems with speaking)
• signs of blood disease (such as unexpected infections, mouth ulcers, bruising, gum bleeding, or severe tiredness)
• signs of a liver problem (such as yellowing of skin and eyes)
• severe stomach pain which may reach through to your back (signs of inflammation in the pancreas)

Warning & Precautions

Pregnancy

Consult your doctor

METROGYL 400MG TABLET is generally considered safe to use during pregnancy. While there are limited human studies, animal research has shown low or no adverse effects to the developing baby. Please consult with your doctor for further guidance.

Breastfeeding

Contraindicated

METROGYL 400MG TABLET may pass through breast milk. Therefore, it is not suitable for use in breast-feeding women. Consult your doctor for advice.

Driving and Using Machines

Use with Caution

Do not drive or handle any machines if you experience dizziness, sleepiness, hallucination, or confusion while taking this medicine.

Alcohol

Consult your doctor

Avoid consumption of alcohol during management with METROGYL 400MG TABLET as it may cause unpleasant side effects such as nausea and vomiting, stomach pain, hot flashes, irregular heartbeat, thirst, and headache.

Kidney

Use with Caution

METROGYL 400MG TABLET should be used with caution in patients with kidney problems (including dialysis). Therefore, consult your doctor before taking it.

Liver

Use with Caution

METROGYL 400MG TABLET should be used with caution in patients with liver disease. Dose adjustment of METROGYL 400MG TABLET may be needed. Therefore, consult your doctor before taking it.

Allergy

Contraindicated

Do not take METROGYL 400MG TABLET if you are allergic (hypersensitive) to Metronidazole or any other ingredients of this medicine.

Use In Pediatrics

Use with Caution

METROGYL 400MG TABLET should be used with caution in children and adolescents (aged below 18 years). Therefore, consult your doctor before taking it.

Use In Geriatrics

Use with Caution

METROGYL 400MG TABLET should be used with caution in elderly patients. Therefore, consult your doctor before taking it.

Other Warnings for METROGYL 400 TABLET

Before taking METROGYL 400MG TABLET, inform your doctor if you:

• have any diseases affecting your nervous system
• have Cockayne syndrome (a rare genetic disorder characterized by short stature, low intellectual ability and neurological problems)
• have blood dyscrasias (a blood condition affecting blood components, bone marrow, lymph and blood vessels)
• Have a history of seizures

Safety Advice

• Be Alert for Rare Neurological Symptoms: Long-term or high-dose use can sometimes cause serious nerve problems, such as unusual numbness, tingling, burning sensations in hands or feet, unsteadiness, seizures, or changes in speech or coordination. Immediately discontinue the medicine and consult your doctor if you notice these symptoms, especially during prolonged therapy.
• Monitor for Serious Mental Health Effects: Some individuals may experience confusion, mood changes, hallucinations, or even thoughts of self-harm. If you or those around you notice changes in behavior, confusion, or seeing/hearing things that are not present, stop the medicine and seek urgent medical help.
• Recognize Early Signs of Serious Allergic Reactions: Watch for swelling of the face, lips, tongue, throat, or difficulty breathing and swallowing, along with skin rashes or hives. These can indicate a severe allergic reaction and require immediate medical attention.
• Sensitivity in Individuals With Liver Problems: Patients with underlying liver disease need closer monitoring, as metronidazole can rarely cause or worsen liver problems (signs include yellowing of eyes/skin, dark urine, severe fatigue); dose adjustments may be necessary in such cases.
• Early Detection of Blood or Immune Issues: Rarely, Metrogyl 400 mg Tablet can affect blood cell counts, leading to frequent infections, unexplained bruising, bleeding gums, or extreme tiredness. Report these symptoms promptly as they may signal blood-related complications.
• Watch for Unusual Visual or Brain Symptoms: Blurred or double vision, eye pain, persistent headache with a stiff neck, or sensitivity to light may be signs of central nervous system effects such as meningitis or encephalopathy. Immediate medical review is necessary if these symptoms appear, especially if accompanied by fever or inability to tolerate light.
• Potential for Heart Rhythm Disturbance: Though rare, this medicine may affect the heart’s electrical system, potentially causing a type of irregular heartbeat called QT prolongation. If you feel sudden fainting, chest pain, or palpitations, consult a doctor promptly.
• Drug Interactions Worsening Side Effects: Some medicines (like warfarin, lithium, antiepileptics, or ciclosporin) can interact and increase the risk of toxicity or reduce the safety of Metrogyl 400 mg Tablet. Inform your doctor about all other drugs or supplements you use to minimize the risk of interactions.
• Prompt Action in Overdose or Accidental Ingestion: Signs of overdose include unsteadiness, vomiting, confusion, or seizures. Keep the medicine out of children’s reach and seek immediate medical help if accidental overdose is suspected.

