SUCCINYLCHOLINE CHLORIDE — succinylcholine chloride injection, solution
Somerset Therapeutics, LLC
- Acute rhabdomyolysis with hyperkalemia followed by ventricular dysrhythmias, cardiac arrest, and death has occurred after the administration of succinylcholine to apparently healthy pediatric patients who were subsequently found to have undiagnosed skeletal muscle myopathy, most frequently Duchenne muscular dystrophy [see Warnings and Precautions (5.1)].
- When a healthy appearing pediatric patient develops cardiac arrest within minutes after administration of succinylcholine chloride injection, not felt to be due to inadequate ventilation, oxygenation or anesthetic overdose, immediate treatment for hyperkalemia should be instituted. In the presence of signs of malignant hyperthermia, appropriate treatment should be instituted concurrently [see Warnings and Precautions (5.1)].
- Reserve the use of succinylcholine chloride injection in pediatric patients 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 [see Warnings and Precautions (5.1)].
- as an adjunct to general anesthesia
- to facilitate tracheal intubation
- to provide skeletal muscle relaxation during surgery or mechanical ventilation.
- Succinylcholine chloride injection is for intravenous or intramuscular use only.
- Succinylcholine chloride injection must be titrated to effect by or under supervision of experienced clinicians who are familiar with its actions and with appropriate neuromuscular monitoring techniques.
- Succinylcholine chloride injection should be administered only by those skilled in the management of artificial respiration and only when facilities are instantly available for tracheal intubation and for providing adequate ventilation of the patient, including the administration of oxygen under positive pressure and the elimination of CO2 . The clinician must be prepared to assist or control respiration.
- The dosage of succinylcholine chloride injection should be individualized and should always be determined by the clinician after careful assessment of the patient.
- To avoid distress to the patient, do not administer succinylcholine chloride injection before unconsciousness has been induced [see Warnings and Precautions (5.14)].
- The occurrence of bradyarrhythmias with administration of succinylcholine chloride injection may be reduced by pretreatment with anticholinergics (e.g., atropine) [see Warnings and Precautions (5.6)].
- Monitor neuromuscular function with a peripheral nerve stimulator when using succinylcholine chloride injection by infusion [see Dosage and Administration (2.2), Warnings and Precautions (5.8)].
- Visually inspect succinylcholine chloride injection for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not administer solutions that are not clear and colorless.
- Succinylcholine chloride injection supplied in single-dose vials must be diluted before use. Succinylcholine chloride injection supplied in multiple- dose vials does not require dilution before use [see Dosage and Administration (2.5)].
Accidental administration of neuromuscular blocking agents may be fatal. Store succinylcholine chloride injection with the cap and ferrule intact and in a manner that minimizes the possibility of selecting the wrong product [see Warnings and Precautions (5.3)].
The average dose required to produce neuromuscular blockade and to facilitate tracheal intubation is 0.6 mg/kg succinylcholine chloride injection given intravenously. The optimum intravenous dose of succinylcholine chloride injection will vary among patients and may be from 0.3 mg/kg to 1.1 mg/kg for adults. Following intravenous administration of doses in this range, neuromuscular blockade develops in about 1 minute; maximum blockade may persist for about 2 minutes, after which recovery takes place within 4 to 6 minutes. A 5 to 10 mg intravenous test dose of succinylcholine chloride injection may be used to determine the sensitivity of the patient and the individual recovery time [see Warnings and Precautions (5.9)].
For Long Surgical Procedures
Continuous Intravenous Infusion
The dosage of succinylcholine chloride injection administered by continuous intravenous infusion depends upon the duration of the surgical procedure and the need for muscle relaxation.
Diluted succinylcholine chloride solutions containing from 1 mg/mL to 2 mg/mL succinylcholine have commonly been used for continuous intravenous infusion [see Dosage and Administration (2.5)]. The more dilute solution (1 mg/mL) is probably preferable from the standpoint of ease of control of the rate of administration of succinylcholine chloride injection and, hence, of relaxation. This diluted succinylcholine chloride solution containing 1 mg/mL succinylcholine may be administered intravenously at a rate of 0.5 mg (0.5 mL) per minute 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. The average rate of continuous intravenous infusion for an adult ranges between 2.5 mg per minute and 4.3 mg per minute.
Monitor neuromuscular function with a peripheral nerve stimulator when using succinylcholine chloride injection 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 Warnings and Precautions (5.8)].
Intermittent Intravenous Injection
Intermittent intravenous injections of succinylcholine chloride injection may also be used to provide muscle relaxation for long procedures. An intravenous injection of 0.3 mg/kg to 1.1 mg/kg may be given initially, followed, at appropriate intervals, by further intravenous injections of 0.04 mg/kg to 0.07 mg/kg to maintain the degree of relaxation required.
For emergency tracheal intubation or in instances where immediate securing of the airway is necessary, the intravenous dose of succinylcholine chloride injection is 2 mg/kg for infants and other small pediatric patients; for older pediatric patients and adolescents the intravenous dose is 1 mg/kg [see Warnings and Precautions (5.1), Use in Specific Populations (8.4)]. The effective dose of succinylcholine chloride injection in pediatric patients may be higher than that predicted by body weight dosing alone. For example, the usual adult intravenous dose of 0.6 mg/kg is comparable to a dose of 2 mg/kg to 3 mg/kg in neonates and infants up to 6 months of age and 1 mg/kg to 2 mg/kg in infants up to 2 years of age [see Clinical Pharmacology (12.3)].
If a suitable vein is inaccessible, succinylcholine chloride injection may be administered intramuscularly at a dose of up to 3 mg/kg to 4 mg/kg to infants, older pediatric patients, or adults. The total dose administered by the intramuscular route should not exceed 150 mg. The onset of effect of succinylcholine given intramuscularly is usually observed in about 2 to 3 minutes.
Succinylcholine chloride injection may be diluted to 1 mg/mL or 2 mg/mL in a solution such as:
- 5% Dextrose Injection, USP, or
- 0.9% Sodium Chloride Injection, USP
Prepare the diluted succinylcholine chloride solution for single patient use only. Store the diluted succinylcholine chloride solution in a refrigerator [2 °C to 8 °C (36 °F to 46 °F)] and use within 24 hours after preparation. Visually inspect the diluted succinylcholine chloride solution for particulate matter and discoloration prior to administration. Do not administer solutions that are not clear and colorless. Discard any unused portion of the diluted succinylcholine chloride solution.
Succinylcholine chloride injection is acidic (pH is between 3.0 and 4.5) and may not be compatible with alkaline solutions having a pH greater than 8.5 (e.g., barbiturate solutions). Therefore, do not mix succinylcholine chloride injection with alkaline solutions.
- 200 mg/10 mL (20 mg/mL) in multiple-dose fliptop vials contains: 20 mg of succinylcholine anhydrous (equivalent to 22.65 mg of Succinylcholine Chloride, USP).
- in patients with skeletal muscle myopathies [see Warnings and Precautions (5.1)]
- in patients with known hypersensitivity to succinylcholine. Severe anaphylactic reactions to succinylcholine have been reported [see Warnings and Precautions (5.2)]
- after the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury, which may result in severe hyperkalemia and cardiac arrest [see Warnings and Precautions (5.4)]
- in patients with personal or familial history of malignant hyperthermia [see Warnings and Precautions (5.5)]
5.1 Ventricular Dysrhythmias, Cardiac Arrest, and Death From Hyperkalemic Rhabdomyolysis in Pediatric Patients
There have been reports of ventricular dysrhythmias, cardiac arrest, and death secondary to acute rhabdomyolysis with hyperkalemia in apparently healthy pediatric patients who received succinylcholine. Many of these pediatric patients were subsequently found to have a skeletal muscle myopathy such as Duchenne muscular dystrophy whose clinical signs were not obvious.
