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Action/Kinetics:
A nondepolarizing neuromuscular blocking agent that acts by competing with acetylcholine for receptors at the motor end-plate. Causes histamine release in a small number of clients. Use must be accompanied by adequate anesthesia or sedation, as the drug has no effect on consciousness, pain threshold, or cerebration. Depending on the dose, it has a rapid to intermediate onset and an intermediate duration of action.
t
1/2, rapid distribution phase: 1-2 min;
t
1/2, slower distribution phase: 14-18 min. Metabolized by the liver.
Uses:
As an adjunct to general anesthesia to facilitate rapid sequence and routine tracheal intubation; also, to cause relaxation of skeletal muscle during surgery or mechanical ventilation.
Special Concerns:
Use with caution in clients with pulmonary hypertension, valvular heart disease, or significant hepatic disease. Burn clients may develop resistance to nondepolarizing neuromuscular blocking agents. Elderly clients may exhibit a slightly prolonged medical clinical duration of action. Use in children less than 3 months of age has not been studied.
Side Effects:
CV: Arrhythmias, abnormal ECG, transient hypotension and hypertension, tachycardia.
GI: N&V.;
Respiratory: Symptoms of asthma, including
bronchospasm wheezing, rhonchi; hiccup.
Dermatologic: Rash, edema at injection site, pruritus.
Overdose Management:
Symptoms: Neuromuscular blockade longer than needed for anesthesia and surgery.
Treatment: Careful monitoring of client. Artificial respiration may be required.
How Supplied:
Injection: 10 mg/ml
Dosage
?IV Only
Rapid sequence intubation.
0.6-1.2 mg/kg in appropriately premedicated and adequately anesthetized clients will result in good intubating conditions in less than 2 min.
Tracheal intubation.
Initial, regardless of anesthetic technique: 0.6 mg/kg. Maximum blockade is noted in less than 3 min with a mean duration of 31 min. However, a dose of 0.45 mg/kg may also be used with maximum blockade in less than 4 min with a mean duration of 22 min. Initial doses of 0.6 mg/kg in children under halothane anesthesia produce good intubating conditions within 1 min with a mean duration of 41 min in children 3 months to 1 year and 27 min in children 1-2 years of age. Maintenance doses in children of 0.075-0.125 mg/kg, given upon return of T
1 of 25% of control provide muscle relaxation for 7-10 min.
Maintenance doses.
0.1, 0.15, and 0.2 mg/kg, given at 25% recovery of control T
1 (defined as three twitches of train-of-four), provide a median of 12, 17, and 24 min of duration under opioid/nitrous oxide/oxygen anesthesia. Do not adminiser the dose until recovery of neuromuscular function is evident.
Continuous infusion.
Initial: 0.01-0.02 mg/kg/min only after early evidence of spontaneous recovery from an intubating dose. Upon reaching the desired level of neuromuscular blockade, the infusion must be individualized for each client; adjust the rate based on the twitch response (monitored with the use of a peripheral nerve stimulator) of the client.
Maintenance, usual: 0.004-0.016 mg/kg/min.
