Suxamethonium
Suxamethonium chloride
Also known as: Anectine · Quelicin · Succinylcholine · Suxamethonium chloride
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Dosing by species
Dosing data for this drug is not yet available in the VetSheet formulary. Every other section below is complete. Consult the current product label before prescribing.
Overview
Suxamethonium (also known as succinylcholine) is an ultra-short-acting depolarizing neuromuscular blocking agent. It is primarily used in veterinary medicine to facilitate rapid endotracheal intubation and provide skeletal muscle relaxation during surgery.
Clinical Pearl: Because it is a depolarizing agent, its use is often preceded by transient muscle fasciculations. It provides no analgesia or sedation; patients must be fully anesthetized and mechanically ventilated.
Mechanism of action
Competitively binds to the nicotinic acetylcholine receptor at the neuromuscular junction. The persistent depolarization prevents the transmission of further action potentials → resulting in flaccid muscle relaxation.
Safety & warnings
Contraindications
- Patients with pre-existing hyperkalemia
- Glaucoma or penetrating eye injuries
- Severe liver disease
- Patients with known atypical plasma pseudocholinesterase
- Conscious patients (must be fully anesthetized)
Adverse effects
- Muscle fasciculations
- Hyperkalemia
- Bradycardia or arrhythmias
- Malignant hyperthermia
- Increased intraocular pressure
- Increased intragastric pressure
- Prolonged apnea
Precautions
Requires mechanical ventilation. Do not use without the immediate ability to intubate and ventilate the patient. No analgesic properties: Does not provide analgesia or sedation; ensure adequate depth of anesthesia before administration. Hyperkalemia risk: Use with extreme caution in patients with extensive tissue trauma, burns, or upper motor neuron lesions due to the risk of severe hyperkalemia.
Drug interactions
Inhibit pseudocholinesterase, leading to significantly prolonged neuromuscular blockade
Inhibit pseudocholinesterase, leading to significantly prolonged neuromuscular blockade
May enhance or prolong neuromuscular blockade
Enhanced neuromuscular blockade and increased risk of malignant hyperthermia
Monitoring
- Heart rate and rhythm (ECG)
- Blood pressure
- Oxygen saturation (SpO2)
- End-tidal CO2 (Capnography)
- Body temperature (monitor for malignant hyperthermia)
- Peripheral nerve stimulation (Train-of-Four) to assess blockade depth and recovery
Pharmacokinetics
Half-life
Absorption
Rapid onset following IV or IM administration.
Distribution
Highly ionized with low lipid solubility; does not cross the blood-brain barrier or placenta significantly.
Metabolism
Rapidly hydrolyzed by plasma pseudocholinesterase into succinylmonocholine and then to succinic acid and choline.
Elimination
Primarily eliminated via enzymatic degradation in the plasma; a small amount is excreted unchanged in the urine.
Overdose
Overdose results in prolonged neuromuscular blockade and extended apnea.
Treatment is strictly supportive with continuous mechanical ventilation and maintenance of anesthesia until the drug is fully metabolized and spontaneous respiration returns. There is no specific pharmacological reversal agent for depolarizing neuromuscular blockers.
Available products
Formulations
- Injectable: 50 mg/ml solution
Human-labeled
- Suxamethonium chloride 50 mg/ml solution for injection
Regulatory status
Human-approved products used off-label in veterinary medicine.
Typically used under the cascade using human-registered products.
Used under the prescribing cascade.
No regulatory data for: 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store in a refrigerator (2°C - 8°C). Do not freeze. Protect from light.
Client information
This medication is a specialized muscle relaxant used strictly in a hospital setting under general anesthesia. It is used to relax muscles during surgery or to help place a breathing tube. It is never prescribed for home use.
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.