[Muscle relaxants].
BACKGROUND
Muscle relaxants were introduced into clinical anaesthesia for the first time in 1942. The purpose of this article is to provide an overview of the history of muscle relaxants, their mode of action and their role in current anaesthetic practice.


METHODS
The review is based on clinical experience, own research and a non-systematic literature search using PubMed.


RESULTS
A muscle relaxant is either suxamethonium (curacit) or one of many curare compounds. One of the curare drugs was brought to Europe from South America in the 1700 s and the active substance (called d-tubocurarine) was isolated in 1935. This type of drug paralyses striated muscles that are under voluntary control by interfering with the normal signalling system between nerve and muscle. Muscle relaxants provide optimal relaxation of skeletal muscles during surgical procedures, an effect that otherwise may require the use of high doses of anaesthetic drugs. However, muscle relaxants are not anaesthetic drugs, do not affect consciousness and have no pain relieving effect. A muscle relaxant that works optimally in all clinical settings has unfortunately not been developed so far.


CONCLUSIONS
Muscle relaxants are generally safe drugs when used appropriately, but especially suxamethonium may have serious side effects. A muscle relaxant is regularly used during induction of anaesthesia, but less during surgery, because modern anaesthetics possess some muscle relaxing effect.
Heier
Tom
T
Avdeling for anestesi, Oslo universitetssykehus, Aker 0514 Oslo, Norway. tom.heier@medisin.uio.no
D049673:History, 20th Century; D006801:Humans; D009045:Motor Endplate / Q000187:drug effects; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000266:history; D011229:Preanesthetic Medication; D011950:Receptors, Cholinergic / Q000187:drug effects; D013390:Succinylcholine / Q000008:administration & dosage / Q000009:adverse effects / Q000266:history; D014403:Tubocurarine / Q000008:administration & dosage / Q000009:adverse effects / Q000266:history
D003473:Neuromuscular Nondepolarizing Agents; D011950:Receptors, Cholinergic; D013390:Succinylcholine; D014403:Tubocurarine