Atracurium Besylate
Atracurium besylate
Also known as: Tracrium · Abbottracurium · Faulcurium · Ifacur · Laurak · Mycurium · Relatrac · Sitrac · Trablok · 33A74 · atracurium besilate · BW-33A
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 |
|---|---|---|---|---|---|
| Critically ill patients when low concentrations of, or no inhalant anesthesia can be used | 0.2 mg/kg IV initial dose; subsequent doses 0.1 mg/kg IV | IV | every 20-30 minutes | — | 🌎 NA |
| Neuromuscular blockade augmentation during corneal surgery | 0.15 mg/kg IV | IV | Single dose | — | 🌎 NA |
| Muscle relaxant to facilitate intubation in patients with severe blunt trauma | 0.25 mg/kg IV push | IV | Single dose | — | 🌎 NA |
| Induction of respiratory muscle paralysis during mechanical ventilation | Loading dose: 0.2-0.5 mg/kg IV, then a constant rate infusion 5 minutes later of 3-9 micrograms/kg/min | IV | CRI | — | 🌎 NA |
- Critically ill patients when low concentrations of, or no inhalant anesthesia can be used: Do not dose more frequently than every 20-30 minutes unless a peripheral nerve stimulator is applied, or voluntary movement is observed. Positive pressure ventilation required.
- Muscle relaxant to facilitate intubation in patients with severe blunt trauma: Given if patient requires intubation after IV acepromazine (0.01 mg/kg) + butorphanol (0.1 mg/kg) + ketamine (1 mg/kg).
- Induction of respiratory muscle paralysis during mechanical ventilation: Use D5W or 0.9% sodium chloride for diluent; do not mix with other drugs. Respiratory and cardiovascular monitoring should be provided.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Induction dose | 0.22 mg/kg IV | IV | Single dose | — | 🌎 NA |
| Intraoperative dose | 0.11 mg/kg IV | IV | As needed | — | 🌎 NA |
| Induction of respiratory muscle paralysis during mechanical ventilation | Loading dose: 0.2-0.5 mg/kg IV, then a constant rate infusion 5 minutes later of 0.37 micrograms/kg/min | IV | CRI | — | 🌎 NA |
| Critically ill patients when low concentrations of, or no inhalant anesthesia can be used | 0.2 mg/kg IV initial dose; subsequent doses 0.1 mg/kg IV | IV | every 20-30 minutes | — | 🌎 NA |
- Induction dose: Give 1/10th to 1/6th of this dose initially as a 'priming' dose, followed 4-6 minutes later with the remainder and a sedative/hypnotic agent.
- Induction of respiratory muscle paralysis during mechanical ventilation: Use D5W or 0.9% sodium chloride for diluent; do not mix with other drugs.
- Critically ill patients when low concentrations of, or no inhalant anesthesia can be used: Do not dose more frequently than every 20-30 minutes unless a peripheral nerve stimulator is applied. Positive pressure ventilation required.
Small Mammals
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Paralysis for periophthalmic surgery (Rabbits) | 0.1 mg/kg | IV | Single dose | — | 🌎 NA |
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Intraoperative dose | 0.055 mg/kg IV | IV | As needed | — | 🌎 NA |
- Intraoperative dose: Note: ARCI UCGFS Class 2 Drug. Atracurium is more potent in horses than in other species.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Atracurium is a highly utilized nondepolarizing neuromuscular blocking agent used primarily as an adjunct to general anesthesia. It provides profound skeletal muscle relaxation to facilitate surgical procedures, endotracheal intubation, and mechanical ventilation.
Key Clinical Pearls:
- Organ-Independent Elimination: Atracurium undergoes Hofmann elimination and ester hydrolysis, making it exceptionally valuable for patients with significant renal or hepatic disease.
- No Analgesia or Sedation: It paralyzes the patient but provides absolutely zero pain relief or unconsciousness. It must never be used as a sole agent.
- Cardiovascular Stability: At standard doses, it exhibits minimal cardiovascular effects compared to older neuromuscular blockers, though it can occasionally trigger histamine release.
- Species Sensitivity: It is notably more potent in horses than in other species.
Mechanism of action
Atracurium acts by competitively binding to nicotinic cholinergic receptors at the motor end-plate of the neuromuscular junction.
By occupying these receptors, it prevents acetylcholine (ACh) from binding → inhibits depolarization of the muscle cell membrane → results in flaccid paralysis of skeletal muscles.
