Dimetridazole

Dimetridazole	Last updated: 16/09/2025
(Also known as: DMZ)

GENERAL INFORMATION

Description

An anti-fungal and anti-protozoal substance used for the control of infection, mostly in birds

Examples of veterinary uses

Mainly used to manage diarrhea, inflammatory bowel disease and general infections

Examples of species treated

Pigs; Game birds; Pigeons; Caged birds

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

None

Chemical formula

C₅H₇N₃O₂

Canonical SMILES

CC1=NC=C(N1C)[N+](=O)[O-]

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

IBXPYPUJPLLOIN-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C5H7N3O2/c1-4-6-3-5(7(4)2)8(9)10/h3H,1-2H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
dimetridazole	-

General status

Veterinary substance type

Antiparasitic, Bactericide, Fungicide, Coccidiostat, Feed additive

Substance groups

Nitroimidazole

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Works by targeting DNA, where it undergoes reductive activation inside anaerobic organisms. Once activated, dimetridazole forms reactive intermediates that bind to DNA, causing strand breaks and inhibition of nucleic acid synthesis, ultimately leading to cell death

Molecular targets

[DNA, Reductive activation]

CAS RN

551-92-8

EC number

209-001-2

CIPAC number

US EPA chemical code

371200

PubChem CID

Therapeutic Class

Antiparasitic products, insecticides & repellents: Agents against protozoal diseases

ATCvet Code

QP51AA07

Controlled Drug?

Regulation 37/2010 MRL Classification

Prohibited

Molecular mass

141.13

PIN (Preferred Identification Name)

IUPAC name

1,2-dimethyl-5-nitroimidazole

CAS name

1,2-dimethyl-5-nitro-1H-imidazole

Forever chemical

Other status information

Evidence of use in third world countries; Not approved as a feed additive in EU

Relevant Environmental Water Quality Standards

Physical state

White to pale-yellow crystalline powder

Commercial

Property

Value

Availability status

Banned in many countries

Introduction & key dates

Circa 1955, first synthesis; 1990, first EU listing; 2010s, banned Canada, EU & USA

Example manufacturers & suppliers of products using this active now or historically

Merial Animal Health Ltd

Example products using this active

Emtryl Premix
Emtryl Pure
Emtryl Soluble

Formulation and application details

Usually administered as a feed or water additive

Commercial production

Dimetridazole is synthesised through a multi-step chemical process starting with 2-methyl-5-nitroimidazole as the key intermediate. In one common method, this compound is reacted with dimethyl sulphate in the presence of formic acid. After the reaction, the formic acid is removed via vacuum distillation, and the residue is dissolved in water and neutralised using aqueous ammonia. Cooling the solution to near 0 DegC allows unreacted material to precipitate and be removed. The remaining solution is then adjusted to a basic pH, which facilitates the isolation of dimetridazole.

Impact on climate of production and use

Published GHG data is not available for most pharmaceuticals. However, according to industry, global averages suggest producing 1 kg of a typical active pharmaceutical ingredient can range from 10 to 100 kg CO₂e for small molecule drugs and potentially up to 1000 kg CO₂e for complex biologicals such as vaccines, depending on the drug type, its formulation, complexity of synthesis, solvent recovery, and energy sources used.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

18300

High

Solubility - In organic solvents at 20 °C (mg l⁻¹)

Melting point (°C)

322

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

2.04 X 10⁰⁰

Calculated

Log P

0.31

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.426

Dissociation constant pKa) at 25 °C

2.6

Vapour pressure at 20 °C (mPa)

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Surface tension (mN m⁻¹)

Refractive Index

Environmental release

Substance may enter the environment via the faeces of treated animals or by leaching from spilt medicated feed.

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Sediment phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

2-hydroxymethyl-1-methyl-5-nitroimidazole

HMMNI

Animal (Urine); Turkeys (Tissue)

1-methyl-5-nitroimidazol-2-yl methyl hydrogen sulphate

Turkeys (Tissue)

1-methyl-5-nitroimidazol-2-yl methyl carboxylic acid

MNICA

Turkeys (Tissue)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1600

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Notes

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹)

Algae - Chronic (growth rate, fresh; mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1600

Rat

Moderate

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Mammalian dose elimination route and rate

Extensively metabolised and excreted in the urine, faeces and in expired air

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

No data found

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Inhalation may cause haemorrhage in lungs and cervical lymph nodes

Handling issues

Property

Value and interpretation

General

IMDG Transport Hazard Class 9

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

dimetridazole

French

German

Danish

Italian

Spanish

dimetridazol

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	16/09/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242