Flagyl, Metrogyl
Generic Name
metronidazole
Manufacturer
Various manufacturers globally
Country
Global
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Description
Overview of the medicine
Metronidazole is an antibiotic and antiprotozoal medication used to treat a wide variety of infections, including amoebiasis, giardiasis, trichomoniasis, bacterial vaginosis, and infections caused by anaerobic bacteria.
Uses & Indications
Dosage
Adults
Typical oral dosage ranges from 250 mg to 750 mg, 2-3 times daily, depending on the indication. Treatment duration varies (e.g., 5-10 days for amoebiasis, single dose for trichomoniasis).
Elderly
No specific dose adjustment recommended, but caution advised due to potential for reduced hepatic/renal function.
Renal_impairment
Dosage adjustment may be necessary in severe renal impairment (e.g., reduce dose by 50% for CrCl < 10 ml/min).
How to Take
Oral tablets/suspension can be taken with or without food. To minimize gastric upset, it's often recommended with food. Complete the full course of treatment.
Mechanism of Action
It enters the bacterial or protozoal cell, where its nitro group is reduced, forming reactive cytotoxic compounds that damage DNA and other macromolecules, leading to cell death.
Pharmacokinetics
Onset
Onset of action varies by route and indication; typically within hours for oral forms.
Excretion
Mainly excreted in urine (60-80%) as unchanged drug and metabolites; some fecal excretion.
Half life
Approximately 8 hours (range 6 to 12 hours) in adults.
Absorption
Rapidly and almost completely absorbed from the gastrointestinal tract after oral administration.
Metabolism
Primarily hepatic metabolism via oxidation and glucuronide conjugation.
Side Effects
Contraindications
- Hypersensitivity to metronidazole or other nitroimidazole derivatives.
- First trimester of pregnancy (relative contraindication, generally avoided).
- Concomitant use of disulfiram within the last 14 days.
Drug Interactions
Alcohol
Disulfiram-like reaction (nausea, vomiting, flushing, tachycardia). Avoid alcohol during treatment and for at least 3 days after.
Lithium
Increases serum lithium levels, potentially leading to toxicity.
Warfarin
Potentiates anticoagulant effect, increasing bleeding risk. Monitor INR closely.
Disulfiram
Psychotic reactions; do not administer within 14 days of each other.
Phenytoin/Phenobarbital
May decrease metronidazole plasma levels.
Storage
Store below 30°C in a dry place, away from light and moisture. Do not freeze oral suspensions.
Overdose
Symptoms of overdose include nausea, vomiting, ataxia, and mild disorientation. Treatment is symptomatic and supportive. There is no specific antidote.
Pregnancy & Lactation
Generally avoided in the first trimester of pregnancy; use with caution in second and third trimesters only if clearly needed. Metronidazole is excreted into breast milk; breastfeeding should be temporarily discontinued during therapy and for 12-24 hours after the last dose.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
Typically 2 to 3 years from the date of manufacture, specific to product formulation.
Availability
Available in pharmacies, hospitals and clinics
Approval Status
FDA and DGDA approved
Patent Status
Off-patent
WHO Essential Medicine
YesClinical Trials
Metronidazole has been extensively studied since its introduction, with ongoing clinical trials investigating new indications, formulations, and resistance patterns. Many studies confirm its efficacy against anaerobic bacteria and various protozoal infections.
Lab Monitoring
- Regular monitoring of white blood cell counts, especially with prolonged use or repeated courses.
- Liver function tests may be considered in patients with hepatic impairment.
Doctor Notes
- Advise patients to avoid alcohol during and for at least 3 days after metronidazole therapy due to disulfiram-like reactions.
- Monitor for signs of peripheral neuropathy or central nervous system effects, especially with prolonged courses.
- Caution in patients with severe hepatic impairment, dosage adjustment may be needed.
Patient Guidelines
- Take the medicine exactly as prescribed by your doctor.
- Do not stop taking metronidazole even if you feel better; complete the full course of treatment to prevent recurrence.
- Avoid alcohol completely during treatment and for at least 3 days after.
Missed Dose Advice
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one.
Driving Precautions
Metronidazole may cause dizziness, drowsiness, or visual disturbances in some patients. If these symptoms occur, avoid driving or operating heavy machinery.
Lifestyle Advice
- Maintain good hygiene to prevent reinfection, especially in sexually transmitted infections.
- Stay hydrated by drinking plenty of fluids.
- Report any unusual or severe side effects to your doctor immediately.
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Global Brand Names
International brand names for this medicine. Click a brand to search for detailed information.