Because it is a competitive antagonist, its effects can be reversed by increasing the concentration of ACh at the neuromuscular junction (e.g., by administering acetylcholinesterase inhibitors like neostigmine or edrophonium).
Safety & warnings
Contraindications
- Hypersensitivity to atracurium
- Relative contraindication: Myasthenia gravis
- Lack of ventilatory support (must have mechanical ventilation available)
Adverse effects
- Allergic reactions
- Inadequate or prolonged neuromuscular block
- Hypotension
- Vasodilation
- Bradycardia
- Tachycardia
- Dyspnea
- Bronchospasm
- Laryngospasm
- Rash
- Urticaria
- Injection site reaction
Precautions
CRITICAL WARNING: Atracurium has NO analgesic or sedative/anesthetic actions. Patients must be appropriately sedated/anesthetized and provided with analgesia.
- Ventilation: Positive pressure ventilation (preferably mechanical) is absolutely required when using this drug.
- Histamine Release: May rarely cause significant histamine release; use with caution in patients where this would be hazardous (e.g., severe cardiovascular disease, asthma).
- Myasthenia Gravis: Use with extreme caution, or not at all, in patients suffering from myasthenia gravis.
- Vagal Tone: Has minimal cardiac effects and will not counteract bradycardia or vagal stimulation induced by other anesthetic agents.
Drug interactions
May enhance the neuromuscular blocking activity of atracurium
May enhance and prolong the neuromuscular blocking activity
May enhance neuromuscular blocking activity
May enhance neuromuscular blocking activity
May enhance neuromuscular blocking activity
May enhance neuromuscular blocking activity
May enhance neuromuscular blocking activity
Reported to decrease both the effects and duration of neuromuscular blockade
May cause a synergistic or antagonistic effect
May speed the onset of action and enhance the neuromuscular blocking actions of atracurium. Do not give atracurium until succinylcholine effects have diminished.
Monitoring
- Level of neuromuscular blockade (recommend use of a peripheral nerve stimulator to evaluate 'train of 4' twitches)
- Spontaneous ventilation and voluntary muscle movement (if nerve stimulator is unavailable)
- Cardiac rate and blood pressure
- Core body temperature and acid-base status (can affect drug metabolism)
Pharmacokinetics
Absorption
After IV injection, maximal neuromuscular blockade generally occurs within 3-5 minutes. Duration of blockade generally persists for 20-35 minutes.
Metabolism
Metabolized by ester hydrolysis and Hofmann elimination that occur independently of renal or hepatic function. Physiologic pH and temperature can affect elimination (increased body temp enhances elimination; decreased pH enhances ester hydrolysis but reduces Hofmann elimination).
Elimination
Eliminated via Hofmann degradation and ester hydrolysis. Systemic alkalosis may diminish the degree and duration of blockade; acidosis potentiates it.
Overdose
Overdosage increases the risks of hypotension, histamine release, and prolonged duration of muscle blockade. Overdose possibilities can be minimized by monitoring muscle twitch responses to peripheral nerve stimulation.
Treatment:
- Treat conservatively with mechanical ventilation, oxygen, and IV fluids.
- Reversal of blockade: May be accomplished by administering an anticholinesterase agent such as edrophonium (0.5 mg/kg IV) or neostigmine (0.02-0.04 mg/kg IV) combined with an anticholinergic (atropine or glycopyrrolate) to prevent severe bradycardia.
- Reversal is usually complete within 8-10 minutes. Because the duration of action of atracurium may be longer than the reversal agent, careful observation is required, and readministration of the reversal agent may be necessary.
Available products
Formulations
- Injection
Human-labeled
- Atracurium Besylate Injection: 10 mg/mL in 5 mL single-use & 10 mL multiuse vials (Tracrium, generic)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store in the refrigerator (2-8°C) and protect against freezing. At room temperature, approximately 5% potency loss occurs each month; when refrigerated, a 6% potency loss occurs over a year's time. Incompatible when mixed with alkaline drugs (e.g., barbiturates, sodium bicarbonate), propofol, diazepam, thiopental, aminophylline, cefazolin, heparin, ranitidine, and sodium nitroprusside.
Client information
This medication is a highly specialized muscle relaxant used exclusively by veterinary professionals during general anesthesia or critical care mechanical ventilation.
- It ensures your pet remains perfectly still during delicate surgeries (like eye surgery) or helps them breathe in sync with a ventilator if they are critically ill.
- Because it only relaxes muscles and does not provide pain relief or sleep, it is always given alongside strong pain medications and sedatives or anesthetics to ensure your pet is completely unconscious and comfortable.
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.