Atracurium
Atracurium besylate
Also known as: Tracrium · Nimbex · Atracurium besilate · Atracurium besylate · cis-Atracurium
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Neuromuscular blockade during anaesthesia | 0.2-0.5 mg/kg initially, followed by increments of 0.2 mg/kg | IV | as needed | Intermediate duration (15-35 min) | 🌍 EU |
- Neuromuscular blockade during anaesthesia: Monitor with nerve stimulator
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Neuromuscular blockade during anaesthesia | 0.2-0.5 mg/kg initially, followed by increments of 0.2 mg/kg | IV | as needed | Intermediate duration (15-35 min) | 🌍 EU |
- Neuromuscular blockade during anaesthesia: Monitor with nerve stimulator
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Atracurium is an intermediate-acting, non-depolarizing neuromuscular blocking agent used in veterinary anesthesia. It provides neuromuscular blockade to improve surgical access through muscle relaxation, facilitates positive pressure ventilation, and is particularly useful for intraocular surgery (e.g., to centralize the globe).
It has an intermediate duration of action (15-35 minutes) and is non-cumulative due to its unique non-enzymatic degradation pathway (Hofmann elimination). Because its clearance is independent of hepatic and renal function, it is highly suitable for administration to animals with renal or hepatic disease.
Clinical Pearl: Atracurium does not provide any analgesic or sedative effects. It must strictly be used in fully anesthetized patients.
Mechanism of action
Atracurium acts as a competitive antagonist at the neuromuscular junction.
It inhibits the actions of acetylcholine → binds competitively to the nicotinic acetylcholine receptors on the post-junctional membrane of skeletal muscle → prevents acetylcholine from binding → prevents muscle cell depolarization → results in flaccid muscle paralysis.
Safety & warnings
Contraindications
- Conscious or inadequately anesthetized animals
- Lack of positive pressure ventilation facilities
- Lack of trained personnel to monitor neuromuscular blockade
- Conscious animals (must NEVER be administered unless the animal is adequately anesthetized)
Adverse effects
- Histamine release (especially with rapid IV injection)
- Bronchospasm
- Hypotension
- Tachycardia
- Histamine release (especially with rapid IV administration)
Precautions
CRITICAL WARNING: Do not administer unless the animal is adequately anaesthetized and facilities to provide positive pressure ventilation are available.
- Histamine Release: Can precipitate the release of histamine after rapid IV administration, resulting in bronchospasm and hypotension. Diluting the drug in normal saline and giving it slowly IV minimizes these effects.
- Physiological Factors: Hypothermia, acidosis, and hypokalaemia will prolong the duration of action of the neuromuscular blockade.
- Myasthenia Gravis: Use the low end of the dose range in patients with myasthenia gravis.
- Monitoring: Monitoring (using a peripheral nerve stimulator) and pharmacological reversal of the neuromuscular blockade is strongly recommended to ensure complete recovery before the end of anaesthesia.
Drug interactions
Prolonged neuromuscular blockade
Prolonged neuromuscular blockade
Prolonged neuromuscular blockade
Prolonged neuromuscular blockade
Monitoring
- Respiratory rate and effort (mechanical ventilation parameters)
- End-tidal CO2 (capnography)
- Oxygen saturation (pulse oximetry)
- Heart rate and rhythm (ECG)
- Neuromuscular function (using a peripheral nerve stimulator/Train-of-Four monitor)
- Respiratory rate, effort, and end-tidal CO2
- Heart rate and blood pressure
- Core body temperature (hypothermia prolongs effect)
- Acid-base status and potassium levels
Pharmacokinetics
Half-life
Absorption
Administered intravenously; 100% bioavailability.
Distribution
Limited volume of distribution, primarily restricted to the extracellular fluid space.
Metabolism
Undergoes non-enzymatic Hofmann elimination (dependent on normal body pH and temperature) and hydrolysis by non-specific plasma esterases. Metabolism is independent of hepatic and renal function.
Elimination
Metabolites (e.g., laudanosine) are excreted via urine and bile.
Overdose
Overdosage results in prolonged neuromuscular blockade and respiratory paralysis.
- Management: Requires continuous mechanical positive pressure ventilation until spontaneous recovery occurs.
- Reversal: Pharmacological reversal agents (e.g., neostigmine or edrophonium) combined with an anticholinergic (e.g., atropine or glycopyrrolate to prevent severe bradycardia) should be administered once signs of spontaneous recovery begin (confirmed via nerve stimulator).
Available products
Formulations
- Injectable: 10 mg/ml solution
Human-labeled
- Tracrium 10 mg/ml solution for injection
Regulatory status
POM (Prescription Only Medicine)
POM (Prescription Only Medicine)
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store in a refrigerator (2°C - 8°C). Do not freeze. Protect from light. Once drawn up or diluted, it should be used promptly.
Client information
This medication is a specialized muscle relaxant used strictly in a hospital setting during general anesthesia. It is administered by a veterinarian while your pet is fully asleep and connected to a breathing machine. It ensures the muscles are completely relaxed to allow the surgeon to perform delicate procedures safely.
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.