Marketed as Suxamethonium, succinylcholine is a depolarizing muscle relaxant, first used in 1951 as a muscle relaxant. It is still used today for rapid sequence induction.

Succinylcholine is essentially two acetylcholine molecules joined together and as it resembles the ACh molecule, it binds to the acetylcholine receptor at the neuromuscular junction causing an depolarization and an endplate potential. However, as it is only weakly affected by acetylcholinesterase, and is metabolized by pseudocholinesterase, it stays in the synaptic cleft, bound to the ACh receptor and creates tetany which fatigues the muscles, causing them to relax.

Onset of action is rapid (under 60s) while duration of action is short (under 10 minutes). In individuals with pseudocholinesterase deficiency (about 1 in 3000 or less), the duration of action will be much longer and succinylcholine should be avoided in these people if possible.

Also be careful of using this drug in anyone with myasthenia gravis or any other disease affecting neuromuscular junctions.

The chemical structure of this drug is: