Succinylcholine is an intravenous (IV) skeletal muscle relaxant used as an adjunct to general anaesthesia, to help with tracheal intubation, and to relax skeletal muscles during surgery or mechanical ventilation. It’s referred to as “sux” by anesthesiologists. It is frequently used before to intubations since it totally calms the patient. It’s a depolarizer that works quickly and can be administered intravenously (IV) or intramuscularly (IM). It circulates in the bloodstream until it reaches nicotinic receptors on the surface of muscle cells, where it mimics the function of acetylcholine, a neurotransmitter released naturally by our neurons to move our muscles. When it’s administered, the patient fasciculates and all of his muscles get depolarized within seconds. In short, sux causes every muscle to twitch to the point where it is resistant to further stimulation.

Because its metabolites are all naturally occurring compounds, it is nearly hard to identify. A circulating enzyme called pseudocholinesterase breaks down most succinylcholine molecules in the blood into succinylmonocholine and choline. Because the procedure is so effective, only a tiny percentage of sux molecules administered really reach neuromuscular junctions. After that, succinylmonocholine is hydrolyzed to succinic acid, or succinate, which is a naturally occurring chemical.

Signs and Symptoms

The most frequent side effect of succinylcholine administration is hyperkalemia, which is caused by the drug’s stimulatory action on skeletal muscles.
cardiac arrest, life-threatening body temperature elevation, abnormal heart rhythms, fast or slow heart rate, high or low blood pressure, high blood potassium, prolonged slow breathing, increased eye pressure, muscle twitching, jaw rigidity, postoperative muscle pain, muscle tissue breakdown (rhabdomyolysis), excessive salivation, and rash are other severe side effect of succinylcholine poisoning.


Airway management and respiratory assistance sufficient for the patient to maintain adequate oxygenation until the medication is metabolised are the primary treatments and interventions for succinylcholine toxicity. Without mechanical assistance, the patient can maintain sufficient oxygenation and breathing.


Geyer BC, Larrimore KE, Kilbourne J, Kannan L, Mor TS. Reversal of succinylcholine induced apnea with an organophosphate scavenging recombinant butyrylcholinesterase. PLoS One. 2013;8(3):e59159. doi: 10.1371/journal.pone.0059159. Epub 2013 Mar 11. PMID: 23536865; PMCID: PMC3594170.

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