Medetomidine

Medetomidine	Last updated: 15/09/2025
(Not known by any other names)

GENERAL INFORMATION

Description

Medetomidine is a veterinary sedative analgesic often used in combination with opioids and used as the hydrochloride salt.

Examples of veterinary uses

Used as both a surgical anesthetic and an analgesic

Examples of species treated

Deer; Cats; Dogs

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved - usually available as a prescription-only-medicine to be authorised by a veterinarian (POM-V)

EU Regulatory approval status

Approved

Chemical structure

Isomerism

Medetomidine exhibits optical isomerism, meaning it exists as two enantiomers: dexmedetomidine and levomedetomidine. These enantiomers differ in the spatial arrangement around a chiral centre, which significantly affects their biological activity. The dex- isomer is the pharmacologically active form, it binds selectively to alpha2-adrenergic receptors, producing sedation, analgesia, and anxiolysis. In contrast, levomedetomidine has minimal clinical effect and is generally considered inactive. Commercial medetomidine used in veterinary medicine is typically a racemic mixture, containing equal parts of both enantiomers. However, in human medicine, dexmedetomidine alone is preferred for its targeted action and reduced side effects.

Chemical formula

C₁₃H₁₆N₂

Canonical SMILES

CC1=C(C(=CC=C1)C(C)C2=CN=CN2)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

CUHVIMMYOGQXCV-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C13H16N2/c1-9-5-4-6-12(10(9)2)11(3)13-7-14-8-15-13/h4-8,11H,1-3H3,(H,14,15)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
medetomidine hydrochloride	Variant

General status

Veterinary substance type

Sedative, Analgesic

Other bioactivity & uses

Biocide; Antifouling agent

Substance groups

Unclassified substance

Minimum active substance purity

>99%

Known relevant impurities

Substance origin

Synthetic

Mode of action

A non-narcotic alpha2-adrenoreceptor agonist

Molecular targets

[Alpha2-adrenergic, Agonist]

CAS RN

86347-14-0

EC number

811-718-6

CIPAC number

None allocated

US EPA chemical code

PubChem CID

69602

CLP index number

No data found

Therapeutic Class

Nervous system: Psycholeptics

ATCvet Code

QN05CM91

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

200.28

PIN (Preferred Identification Name)

IUPAC name

(RS)-4-[1-(2,3-dimethylphenyl)ethyl]-3H-imidazole

CAS name

Forever chemical

Other status information

EU approval as antifouling agent until June 2026

Relevant Environmental Water Quality Standards

Physical state

White crystalline, odourless powder

Related substances & organisms

detomidine

detomidine hydrochloride

dexmedetomidine

medetomidine hydrochloride

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1990s, developed & registered

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

I-Tech AB Sweden
Forte Healthcare UK
VetPharma Spain
HomeLab Veterinary

Example products using this active

Selekope
Sededorm
Domior
Sedatyt
Madis
Prosed

Formulation and application details

Usually formulated as injectable solutions

Commercial production

Medetomidine is synthesised through a multi-step organic process that typically begins with the preparation of a substituted imidazole derivative. One efficient route involves a nucleophilic addition reaction between 1-trityl imidazole-4-formaldehyde and 2,3-dimethylphenylmagnesium bromide to form a key intermediate. This is followed by a Wittig olefination step to introduce an alkenyl group, which is then subjected to hydrogenation to yield racemic medetomidine. The final product may be purified and resolved into its enantiomers, most notably dexmedetomidine, using chiral separation techniques such as crystallisation with (+)-tartaric acid.

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)

19800

High

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

3300

p-Xylene

65000

Acetone

Melting point (°C)

116

Boiling point (°C)

382

Degradation point (°C)

Flashpoint (°C)

191.3

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

7.94 X 10⁰²

Calculated

Log P

2.9

Moderate

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

3.5 X 10^-03

Low volatility

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

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

100

Persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Literature: Slow degradation

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)

110

Slow

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)

Slightly mobile

K_oc (mL g⁻¹)

2460

Notes and range

Literature data range K_oc 1215 to 3705 g/mL

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

1.22

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 31.25

Rat

High

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)

30.0

Danio rerio

Moderate

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

4.5

Moderate

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)

0.005

Americamysis bahia as 28 day NOEC

High

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) (EC₅₀)

0.34

Desmodesmus subspicatus

Moderate

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)

> 31.25

Rat

High

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.14

Rat 4 hr

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

Metabolised and excreted via the kidneys in the urine.

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

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

Possible lungs, liver and kidney toxicant
May cause hypersensitivity reactions
Harmful if swallowed
Has a strong sedative effect

Handling issues

Property

Value and interpretation

General

Emits a variety of toxic fumes on combustion
Corrosive
Not explosive or oxidising

CLP classification 2013

Health: H300, H310
Environment: H400, H410

WHO Classification

Not listed (Not listed)

UN Number

Not regulated

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

medetomidine

French

German

Danish

Italian

Spanish

medetomidina

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	15/09/2025
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