Medetomidine: veterinary dose and monograph

At a glance

Drug class

Sedative / anaesthetic

Also known as

Domitor, Medetomidine hydrochloride

Species with doses

Dogs, Cats, Horses, Sheep, Birds, Rabbits, Ferrets, Guinea pigs, Reptiles, Rats, Hedgehogs, Primates and Big cats

General dose range

0.01–0.04 mg/kg IM single dose (reversible) — check the species tables for the indication

Routes

IM, IV

Last reviewed

1 October 2026

Indications

• Sedation and restraint for examination, imaging and minor procedures
• Premedication / part of balanced anaesthesia (opioid-sparing, anaesthetic-sparing)
• Short-term analgesia
• Reversible chemical restraint (with atipamezole reversal)

Medetomidine dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Sedation / premed: Plumb’s p.765: 10–40 µg/kg IM (higher doses prolong rather than deepen sedation; McGrath & Ko 1997); 5–10 µg/kg with an IM opioid (Hardie 2000). Papich 5e: 1000 µg/m² IM or 750 µg/m² IV; 5–15 µg/kg IV, IM or SC for short sedation/analgesia (up to 60 µg/kg for severe pain); 20 µg/kg with butorphanol, hydromorphone or ketamine. Reverse with atipamezole (5× the medetomidine dose, equal volume).
• Analgesic CRI (cardiovascularly stable): Plumb’s p.765 (Quandt 2009): 1 µg/kg IV then 1–3 µg/kg/h. Papich 5e: 1 µg/kg then 1.5 µg/kg/h — monitor for cardiovascular effects.

Cats

• Sedation / restraint: Plumb’s p.765: 40–80 µg/kg IM (McGrath & Ko 1997); 5–10 µg/kg with an IM opioid (Hardie); 1–10 µg/kg IV, IM or SC (Carroll 1999). Papich 5e: 10–20 µg/kg for short sedation/analgesia, up to 80 µg/kg for severe pain; with ketamine 5 mg/kg + medetomidine 5 µg/kg IM. Vomiting common. Reverse with atipamezole.

Horses

• Pre-induction sedation: Papich 5e: 10 µg/kg IM before induction; some horses need an additional 4 µg/kg IV; used with guaifenesin 5% and ketamine 2.2 mg/kg.

Sheep

• Sedation (lambs): Papich 5e: lambs 30 µg/kg IV. Alpha-2 agonists can cause hypoxaemia and pulmonary oedema in sheep — oxygen and monitoring. Extra-label — obtain a FARAD withdrawal.

Birds

• Sedation: Plumb's p.766 (Clyde & Paul-Murphy 2000): 0.1 mg/kg IM; limited data — usually combined with ketamine.

Rabbits

• Sedation / anaesthesia (with ketamine): Plumb's p.766 (Burke 1999): rabbits 0.25–0.5 mg/kg IM, usually combined with ketamine. Reverse with atipamezole.

Ferrets

• Sedation / injectable anaesthesia: Plumb's p.766: 60–80 µg/kg IM/SC — pre-treat with atropine 0.05 mg/kg or glycopyrrolate 0.01 mg/kg 15 min prior. Anaesthesia combo: medetomidine 80 µg/kg + ketamine 5 mg/kg + butorphanol 0.1 mg/kg IM. Reverse with atipamezole.

Guinea pigs

• Sedation / anaesthesia: Plumb's p.765 (Burke 1999): guinea pig 0.5 mg/kg IM (with ketamine).

Reptiles

• Immobilisation (with ketamine): Plumb's p.766: chelonians — small/medium tortoises 100–150 µg/kg + ketamine 5–10 mg/kg; freshwater turtles 150–300 µg/kg + ketamine 10–20 mg/kg; giant Aldabra tortoises 40–80 µg/kg + ketamine 4–8 mg/kg; iguanas 100–150 µg/kg + ketamine 5–10 mg/kg. Wait 30–40 min for peak. (40–300 µg/kg = 0.04–0.3 mg/kg.)

Rats

• Sedation / anaesthesia: Plumb's p.765 (Burke 1999): rats 0.25–0.5 mg/kg IM (with ketamine).

Hedgehogs

• Sedation (± ketamine): Carpenter Exotic Animal Formulary 6th ed, Table 8-4 (p.516): hedgehogs 0.05–0.1 mg/kg IM for light sedation, 0.2 mg/kg SC for heavy sedation; often ketamine 5 mg/kg + medetomidine 0.1 mg/kg IM. Reverse with atipamezole 0.3–0.5 mg/kg IM.