Diet and Lifestyle Advice

• Avoid Alcohol: Strictly avoid all alcoholic drinks and products (including certain cough syrups, tonics, and mouthwashes) during Metrogyl 400 mg Tablet therapy and for at least 48 hours after finishing the course. Combining this medicine with alcohol may cause flushing, nausea, vomiting, rapid heartbeat, and headache.
• Take with Food: To minimize the chance of stomach upset or nausea, take Metrogyl 400 mg Tablet with or just after a meal and a full glass of water. Eating a light, non-spicy meal can further support digestive comfort.
• Normal Diet: No specific food restrictions apply (such as dairy or calcium), so you can generally continue your usual balanced diet. Maintain regular meals to help your body recover and support healing.
• Limit Caffeine: If you notice feeling unusually jittery, anxious, or have difficulty sleeping, consider moderating caffeine intake (from coffee, energy drinks, or tea), as metronidazole can slightly slow the breakdown of caffeine in some individuals.
• Adequate Hydration: Drink enough water throughout the day, especially if you experience loose motions or fever along with your infection. Proper hydration supports recovery and reduces side effect risk.
• Practice Good Hygiene: Maintain strong hand hygiene, especially before eating and after using the restroom, to prevent the spread or recurrence of infection. For those taking Metrogyl for gastrointestinal or protozoal conditions, use safe drinking water and avoid food from unhygienic sources.
• Healthy Lifestyle: Ensure good rest, follow prescribed medicine dosage timings, avoid unnecessary stress, and do not share your medicine with others. Adhering to the prescribed medicine schedule and rest will support your recovery.
• Monitor for Side Effects: Stay aware of symptoms like metallic taste, nausea, headache, or dizziness. Keep a simple diary of any new or unusual symptoms and notify your healthcare provider if you become concerned.
• Before New Medications: Always inform your doctor or pharmacist about Metrogyl 400 mg Tablet if you’re starting any new medicine, vitamin, or herbal supplement during your course.

Metrogyl 400 mg Tablet vs. Tinidazole: Which is more effective for treating protozoal infections?

Is Metrogyl 400 mg Tablet safer than Secnidazole for treating amoebiasis and giardiasis?

Drug - Drug interaction

1. Alcohol

• Interaction: Combining metronidazole with alcohol can cause a reaction including nausea, vomiting, flushing, rapid heartbeat, and headach
• Management: Avoid alcohol and products containing alcohol during treatment and for at least 48 hours after the last dose.

2. Warfarin and Other Oral Anticoagulants

• Interaction: May increase the anticoagulant effects and bleeding risk by interfering with warfarin metabolism
• Management: Monitor blood clotting parameters (INR/PT) closely. Dosage adjustments to warfarin may be needed by your doctor.

3. Lithium

• Interaction: Metronidazole can elevate lithium levels, leading to toxicity that may harm kidneys and nervous system
• Management: Check blood lithium levels regularly if used together; dose reduction or stopping lithium may be required. Watch for signs like tremor, confusion, or unsteadiness.

4. Disulfiram

• Interaction: Combined use may cause confusion or psychotic reactions
• Management: Do not use together. If both are necessary, allow at least two weeks between stopping one and starting the other.

5. Antiepileptics (Phenytoin, Phenobarbital, Carbamazepine)

• Interaction: These drugs can lower blood levels and effectiveness of metronidazole, or vice versa
• Management: Monitor for reduced efficacy or increased side effects; your doctor may adjust doses as needed. Notify your provider if seizure control changes.