The syndrome often presented as sudden cardiac arrest within minutes after the administration of succinylcholine. These pediatric patients were usually, but not exclusively, males, and most frequently 8 years of age or younger. There have also been reports in adolescents. There may be no signs or symptoms to alert the practitioner to which patients are at risk. A careful history and physical may identify developmental delays suggestive of a myopathy. A preoperative creatine kinase could identify some but not all patients at risk.
When a healthy-appearing pediatric patient develops cardiac arrest within minutes after administration of succinylcholine chloride injection, not felt to be due to inadequate ventilation, oxygenation or anesthetic overdose, immediate treatment for hyperkalemia should be instituted. Due to the abrupt onset of this syndrome, routine resuscitative measures are likely to be unsuccessful. Careful monitoring of the electrocardiogram may alert the practitioner to peaked T-waves (an early sign). Administration of intravenous 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 and Precautions (5.5)].
Because it is difficult to identify which patients are at risk, reserve the use of succinylcholine chloride injection in pediatric patients 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.
Severe anaphylactic reactions to neuromuscular blocking agents, including succinylcholine, have been reported. These reactions have, in some cases, been life-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. Allergic cross-reactivity between neuromuscular blocking agents, both depolarizing and non-depolarizing, has been reported in this class of drugs. Therefore, assess patients for previous anaphylactic reactions to other neuromuscular blocking agents before administering succinylcholine chloride injection.
Administration of succinylcholine chloride injection 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.
Succinylcholine chloride injection is contraindicated after the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury [see Contraindications (4)]. 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 are at an increased risk of developing severe hyperkalemia after succinylcholine chloride injection administration. Consider avoiding use of succinylcholine chloride injection in these patients or verify the patient’s baseline potassium levels are within the normal range prior to succinylcholine chloride injection administration.
Succinylcholine administration has been associated with acute onset of malignant hyperthermia, a potentially fatal hypermetabolic state of skeletal muscle. The risk of developing malignant hyperthermia following succinylcholine administration increases with the concomitant administration of volatile anesthetics. Malignant hyperthermia frequently presents as intractable spasm of the jaw muscles (masseter spasm) which may progress to generalized rigidity, increased oxygen demand, tachycardia, tachypnea and profound hyperpyrexia. Successful outcome depends on recognition of early signs, such as jaw muscle spasm, acidosis, or generalized rigidity to initial administration of succinylcholine for tracheal intubation, or failure of tachycardia to respond to deepening anesthesia. Skin mottling, rising temperature and coagulopathies may occur later in the course of the hypermetabolic process. Recognition of the syndrome is a signal for discontinuance of anesthesia, attention to increased oxygen consumption, correction of acidosis, support of circulation, assurance of adequate urinary output and institution of measures to control rising temperature. Intravenous dantrolene sodium is recommended as an adjunct to supportive measures in the management of malignant hyperthermia. Consult the dantrolene prescribing information for additional information about the management of malignant hyperthermic crisis. Continuous monitoring of temperature and expired CO2 is recommended as an aid to early recognition of malignant hyperthermia.
Intravenous bolus administration of succinylcholine chloride injection in pediatric patients (including infants) may result in profound bradycardia or, rarely, asystole. In both adult 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 adults. Whereas bradycardia is common in pediatric patients after an initial dose of 1.5 mg/kg, bradycardia is seen in adults only after repeated exposure. Pretreatment with anticholinergic agents (e.g., atropine) may reduce the occurrence of bradyarrhythmias.
Succinylcholine causes an increase in intraocular pressure. Avoid succinylcholine chloride injection 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.
When succinylcholine chloride injection is given over a prolonged period of time, the characteristic depolarization block of the myoneural junction (Phase I block) may change to a block with characteristics superficially resembling a non-depolarizing block (Phase II block). Prolonged respiratory muscle paralysis or weakness may be observed in patients manifesting this transition to Phase II block. Tachyphylaxis occurs with repeated administration [see Clinical Pharmacology (12.2)].
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 patient, clinical pharmacology, and the experience and judgment of the clinician. 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 such as neostigmine 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.
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