Detomidine
Imidazoline derivative alpha2-adrenergic agonist
Also known as: Dormosedan · demotidini hydrochloridum · MPV 253-AII
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Reviewed non-calculator evidenceReviewed non-calculator evidence (1)
Evidence only — not for automatic calculation
Injection
• Injection: Detomidine 0.02 – 0.04 mg/kg IV or IM; allow animal to rest quietly prior to and after injection. Effects generally occur within 2 to 4 minutes of administration. Lower dose will generally provide 30 to 90 minutes of sedation. The higher dose will generally provide 90 to 120 minutes of sedation.
Governing clinical context (3)
- CAUTION: Do not confuse µg/kg or mg/m 2 with mg/kg doses.
- Detomidine HCl for injection should be stored at room temperature, 15°C to 30°C (59°F-85°F) and protected from light.
- Detomidine gel for sublingual administration should be stored at controlled room temperature, 20°C to 25°C (68°F-77°F); excursions are permitted from 15°C to 30°C (59°F-85°F).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Detomidine is a potent alpha-2 adrenergic agonist used primarily in equine medicine for its profound sedative and analgesic properties.
- Potency: It is approximately 50 to 100 times more potent than xylazine.
- Clinical Use: Widely used for standing sedation, minor surgical procedures, and analgesia (especially for colic) in horses. It has also been used off-label in cattle, small ruminants, camelids, and birds.
- Important Caveat: Even when horses appear deeply sedated, they may still respond suddenly to external stimuli (e.g., kicking). The addition of an opioid (like butorphanol) can help temper this startle response and improve the quality of sedation.
Mechanism of action
Detomidine acts as a potent and highly specific agonist at alpha-2 adrenergic receptors in the central and peripheral nervous systems.
- Sedation & Analgesia: Activation of presynaptic alpha-2 receptors in the locus coeruleus and dorsal horn of the spinal cord → inhibition of norepinephrine release → decreased sympathetic outflow, resulting in profound sedation, muscle relaxation, and analgesia.
- Cardiovascular Effects: Initial activation of peripheral postsynaptic alpha-2 receptors → transient vasoconstriction and hypertension → compensatory vagal reflex → profound bradycardia and potential AV block. Central sympatholytic effects then lead to a prolonged decrease in blood pressure.
Safety & warnings
Contraindications
- Preexisting AV or SA heart block
- Severe coronary insufficiency
- Cerebrovascular disease
- Severe respiratory disease
- Chronic renal failure
Adverse effects
- Initial blood pressure increase (hypertension)
- Profound bradycardia and heart block (AV block)
- Piloerection
- Sweating
- Ataxia
- Salivation
- Slight muscle tremors
- Penile prolapse
- Decreased gastrointestinal motility
Precautions
Clinical Precautions:
- Shock & Organ Dysfunction: Use cautiously in animals with endotoxic/traumatic shock, or advanced hepatic/renal disease.
- Stress Factors: Administer carefully to horses stressed by temperature extremes, fatigue, or high altitude. Consider lower doses in summer heat.
- Gastrointestinal: Inhibits GI motility; use with prudence in patients treated for intestinal impactions. May mask abdominal pain in colic cases, complicating diagnosis.
- Safety: Wear impermeable gloves when administering the sublingual gel to avoid human exposure.
Drug interactions
Not recommended to be used together as effects may be additive.
Effects may be additive; dosage reduction required. Increased risk for arrhythmias with thiopental, ketamine, or halothane.
Do not use to treat cardiac effects caused by detomidine, as epinephrine possesses alpha agonist effects.
Severe hypotension can result.
Fatal dysrhythmias may occur if used with intravenous potentiated sulfonamides.
Monitoring
- Level of sedation and analgesia
- Cardiac rate and rhythm
- Blood pressure (if indicated)
Pharmacokinetics
Half-life
Absorption
Well absorbed after oral administration, but currently used primarily parenterally. Oromucosal gel bioavailability is 22% vs 38% for IM.
Distribution
Rapidly distributed into tissues, including the brain. Volume of distribution in horses: 0.47-0.59 L/kg (at rest), 1.3 L/kg (after exercise).
Metabolism
Extensively metabolized.
Elimination
Excreted primarily into the urine. Clearance: 12-16 mL/min/kg.
Overdose
Toxicity Profile:
- Tolerated by horses at 5X the high dose level (0.2 mg/kg).
- Doses of 10-40X recommended can cause severe respiratory and cardiovascular changes that can become irreversible and cause death.
- Reversal: Alpha-2 antagonists such as atipamezole (50-100 micrograms/kg) or yohimbine can be successfully used to reverse some or all effects of inadvertent overdoses.
Available products
Formulations
- Injection (10 mg/mL)
- Oromucosal Sublingual Gel (7.8 mg/mL)
Veterinary
- Detomidine HCl for Injection: 10 mg/mL (Dormosedan)
- Detomidine HCL Oromucosal Gel: 7.8 mg/mL (Dormosedan Gel)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Injection should be stored at room temperature (59-85°F; 15-30°C) and protected from light. Gel should be stored at controlled room temperature (68-77°F; 20-25°C).
Client information
Important Guidance for Owners:
- This drug is a potent sedative and should only be used in a professionally supervised setting by individuals familiar with its properties.
- Even if your horse appears deeply asleep, they can still react suddenly and kick if startled by loud noises or touch. Always approach sedated horses with caution.
- If using the oral gel at home under veterinary direction, wear impermeable gloves to prevent the drug from absorbing through your skin.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.