6. Oral Contraceptives

• Interaction: Effectiveness of hormonal birth control may be decreased by metronidazole
• Management: Use additional contraceptive methods (such as condoms) during metronidazole therapy and for at least a week after finishing.

7. Busulfan

• Interaction: May increase toxicity (especially bone marrow suppression) of busulfan
• Management: Avoid combination where possible; otherwise, monitor blood counts closely.

8. Ciclosporin

• Interaction: Increases levels of ciclosporin, raising the risk of toxicity
• Management: Monitor ciclosporin blood levels and kidney function; dose adjustment may be needed.

9. Certain Antibiotics/Antifungals/Antiarrhythmics/Antipsychotics (e.g., ciprofloxacin, clarithromycin, ketoconazole, amiodarone, pimozide)

• Interaction: Risk of heart rhythm disturbances (QT prolongation)
• Management: If co-administration is necessary, monitor heart rhythm (ECG) and watch for symptoms such as irregular heartbeat, fainting, or dizziness.

Drug - Food interaction

1. Alcohol

• Interaction: Consuming alcohol with metronidazole can cause a severe reaction—symptoms may include flushing, nausea, vomiting, abdominal cramps, rapid heartbeat, and headache. This is sometimes called a “disulfiram-like reaction.”
• Management: Strictly avoid alcohol (including alcoholic beverages, mouthwashes, and syrups) during treatment and for at least 48 hours after the last dose. Read all product labels for hidden alcohol sources.

2. Dairy and Calcium-rich Foods

• Interaction: Unlike some antibiotics, metronidazole absorption is not significantly affected by dairy products or foods high in calcium.
• Management: No special restrictions are needed for milk or calcium; you may take Metrogyl 400 with or without dairy.

3. Food in General (Meals)

• Interaction: Taking metronidazole on an empty stomach may increase the risk of stomach upset, nausea, or metallic taste.
• Management: To minimize side effects, take the tablet with or after food and a full glass of water. This also helps with regular absorption and reduces digestive discomfort.

4. Tyramine-rich Foods (e.g., aged cheese, cured meats, fermented products)

• Interaction: Metronidazole rarely interacts with tyramine, but in very sensitive individuals, combining the two could possibly increase blood pressure or risk of headache.
• Management: No routine restrictions, but if you wear a pacemaker or have severe hypertension, inform your doctor and moderate very high intake of tyramine-rich foods.

5. Caffeinated Drinks

• Interaction: Caffeine clearance from the body may be slightly slowed by metronidazole, leading to prolonged caffeine effects in some people.
• Management: Limit excess caffeine (coffee, energy drinks) if you notice restlessness, jitteriness, or sleep disturbances during therapy.

Synopsis

FAQs About METROGYL 400 TABLET

References

1. KD. Tripathi. Macrolide and other antibacterial antibiotics. Anti-amoebic and other antiprotozoal drugs. Essentials of Medical Pharmacology. 7th Edition. Page – 763 & 837.

2. Weir CB, JK. Metronidazole. StatPearls. NIH. National Library of Medicine. National Center for Biotechnology Information. PMC. PubMed Central. June 2022. [Accessed on 26th July 2025]. 

3. Rx Farma Limited. Metronidazole 200, 400 and 500mg Tablets. Electronic Medicines Compendium. [Revised in August 2019]. [Accessed on 26th July 2025]. 

4. Milpharm Limited. Metronidazole 200 and 400mg Tablets. Electronic Medicines Compendium. [Revised in September 2021]. [Accessed on 26th July 2025]. 

5. Central Drugs Standard Control Organization. Metronidazole 250mg (Oral). March 1961. [Accessed on 26th July 2025]. 

Useful Diagnostic Tests

• Liver Function Test
• Complete Blood Count

Author Details

Written By Dr. Karthikeyan Rajagopal - M.Pharm (Pharmacology)

Reviewed For Accuracy By Dr. Salem Gill - MBBS

Last updated on 29 Jul 2025 | 10:55 AM(IST)