Product Information

Registration Status: Active

FLAGYL TABLET 200mg is approved to be sold in Singapore with effective from 1988-06-30. It is marketed by SANOFI-AVENTIS SINGAPORE PTE LTD, with the registration number of SIN02201P.

This product contains Metronidazole 200mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.

This product is manufactured by Famar Health Care Services Madrid in SPAIN.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.



A nitroimidazole used to treat amebiasis; vaginitis; trichomonas infections; giardiasis; anaerobic bacteria; and treponemal infections. It has also been proposed as a radiation sensitizer for hypoxic cells. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985, p133), this substance may reasonably be anticipated to be a carcinogen (Merck, 11th ed).


For the treatment of anaerobic infections and mixed infections, surgical prophylaxis requiring anaerobic coverage, Clostridium difficile-associated diarrhea and colitis, Helicobacter pylori infection and duodenal ulcer disease, bacterial vaginosis, Giardia lamblia gastro-enteritis, amebiasis caused by Entamoeba histolytica, acne rosacea (topical treatment), and Trichomonas infections.

Mechanism of Action

Metronidazole is a prodrug. Unionized metronidazole is selective for anaerobic bacteria due to their ability to intracellularly reduce metronidazole to its active form. This reduced metronidazole then covalently binds to DNA, disrupt its helical structure, inhibiting bacterial nucleic acid synthesis and resulting in bacterial cell death.


Well absorbed (at least 80%) with peak plasma concentrations achieved in 1-3 hours following oral administration of therapeutic doses of immediate release formulation.
Hepatic metabolism by hydroxylation, oxidation, and glucuronidation.


LD50=500 mg/kg/day (orally in rat). Adverse effects include reversible peripheral neuropathy with prolonged therapy, CNS toxicity, disulfiram effect with alcohol, dark red-brown urine, metallic taste, nausea, epigastric distress, dizziness, vertigo and paresthesias associated with high doses, and neutropenia (reversible and mild).

Active Ingredient/Synonyms

1-(2-hydroxy-1-ethyl)-2-methyl-5-nitroimidazole | 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole | 1-(beta-Ethylol)-2-methyl-5-nitro-3-azapyrrole | 1-(beta-Hydroxyethyl)-2-methyl-5-nitroimidazole | 1-(beta-Oxyethyl)-2-methyl-5-nitroimidazole | 1-(β-ethylol)-2-methyl-5-nitro-3-azapyrrole | 1-(β-hydroxyethyl)-2-methyl-5-nitroimidazole | 1-(β-oxyethyl)-2-methyl-5-nitroimidazole | 2-methyl-1-(2-hydroxyethyl)-5-nitroimidazole | 2-methyl-3-(2-hydroxyethyl)-4-nitroimidazole | 2-methyl-5-nitroimidazole-1-ethanol | Metronidazol | Metronidazolum | Metronidazole |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank