Source: Marketing Authorisation Holder Revision Year: 2022
Ethicholine Injection is contraindicated in patients who are burnt, severely hyperkalaemic, or known to have atypical pseudocholinesterase. Ethicholine Injection is also contraindicated in patients with penetrating wounds of the eye, in patients with a personal or family history of malignant hyperpyrexia, in massively traumatised patients or those with extensive muscle degeneration, such as in recent paraplegia. Ethicholine Injection should not be administered to patients with known hypersensitivity to the drug. Ethicholine Injection is contraindicated in patients with known or suspected genetic susceptibility to malignant hyperthermia (see section Warnings and Pharmacogenomics).
The use of Ethicholine Injection is inadvisable in patients with low serum pseudocholinesterase concentrations such as may occur in patients with liver disease, malnutrition, severe anaemia, burns and in persons exposed to organophosphorus insecticides or weedkillers.
If eye drops containing long-acting cholinesterase inhibitor drugs such as ecothiopate iodide, dyflos, or demecarium bromide are used within a period of one month prior to an operation, the decreased serum cholinesterase levels may preclude the use of Ethicholine Injection.
The use of Ethicholine Injection is also inadvisable in patients with advanced myasthenia gravis, neurological defects, or myopathies.
In susceptible individuals, succinylcholine may trigger malignant hyperthermia, a skeletal muscle hypermetabolic state leading to high oxygen demand. Fatal outcomes of malignant hyperthermia have been reported.
The risk of developing malignant hyperthermia increases with the concomitant administration of succinylcholine and volatile anaesthetic agents. Ethicholine Injection can induce malignant hyperthermia in patients with known or suspected susceptibility based on genetic factors or family history, including those with certain inherited ryanodine receptor (RYR1) or dihydropyridine receptor (CACNA1S) variants (see section Contraindications and Pharmacogenomics).
Signs consistent with malignant hyperthermia may include hyperthermia, hypoxia, hypercapnia, muscle rigidity (e.g., jaw muscle spasm), tachycardia (e.g., particularly that unresponsive to deepening anaesthesia or analgesic medication administration), tachypnoea, cyanosis, arrhythmias, hypovolaemia, and haemodynamic instability. Skin mottling, coagulopathies, and renal failure may occur later in the course of the hypermetabolic process.
Successful treatment of malignant hyperthermia depends on early recognition of the clinical signs. If malignant hyperthermia is suspected, discontinue all triggering agents (i.e., volatile anaesthetic agents and succinylcholine), administer intravenous dantrolene sodium, and initiate supportive therapies. Consult prescribing information for intravenous dantrolene sodium for additional information on patient management. Supportive therapies include administration of supplemental oxygen and respiratory support based on clinical need, maintenance of haemodynamic stability and adequate urinary output, management of fluid and electrolyte balance, correction of acid base derangements, and institution of measures to control rising temperature.
Ethicholine Injection should be used with caution in patients with cardiac disease, those suffering from severe trauma or electrolyte imbalance, those receiving quinine or who have been recently digitilised as serious cardiac arrhythmias or cardiac arrest may be induced, those with pre-existing hyperkalaemia, paraplegic patients, and those who have suffered severe burns.
Ethicholine Injection should be used with caution, if at all, during ocular surgery and in patients with glaucoma.
The drug should be employed with caution in patients with fractures or muscle spasm because the initial muscle fasciculations may cause additional trauma.
When prolonged apnoea follows a single dose of suxamethonium chloride, neostigmine should not be given. Neostigmine and other anticholinesterase drugs are not antidotes to suxamethonium chloride but would normally have the effect of intensifying the depolarising effect. However, in some cases of prolonged apnoea, especially following large doses of Ethicholine by intravenous infusion, a state of ‘dual block’ may be responsible. In dual block, the muscle relaxation is due to nondepolarising blockade and is reversible with neostigmine. To investigate this possibility, the short-acting anticholinesterase drug, edrophonium, should be given; a transitory return of muscle power confirms the presence of dual block, which can then be reversed with neostigmine.
Sinus tachycardia and raised blood pressure have occurred following continuous infusion of suxamethonium chloride. Care should be taken with patients receiving systemic antibiotics such as streptomycin, neomycin, kanamycin, tobramycin, framycetin, amikacin, gentamicin, colistin and the polymyxins, as the action of suxamethonium chloride can be potentiated.
Ethicholine Injection may increase intragastric pressure, which may result in regurgitation and possible aspiration of stomach contents.
Suxamethonium chloride is reported to be unstable in alkaline solutions and to decompose in solutions with a pH greater than 4.5. Suxamethonium chloride is reported to be compatible with 5% dextrose injection and 0.9% sodium chloride injection.
It is reported that suxamethonium chloride should not be mixed with short-acting barbiturates in the same syringe or administered via the same line during IV infusion.
Since suxamethonium chloride is reported to be fairly quickly hydrolysed and destroyed by the alkalinity of thiopentone and moreover, since the initial contractions produced are painful if the thiopentone has not taken full effect, suxamethonium should be injected immediately after thiopentone and also from a different syringe.
Category A*.
Serum pseudocholinesterase concentrations are reduced in pregnancy and pregnant patients may show increased sensitivity to the drug.
Category A* = Drugs which have been taken by a large number of pregnant women and women of childbearing age without an increase in the frequency of malformations or other direct or indirect harmful effects on the foetus having been observed.
No problems have been documented in relation to the administration of suxamethonium during lactation.
Nevertheless, if it is to be given to women who are breast feeding, the benefits to the mother must be weighed against the potential adverse effect on the infant before administration.
Neonates and premature infants may be relatively resistant to Ethicholine Injection.
Intravenous bolus administration in infants or children may result in profound bradycardia, or rarely, asystole. As in adults, the incidence of bradycardia in children is higher following a second dose. The occurrence of bradyarrhythmias may be reduced by pretreatment with atropine. It has been suggested that continuous infusion is unsafe in children and neonates because of the risk of inducing malignant hyperpyrexia. In seriously burnt children, suxamethonium can precipitate gross cardiac arrhythmias and cardiac arrest. This can be prevented by the prior administration of 6 mg of tubocurarine, 5 minutes before giving suxamethonium.
Caution is required because of the possible cardiovascular effects of depolarising agents.
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