Suxaméthonium

Properties

Pharmacological effects

The suxaméthonium is a Dimère of Acétylcholine. It acts by setting in a noncompetitive way on the nicotinic receiving within the driving Plaque, involving a prolonged depolarization of the muscular membrane and thus returning it inexcitable; the characteristic of suxaméthonium is to resist the action of the acétylcholinestérase, which in a physiological way degrades acetylcholine and cancels its effect in a few milliseconds. Contrary, the suxaméthonium remains fixed on the receiver, being inactivated by the pseudocholinestérases plasma only after several minutes.

Clinical effects

The suxaméthonium induces a total paralysis of the voluntary musculature within 30 to 60 seconds and for one short duration, not exceeding 10 minutes. Because of its depolarizing activity, its first clinical sign of action is the appearance of Fasciculation S muscular.

Use in medicine

Indications

Because of its exceptionally short time of action and its weak duration of action, the suxaméthonium is the curare of choice for the Intubation in fast sequence at a patient deadened beforehand, in the absence of counter-indication and in certain well codified situations (in particular patient with the stomach full or the risk with inhalation of gastric liquid, in particular during Césarienne S in urgency). The suxaméthonium is indicated for the curarization of the patients treated by Sismothérapie. It is also possible to use it for intuber in programmed surgical operations of short duration. N the other hand, it is necessary to prefer to him or associate to him a curare not-depolarizer for the interventions requiring a curarization of more than ten minutes.

Counter-indications

The suxaméthonium can be used only in the presence of material of anesthesia allowing intubation and the respiratory assistance. It is formally contra-indicated in the event of Hyperkaliémie (risk of acute aggravation with cardiac consequences), of Allergie to this product or to a curare not-depolarizer (risk of Choc anaphylactic), of personal or family antecedent of disease of the neuro-muscular apparatus (malignant Hyperthermie, Myopathie, Paraplégie,…), of deficit in pseudocholinestérases (risk of prolonged curarization).

Undesirable effects

The undesirable effects of suxaméthonium are the main obstacle with its routine use. Most frequent are also the least serious: they are represented by the Bradycardie (prevented by the Atropine), the arterial Hypotension, the spasm of the Masséter S, the transitory increase in the intraocular, intra-abdominal pressure and intracranial, and by Courbature S with the alarm clock. The others are much rarer, and some can be fatal: Rhabdomyolyse acute with Hyperkaliémie massive in the event of muscular brittleness, allergic reaction being able to go until the Shock anaphylactic, release of a malignant crisis of Hyperthermia at the subjects predisposed in the event of association with anesthetic halogenous, curarization prolonged at the plasmatic subjects presenting a deficit in pseudocholinestérases.

Advanced

Since years research is focused on the development of a curare not-depolarizer which would have the advantages of the suxaméthonium (fast time of action, duration of short action, very good conditions of intubation) without having the undesirable effects of them. To date no molecule joins together all these criteria. In the event of counter-indication with suxaméthonium, the Rocuronium (which acts as 90 seconds) seems currently the best choice for intuber in the event of full stomach, at the price of a curarization of more than 40 minutes.

References

Conference of consensus of the SFAR , 2001

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