-threatening and fatal. due to the potential severity of these reactions, the necessary precautions, such as the immediate availability of appropriate emergency treatment, should be taken. precautions should also be taken in those individuals who have had previous anaphylactic reactions to other neuromuscular blocking agents since cross-reactivity between neuromuscular blocking agents, both depolarizing and non-depolarizing, has been reported in this class of drugs. risk of death due to medication errors administration of anectine results in paralysis, which may lead to respiratory arrest and death; this progression may be more likely to occur in a patient for whom it is not intended. confirm proper selection of intended product and avoid confusion with other injectable solutions that are present in critical care and other clinical settings. if another healthcare provider is administering the product, ensure that the intended dose is clearly labeled and communicated. hyperkalemia (see box warning .) succinylcholine should be administered with great caution to patients suffering from electrolyte abnormalities and those who may have massive digitalis toxicity, because in these circumstances succinylcholine may induce serious cardiac arrhythmias or cardiac arrest due to hyperkalemia. great caution should be observed if succinylcholine is administered to patients during the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury (see contraindications ). the risk of hyperkalemia in these patients increases over time and usually peaks at 7 to 10 days after the injury. the risk is dependent on the extent and location of the injury. the precise time of onset and the duration of the risk period are undetermined. patients with chronic abdominal infection, subarachnoid hemorrhage, or conditions causing degeneration of central and peripheral nervous systems should receive succinylcholine with great caution because of the potential for developing severe hyperkalemia. malignant hyperthermia 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 anesthetic agents. anectine 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 contraindications , clinical pharmacology; 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 anesthesia or analgesic medication administration), tachypnea, cyanosis, arrhythmias, hypovolemia, and hemodynamic 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 anesthetic 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 hemodynamic stability and adequate urinary output, management of fluid and electrolyte balance, correction of acid base derangements, and institution of measures to control rising temperature. other in both adults and pediatric patients, the incidence of bradycardia, which may progress to asystole, is higher following a second dose of succinylcholine. the incidence and severity of bradycardia is higher in pediatric patients than in adults. pretreatment with anticholinergic agents (e.g., atropine) may reduce the occurrence of bradyarrhythmias. succinylcholine causes an increase in intraocular pressure. it should not be used in instances in which an increase in intraocular pressure is undesirable (e.g., narrow angle glaucoma, penetrating eye injury) unless the potential benefit of its use outweighs the potential risk. succinylcholine is acidic (ph=3.5) and should not be mixed with alkaline solutions having a ph greater than 8.5 (e.g., barbiturate solutions).

oped phase ii block. tachyphylaxis was not associated with the transition to phase ii block, and 50% of the patients who developed phase ii block experienced prolonged recovery. when phase ii block is suspected in cases of prolonged neuromuscular blockade, positive diagnosis should be made by peripheral nerve stimulation prior to administration of any anticholinesterase drug. reversal of phase ii block is a medical decision which must be made upon the basis of the individual, clinical pharmacology, and the experience and judgment of the physician. the presence of phase ii block is indicated by fade of responses to successive stimuli (preferably “train-of-four”). the use of an anticholinesterase drug to reverse phase ii block should be accompanied by appropriate doses of an anticholinergic drug to prevent disturbances of cardiac rhythm. after adequate reversal of phase ii block with an anticholinesterase agent, the patient should be continually observed for at least 1 hour for signs of return of muscle relaxation. reversal should not be attempted unless: (1) a peripheral nerve stimulator is used to determine the presence of phase ii block (since anticholinesterase agents will potentiate succinylcholine-induced phase i block), and (2) spontaneous recovery of muscle twitch has been observed for at least 20 minutes and has reached a plateau with further recovery proceeding slowly; this delay is to ensure complete hydrolysis of succinylcholine by plasma cholinesterase prior to administration of the anticholinesterase agent. should the type of block be misdiagnosed, depolarization of the type initially induced by succinylcholine (i.e., phase i block) will be prolonged by an anticholinesterase agent. succinylcholine should be employed with caution in patients with fractures or muscle spasm because the initial muscle fasciculations may cause additional trauma. succinylcholine may cause a transient increase in intracranial pressure; however, adequate anesthetic induction prior to administration of succinylcholine will minimize this effect. succinylcholine may increase intragastric pressure, which could result in regurgitation and possible aspiration of stomach contents. neuromuscular blockade may be prolonged in patients with hypokalemia or hypocalcemia. since allergic cross-reactivity has been reported in this class, request information from your patients about previous anaphylactic reactions to other neuromuscular blocking agents. in addition, inform your patients that severe anaphylactic reactions to neuromuscular blocking agents, including anectine have been reported.

