metronidazole

CHEBI:6909 ·resolve ·ANTIBACTERIAL ·EXACT SEEDED

A member of the class of imidazoles substituted at C-1, -2 and -5 with 2-hydroxyethyl, nitro and methyl groups respectively. It has activity against anaerobic bacteria and protozoa, and has a radiosensitising effect on hypoxic tumour cells. It may be given by mouth in tablets, or as the benzoate in an oral suspension. The hydrochloride salt can be used in intravenous infusions. Metronidazole is a prodrug and is selective for anaerobic bacteria due to their ability to intracellularly reduce the nitro group of metronidazole to give nitroso-containing intermediates. These can covalently bind to DNA, disrupting its helical structure, inducing DNA strand breaks and inhibiting bacterial nucleic acid synthesis, ultimately resulting in bacterial cell death. — ChEBI

Machine-generated and unreviewed. Identity, structure and cross-references come straight from ChEBI's and CARD's own data; no curator has signed off on this record yet.

Classification

nitroimidazole antibioticARO:3004115

Strictly broader compounds or drug classes this molecule belongs to.

CHEBI:15734 CHEBI:15734
CHEBI:24780 CHEBI:24780
CHEBI:35716 CHEBI:35716
ARO:3004115 ARO:3004115

Chemical structure

Computed structure properties
Molecular formula	C6H9N3O3
Charge	0
Average mass	171.156 Da
Monoisotopic mass	171.06439 Da
Source	ChEBI
InChIKey	VAOCPAMSLUNLGC-UHFFFAOYSA-N

SMILES

Cc1ncc([N+](=O)[O-])n1CCO

InChI

InChI=1S/C6H9N3O3/c1-5-7-4-6(9(11)12)8(5)2-3-10/h4,10H,2-3H2,1H3

Also called

metronidazol (INN)— chebi
metronidazolum (INN)— chebi
métronidazole (INN)— chebi
2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethanol (EXACT_SYNONYM)— chebi
1-(2-hydroxy-1-ethyl)-2-methyl-5-nitroimidazole (EXACT_SYNONYM)— chebi
1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole (EXACT_SYNONYM)— chebi
1-(β-ethylol)-2-methyl-5-nitro-3-azapyrrole (EXACT_SYNONYM)— chebi
1-(β-hydroxyethyl)-2-methyl-5-nitroimidazole (EXACT_SYNONYM)— chebi
1-(β-oxyethyl)-2-methyl-5-nitroimidazole (EXACT_SYNONYM)— chebi
2-methyl-1-(2-hydroxyethyl)-5-nitroimidazole (EXACT_SYNONYM)— chebi
2-methyl-3-(2-hydroxyethyl)-4-nitroimidazole (EXACT_SYNONYM)— chebi
2-methyl-5-nitroimidazole-1-ethanol (EXACT_SYNONYM)— chebi
Flagyl (EXACT_SYNONYM)— aro

Cross-references

Equivalent identifiers for this same structure in other resources.

ARO:3000689
cas:443-48-1
drugbank:DB00916
drugcentral:1790
hmdb:HMDB0015052
kegg.drug:D00409
lincs.smallmolecule:LSM-5628
patent:US2944061
pdb-ccd:2MN
reaxys:611683
vsdb:1826
wikipedia.en:Metronidazole
chembl:CHEMBL137
pubchem.compound:4173

Activity roles

Every antimicrobial role a source asserts for this compound — the unreduced evidence behind its antimicrobial_class.

CHEBI:33281 CHEBI:33281
CHEBI:36047 CHEBI:36047
CHEBI:50685 CHEBI:50685

Source concepts

Every upstream concept that resolved to this record. The merge is the product: this is what shows ChEBI and CARD are describing the same structure.

Upstream concepts merged into this record
Source	Native ID	Label	Minted CURIE	Version
ARO	`ARO:3000689`	metronidazole	`antibioticmech:aro-a369adefb4`	2026-08-30
CHEBI	`CHEBI:6909`	metronidazole	`antibioticmech:chebi-daf94f3c73`	2026-08-30

Molecular targets

The molecular entity or process this compound acts on. Each target carries evidence — this is a mechanistic claim, not a classification.

anaerobe DNA NUCLEIC_ACID ATTACKED_COMPONENT

ARO:3000742

CARD/ARO database assertion; target organism, strain, and assay are not specified. Activated nitroimidazole intermediates attack DNA in anaerobic context. Evidence status: DATABASE_ASSERTION_ONLY. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

ARO:3000742 (CARD/ARO asserts targeted_by_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)

Mechanism summary

Clinical status: APPROVED

Resistance mechanisms

18 known routes by which microbes resist this compound, grounded in ARO where CARD models them. Grouped by mechanism type — expand a group to see its determinants.

ANTIBIOTIC_INACTIVATION 12

ANTIBIOTIC_INACTIVATION
Determinant	ARO ID	Organism	Gene families	Evidence
Clostridioides difficile nimB	ARO:3007671	not organism-specific	—	ARO:3007671 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimA	ARO:3007104	not organism-specific	—	ARO:3007104 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimB	ARO:3004655	not organism-specific	—	ARO:3004655 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimC	ARO:3007105	not organism-specific	—	ARO:3007105 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimD	ARO:3007106	not organism-specific	—	ARO:3007106 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimE	ARO:3007107	not organism-specific	—	ARO:3007107 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimF	ARO:3007108	not organism-specific	—	ARO:3007108 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimG	ARO:3007109	not organism-specific	—	ARO:3007109 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimH	ARO:3007110	not organism-specific	—	ARO:3007110 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimI	ARO:3007111	not organism-specific	—	ARO:3007111 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimJ	ARO:3007112	not organism-specific	—	ARO:3007112 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
nimK	ARO:3007113	not organism-specific	—	ARO:3007113 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)

ANTIBIOTIC_EFFLUX 3

ANTIBIOTIC_EFFLUX
Determinant	ARO ID	Organism	Gene families	Evidence
hp1181	ARO:3003964	not organism-specific	—	ARO:3003964 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
hp1184	ARO:3003965	not organism-specific	—	ARO:3003965 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
msbA	ARO:3003950	not organism-specific	—	ARO:3003950 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)

ANTIBIOTIC_TARGET_ALTERATION 3

ANTIBIOTIC_TARGET_ALTERATION
Determinant	ARO ID	Organism	Gene families	Evidence
Antibiotic resistant Helicobacter pylori nitroreductase	ARO:3007056	not organism-specific	—	ARO:3007056 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
Helicobacter pylori frxA mutation conferring resistance to metronidazole	ARO:3007059	not organism-specific	—	ARO:3007059 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)
Helicobacter pylori rdxA mutation conferring resistance to metronidazole	ARO:3007055	not organism-specific	—	ARO:3007055 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000689 (metronidazole); database assertion, not a primary citation.)

Curation history

SEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Seeded from data/raw/ inventories (ARO, CHEBI)
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories

Provenance

Seeded by scripts/seed_from_sources.py from the committed inventories in data/raw/. View the record.