Rocuronium

Rocuronium

Indication

• Used to produce skeletal muscle relaxation/paralysis in neonates  in the NICU who are mechanically ventilated, asynchronous  and are still in respiratory failure in spite of sedation

Pharmacology

• Rocuronium competes with acetylcholine for receptor sites on the postjunctional membrane, thereby interrupting transmission of nerve impulses at the neuromuscular junction
• It is a non-depolarizing agent; this means that muscular paralysis can be reversed if the concentration of acetylcholine is increased, by using an anticholinesterase inhibitor such as neostigmine, edrophonium or pyridostigmine
• In preterm infants, especially those with acidosis, hypothermia or hypotension, consideration should be given to a lower initial dose during the first week of life
• Primarily biliary excretion (70%); up to 30% of dose excreted unchanged in urine thus no dosage adjustment needed for renal dysfunction but hepatic dysfunction may prolong neuromuscular blockade
• Onset of clinical effect usually seen within 2 minutes and duration ranges from 20 minutes to 2 hours (larger doses have more rapid onset and longer duration of action)

Side Effects

• Tachycardia, arrhythmias and changes in blood pressure (both hypotension and hypertension)
• Hypersensitivity reactions, bronchospasm (rare)
• Transient rash, residual muscle weakness, prolonged dose-related apnea
• In respiratory failure in the neonate, in approximately 1/3 of patients PaO2 will improve, in 1/3 PaO2 will remain the same, and in 1/3 PaO2 will worsen; therefore, close attention must be given to respiratory settings and FiO2

Nursing Implications

• Once the infant receives rocuronium, dramatic changes in the respiratory settings may be necessary
• Aminoglycoside antibiotics (e.g. gentamicin) and vancomycin potentiate neuromuscular blockage, leading to increased skeletal muscle relaxation
• Opiates can cause CNS respiratory depression which can add to the respiratory depressant effects of rocuronium
• Monitor baseline electrolyte values since electrolyte imbalance can potentiate neuromuscular effects (hypokalemia, hypermagnesemia)
• Respiration, heart rate and blood pressure should be monitored continuously
• Mechanical ventilation is a prerequisite to using rocuronium
• Must have constant nursing observation
• Give eye care every 30-60 minutes; use methylcellulose 0.5% solution to keep eyes lubricated, apply eye pad covers
• Measure liver function tests as hepatic dysfunction may prolong duration of action
• Store rocuronium in refrigerator; do not store in plastic containers or syringes, although plastic syringes may be used for administration; use only fresh solutions
• Blood gases must be done 20-30 minutes after first dose or baby must be on continuous CO2 monitoring
• Observe the infant for return of skeletal muscle activity and consult the physician regarding further drug administration

Dose of Rocuronium for Paralysis

• 0.3 to 0.6 mg/kg/dose, every 30min PRN, start at lower end of dosing as duration of action is dose dependent

• If paralysis is to continue beyond a few hours, should be given as a continuous infusion: 7 to 10mcg/kg/min
• Dose depends on individual needs and response and must be adjusted accordingly
• For continuous infusion, dilute with normal saline, 5% dextrose in water or lactated ringers solution to a concentration of 0.5-1 mg/mL (24 hour stability)

Reversal of Neuromuscular Blockade

• Neuromuscular blockade can be reversed by administering a cholinesterase inhibitor such as neostigmine

Dose for Reversal Neuromuscular Blockade

• Give atropine prior to neostigmine, to prevent vagal reaction (bradycardia, bronchospasm, increased salivation)
• Atropine 0.02 mg/kg slow IV push by Physician only
• Neostigmine 0.06 mg/kg slow IV push by Physician only

Supplied As

• 10 mg/mL multidose 5mL vial (contains no preservatives), kept in refrigerator (if left out at room temperature, expiry of unpunctured vial is 90 days from date left out or expiry date of vial, whichever is shorter)
• Once punctured, vial should be used within 30 days and stored in the refrigerator as per the manufacturer
• Diluted solutions for infusion are stable for 24 hours