ut 1 minute; maximum blockade may persist for about 2 minutes, after which recovery takes place within 4 to 6 minutes. however, very large doses may result in more prolonged blockade. a 5- to 10-mg test dose may be used to determine the sensitivity of the patient and the individual recovery time (see precautions ). for long surgical procedures the dose of succinylcholine administered by infusion depends upon the duration of the surgical procedure and the need for muscle relaxation. the average rate for an adult ranges between 2.5 and 4.3 mg per minute. solutions containing from 1 to 2 mg per ml succinylcholine have commonly been used for continuous infusion. the more dilute solution (1 mg per ml) is probably preferable from the standpoint of ease of control of the rate of administration of the drug and, hence, of relaxation. this iv solution containing 1 mg per ml may be administered at a rate of 0.5 mg (0.5 ml) to 10 mg (10 ml) per minute to obtain the required amount of relaxation. the amount required per minute will depend upon the individual response as well as the degree of relaxation required. avoid overburdening the circulation with a large volume of fluid. it is recommended that neuromuscular function be carefully monitored with a peripheral nerve stimulator when using succinylcholine by infusion in order to avoid overdose, detect development of phase ii block, follow its rate of recovery, and assess the effects of reversing agents (see precautions ). intermittent iv injections of succinylcholine may also be used to provide muscle relaxation for long procedures. an iv injection of 0.3 to 1.1 mg/kg may be given initially, followed, at appropriate intervals, by further injections of 0.04 to 0.07 mg/kg to maintain the degree of relaxation required. pediatrics for emergency tracheal intubation or in instances where immediate securing of the airway is necessary, the iv dose of succinylcholine is 2 mg/kg for infants and small pediatric patients; for older pediatric patients and adolescents the dose is 1 mg/kg (see box warning and precautions: pediatric use ). rarely, iv bolus administration of succinylcholine in infants and pediatric patients may result in malignant ventricular arrhythmias and cardiac arrest secondary to acute rhabdomyolysis with hyperkalemia. in such situations, an underlying myopathy should be suspected. intravenous bolus administration of succinylcholine in infants or pediatric patients may result in profound bradycardia or, rarely, asystole. as in adults, the incidence of bradycardia in pediatric patients is higher following a second dose of succinylcholine. the occurrence of bradyarrhythmias may be reduced by pretreatment with atropine (see precautions: pediatric use ). intramuscular use if necessary, succinylcholine may be given intramuscularly to infants, older pediatric patients, or adults when a suitable vein is inaccessible. a dose of up to 3 to 4 mg/kg may be given, but not more than 150 mg total dose should be administered by this route. the onset of effect of succinylcholine given intramuscularly is usually observed in about 2 to 3 minutes. compatibility and admixtures succinylcholine is acidic (ph 3.5) and should not be mixed with alkaline solutions having a ph greater than 8.5 (e.g., barbiturate solutions). anectine injection is stable for 24 hours after dilution to a final concentration of 1 to 2 mg/ml in 5% dextrose injection, usp or 0.9% sodium chloride injection, usp. aseptic techniques should be used to prepare the diluted product. admixtures of anectine should be prepared for single patient use only. the unused portion of diluted anectine should be discarded.

and fatal. because these reactions were reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency (see warnings and precautions ).

sures are likely to be unsuccessful. careful monitoring of the electrocardiogram may alert the practitioner to peaked t-waves (an early sign). administration of iv calcium, bicarbonate, and glucose with insulin, with hyperventilation have resulted in successful resuscitation in some of the reported cases. extraordinary and prolonged resuscitative efforts have been effective in some cases. in addition, in the presence of signs of malignant hyperthermia, appropriate treatment should be initiated concurrently (see warnings ). since it is difficult to identify which patients are at risk, it is recommended that the use of succinylcholine in pediatric patients should be reserved for emergency intubation or instances where immediate securing of the airway is necessary, e.g., laryngospasm, difficult airway, full stomach, or for intramuscular use when a suitable vein is inaccessible. as in adults, the incidence of bradycardia in pediatric patients is higher following the second dose of succinylcholine. the incidence and severity of bradycardia is higher in pediatric patients than in adults. pretreatment with anticholinergic agents, e.g., atropine, may reduce the occurrence of bradyarrhythmias.

levator muscles of the face, muscles of the glottis, and finally, the intercostals and the diaphragm and all other skeletal muscles. succinylcholine has no direct action on the uterus or other smooth muscle structures. because it is highly ionized and has low fat solubility, it does not readily cross the placenta. tachyphylaxis occurs with repeated administration (see precautions ). depending on the dose and duration of succinylcholine administration, the characteristic depolarizing neuromuscular block (phase i block) may change to a block with characteristics superficially resembling a nondepolarizing block (phase ii block). this may be associated with prolonged respiratory muscle paralysis or weakness in patients who manifest the transition to phase ii block. when this diagnosis is confirmed by peripheral nerve stimulation, it may sometimes be reversed with anticholinesterase drugs such as neostigmine (see precautions ). anticholinesterase drugs may not always be effective. if given before succinylcholine is metabolized by cholinesterase, anticholinesterase drugs may prolong rather than shorten paralysis. succinylcholine has no direct effect on the myocardium. succinylcholine stimulates both autonomic ganglia and muscarinic receptors which may cause changes in cardiac rhythm, including cardiac arrest. changes in rhythm, including cardiac arrest, may also result from vagal stimulation, which may occur during surgical procedures, or from hyperkalemia, particularly in pediatric patients (see precautions: pediatric use ). these effects are enhanced by halogenated anesthetics. succinylcholine causes an increase in intraocular pressure immediately after its injection and during the fasciculation phase, and slight increases which may persist after onset of complete paralysis (see warnings ). succinylcholine may cause slight increases in intracranial pressure immediately after its injection and during the fasciculation phase (see precautions ). as with other neuromuscular blocking agents, the potential for releasing histamine is present following succinylcholine administration. signs and symptoms of histamine-mediated release such as flushing, hypotension, and bronchoconstriction are, however, uncommon in normal clinical usage. succinylcholine has no effect on consciousness, pain threshold, or cerebration. it should be used only with adequate anesthesia (see warnings ). pharmacogenomics ryr1 and cacna1s are polymorphic genes, and multiple pathogenic variants have been associated with malignant hyperthermia susceptibility (mhs) in patients receiving succinylcholine, including anectine. case reports as well as ex-vivo studies have identified multiple variants in ryr1 and cacna1s associated with mhs. variant pathogenicity should be assessed based on prior clinical experience, functional studies, prevalence information, or other evidence (see contraindications , warnings ).