Primates

• Sedation (monkeys — with ketamine): Carpenter Exotic Animal Formulary 6th ed, Table 13-4 (p.697): monkeys 0.01–0.035 mg/kg IM; squirrel monkeys/baboons 0.1 mg/kg SC/IM; macaques 0.15 mg/kg IM. Now largely replaced by dexmedetomidine (½ dose). Combine with ketamine; reverse with atipamezole.

Big cats

• Immobilisation (tigers/large felids): Plumb's p.765 (Curro 2002): midazolam 0.1 mg/kg + medetomidine 0.05–0.07 mg/kg IM, then ketamine 4–10 mg/kg IM if needed. Reverse medetomidine with atipamezole 0.25–0.35 mg/kg IV/SC.

Contraindications

Cardiovascular disease (significant bradyarrhythmia, AV block), shock/hypovolaemia, hepatic or renal impairment, respiratory disease, diabetes (transient hyperglycaemia), and severely debilitated or very young/old patients. Caesarean/late pregnancy (uterine effects, fetal depression). Known hypersensitivity.

Species-specific warnings

Cats: Vomiting is common after dosing; combine carefully and avoid in cats with significant cardiac or systemic disease.

Dogs: Profound bradycardia/reduced cardiac output — avoid in dogs with cardiovascular disease, shock or debilitation.

Adverse effects

• Marked bradycardia and AV block; initial hypertension then hypotension
• Reduced cardiac output (up to ~50 %), vasoconstriction (pale mucosae)
• Respiratory depression
• Vomiting (especially cats), hyperglycaemia and diuresis
• Muscle twitching; rare paradoxical excitation

Drug interactions

• Other CNS depressants/anaesthetics: marked additive sedation/cardiorespiratory depression — reduce co-drug doses
• Anticholinergics (atropine/glycopyrrolate): routine co-use is controversial — can worsen hypertension and myocardial work (use to treat bradycardia judiciously)
• Atipamezole: specific reversal agent
• Sympathomimetics: unpredictable cardiovascular effects

Pregnancy and lactation

Avoid in pregnancy — alpha-2 agonists affect uterine tone and cause fetal cardiorespiratory depression. If used for caesarean, reverse promptly and resuscitate neonates.

Monitoring

• Heart rate/rhythm (ECG), mucous-membrane colour and blood pressure
• Respiratory rate and SpO2
• Depth of sedation; temperature (hypothermia)
• Recovery quality after atipamezole reversal

Toxicity and overdose

Overdose deepens the cardiovascular effects — severe bradycardia, AV block, hypotension, profound CNS and respiratory depression. Generally survivable with prompt reversal because the agent is specifically antagonisable.

Management: Antidote: atipamezole IM (dose typically ~5× the medetomidine microgram dose; follow product guidance) reverses sedation and cardiovascular effects. Support ventilation/oxygenation; treat clinically significant bradycardia per anaesthetic judgement; IV fluids for hypotension after the vasoconstrictive phase resolves.

Clinical pearls

• Reversibility is the headline benefit — keep atipamezole on hand for every alpha-2 sedation
• Dexmedetomidine has superseded medetomidine; if substituting, use ~half the microgram dose
• Combine with an opioid to slash the dose (and the cardiovascular hit) for the same sedation
• The pale mucous membranes and bradycardia are expected pharmacology (vasoconstriction), not necessarily an emergency — but reserve for cardiovascularly stable patients
• Reserve atropine for genuinely problematic bradycardia; routine co-administration can increase myocardial oxygen demand during the hypertensive phase

Mechanism of action

Selective alpha-2 adrenoceptor agonist. Stimulation of pre-synaptic alpha-2 receptors in the brainstem (locus coeruleus) reduces noradrenaline release → sedation and analgesia; spinal alpha-2 receptors contribute to analgesia. Peripheral post-synaptic alpha-2 receptors on vasculature cause an initial vasoconstrictive hypertension with reflex bradycardia, followed by reduced sympathetic tone.

Formulations and products

• Injection 1 mg/mL (1000 mcg/mL)
• Domitor (Zoetis (Orion)) — 1 mg/mL, Injection
• Medetomidine injection (Various (India)) — 1 mg/mL, Injection

Storage

Injection: 15–30 °C, protect from light; do not freeze.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other sedatives and anaesthetics

• Etomidate
• Guaifenesin (GGE)
• Isoflurane
• Ketamine HCl
• Midazolam
• Pentobarbital (Pentobarbitone)
• Phenobarbital
• Propofol

Frequently asked questions