Yohimbine: veterinary dose and monograph

At a glance

Drug class

Veterinary drug

Also known as

Yobine, Antagonil, Yohimbine hydrochloride

Species with doses

Dogs, Cats, Cattle, Horses, Sheep, Birds, Rabbits and Camelids

General dose range

0.1–0.125 mg/kg IV single dose (repeat if needed) — check the species tables for the indication

Routes

IV

Last reviewed

1 October 2026

Indications

• Reversal of xylazine sedation/anaesthesia (dogs, ruminants, horses, wildlife)
• Amitraz toxicosis — antidote (reverses CNS depression, bradycardia, hyperglycaemia)
• Reversal of other alpha-2 agonist overdose (alternative to atipamezole)

Yohimbine 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

• Xylazine reversal / amitraz toxicosis: Papich 5e: 0.11 mg/kg IV, or 0.25–0.5 mg/kg SC or IM. Plumb’s p.1179: xylazine reversal 0.1–0.11 mg/kg IV slowly (label); medetomidine 0.11 mg/kg IV; amitraz — 0.1 mg/kg IV repeated as needed (Manning; Hillier), or 0.11 mg/kg IV / 0.25 mg/kg IM with atipamezole 50 µg/kg IM (Torres 2007).

Cats

• Xylazine reversal: Papich 5e (dogs and cats): 0.11 mg/kg IV slowly, or 0.25–0.5 mg/kg SC or IM. (The previous 0.1–0.5 mg/kg IV mixed the IV and IM doses.)

Cattle

• Xylazine reversal: Papich 5e: cattle and sheep 0.125–0.2 mg/kg IV to reverse xylazine or medetomidine. Plumb’s p.1179: 0.125 mg/kg IV (Gross & Tranquilli); IM preferred except in emergencies (less excitement), 0.1 mg/kg IV in emergencies — wait 30–45 min after IM ketamine/Telazol before reversing (Anderson & Abrahamsen 2008). Obtain a FARAD withdrawal.

Horses

• Xylazine reversal: Plumb’s p.1179 (Gross & Tranquilli): 0.075 mg/kg IV. Papich 5e: 0.125 mg/kg IV for xylazine, 0.2 mg/kg IV for detomidine; the full dose may not be needed. Give slowly. ARCI Class 2.

Sheep

• Xylazine reversal: Papich 5e: cattle and sheep 0.125–0.2 mg/kg IV to reverse xylazine or medetomidine. Give slowly; atipamezole is an alternative.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Xylazine reversal: Papich 5e: cattle and sheep 0.125–0.2 mg/kg IV to reverse xylazine or medetomidine. Plumb’s p.1179: 0.125 mg/kg IV (Gross & Tranquilli); IM preferred except in emergencies (less excitement), 0.1 mg/kg IV in emergencies — wait 30–45 min after IM ketamine/Telazol before reversing (Anderson & Abrahamsen 2008). Obtain a FARAD withdrawal.

Birds

• Alpha-2 agonist reversal: Plumb’s p.1179 (Clyde & Paul-Murphy 2000): 0.1 mg/kg IV.

Rabbits

• Xylazine reversal: Plumb’s p.1179 (Huerkamp 1995): rabbits 0.2 mg/kg IV as needed; also partially antagonises ketamine and acepromazine. Mice/rats 0.2 mg/kg IP.

Camelids

• Xylazine reversal: Plumb’s p.1179 (Fowler 1989): llamas 0.25 mg/kg IV or IM.

Contraindications

Known hypersensitivity. Caution in seizure disorders, significant cardiac disease and hypertension (alpha-2 blockade raises sympathetic outflow → tachycardia, hypertension, excitement). Renal disease. Avoid rapid IV (transient excitement/cardiovascular effects).

Species-specific warnings

Cattle: Ruminants are exquisitely sensitive to xylazine; yohimbine is useful to hasten recovery from over-sedation.

Adverse effects

• Transient excitement/apprehension, muscle tremor
• Tachycardia, hypertension
• Hypersalivation
• Rapid reversal can unmask pain (if the alpha-2 was providing analgesia)

Drug interactions

• Alpha-2 agonists (xylazine, medetomidine, amitraz, clonidine): directly antagonised (the intended action) — reverses their effects
• Other sympathomimetics/stimulants: additive excitation, tachycardia, hypertension
• Tricyclic antidepressants/MAOIs: enhanced pressor effects

Pregnancy and lactation

Limited data; use when reversal is clinically needed. Rapid reversal in a pregnant animal should be balanced against the cardiovascular surge it produces.

Monitoring

• Recovery from sedation (arousal, posture, gait)
• Heart rate, rhythm and blood pressure (watch the post-reversal surge)
• For amitraz toxicosis: re-emergence of CNS depression/bradycardia (amitraz outlasts yohimbine — re-dose) and blood glucose
• Pain status if the alpha-2 was providing analgesia

Toxicity and overdose

Overdose causes sympathetic overstimulation — excitement/agitation, muscle tremor, tachycardia, hypertension and potentially seizures. Effects are generally short-lived because yohimbine is rapidly metabolised (which is also why repeat dosing is needed for the longer-acting amitraz).

Management: No specific antidote. Supportive — keep calm/quiet, IV fluids, and manage tachyarrhythmia/hypertension and seizures (benzodiazepines) as needed. Effects wane quickly with the drug's short half-life.

Clinical pearls

• The classic reverser for XYLAZINE — and the go-to antidote for AMITRAZ (tick dip/collar) toxicosis
• Amitraz lasts longer than a single yohimbine dose — expect signs to recur and be ready to re-dose plus give supportive care
• For medetomidine/dexmedetomidine, atipamezole is the more selective, usually preferred reversal agent
• Give slowly IV — rapid injection causes transient excitement, tachycardia and hypertension
• Reversal also reverses the alpha-2's analgesia — provide alternative pain relief if a painful procedure was performed

Mechanism of action

Competitive antagonist at alpha-2 adrenoceptors. By blocking central (pre-synaptic) alpha-2 receptors it removes the negative feedback on noradrenaline release, increasing central sympathetic outflow and arousal — thereby reversing the sedation, bradycardia and CNS/respiratory depression produced by alpha-2 agonists such as xylazine and amitraz. It also has some peripheral alpha-2-blocking and serotonergic activity.

Formulations and products

• Injection 2 mg/mL
• Yobine / Antagonil (Lloyd / various) — 2 mg/mL, Injection

Storage

Injection: 15–30 °C, protect from light.

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.

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Frequently asked questions