Rocuronium

Class

Rocuronium is a non-depolarizing steroidal muscle relaxant of intermediate duration. However, onset may be rapid or intermediate depending on the injected dose.

History

Rocuronium was introduced into clinical practice in 1994

Chemical Structure

Rocuronium lacks the acetyl ester that is found in the A-ring of the steroid nucleus of pancuronium and vecuronium. The introduction of cyclic substituents other than piperidine at the 2 and 16 positions results in a compound with a, more rapid onset of effect than vecuronium or pancuronium. The methyl group attached to the quaternary nitrogen of vecuronium and pancuronium is replaced by an allyl group in rocuronium. As a result of this change, rocuronium is approximately 6 and 10 times less potent than pancuronium and vecuronium, respectively.

Formula: C32H53BrN2O4

Rocuronium

Formulation and Administration

  • Sterile, Non-pyrogenic, isotonic solution that is clear, colorless to yellow/orange
  • Preparations: 5/10 ml ampoules containing 10 mg/ml of Rocuronium for Intravenous administration only
  • Storage at 2°C - 8°C; Do not freeze
  • After removal from refrigeration to room temperature, use within 60 days
  • Opened vials to be used within 30 days

Compatable in solution with:

  • 0.9% NaCl solution
  • 5% glucose in water
  • 5% glucose in saline
  • Sterile water for injection
  • Lactated Ringers
  • 24 hours at room temperature in plastic bags, glass bottles, and plastic syringe pumps

Never mixed with alkaline solutions

Mechanism of Action

  • Rocuronium is a nondepolarising muscle relaxant, and acts by competitive antagonism of acetylcholine at nicotinic (N2) receptors at the motor end-plate. Has some additional pre-junctional action
  • Its action is antagonized by acetylcholinesterase inhibitors, such as neostigmine.
  • Sugammadex is a specific agent used to antagonise the actions of Rocuronium and other amino-steroid muscle relaxants to lesser extent.

Pharmacokinetics

  • Time to Maximum Block: 1.7 min
  • Clinical Duration of response: 36 Minutes
  • Distribution: Moderately protein bound; the drug has a Vd of 0.207 L/Kg. The drug does not cross the blood brain barrier. Crosses placenta, but not in clinically significant amounts
  • Metabolism: 17-desacetylrocuronium (minimal in quantity)
  • Excretion: Rocuronium is excreted primarily by hepatic route (70%)
    • Unchanged drug is also excreted in the urine (30%).
    • The elimination of Rocuronium is extended by 30 Minutes in the presence of hepatic failure and is not affected by renal failure

Pharmacodynamics

  • Rocuronium is cardiostable drug and does not alter haemodynamics. However, when given in doses above 1 mg/kg it can cause tachycardia due to its mild vagolytic effects.
  • It does not cause histamine release.

Dosage

  • For Tracheal Intubation 0.45 to 0.6 mg/kg; provides 22 to 31 minutes of relaxation
  • For Rapid Sequence Intubation 0.9 to 1.2 mg/kg; provides intubating conditions in most patients in less than 2 minutes
  • Supplemental Dose after intubation is 0.1 - 0.2 mg/kg, and it provides relaxation for 12-17 minutes
  • Continuous infusion dosage (pg/kg/min) required to maintain 90%-95% twitch inhibition under N2O/O2 with intravenous agents: 9-12 mcg/Kg/min
  • Not used for long-term use in the ICU
  • Very low dose in patients with Myasthenia gravis

Adverse Effects

  • Transient hypotension or hypertension
  • Residual paralysis
  • Increased Pulmonary Vascular Resistance
  • Bronchospasm or Rhonchi, Hiccup
  • Arrhythmia and Tachycardia
  • Injection site edema, or Pruritus
  • Myopathy
  • Nausea or Vomiting
  • Light-headedness
  • Anxiety and Confusion
  • If extravasation occurs then severe local irritation
  • Anaphylactoid reactions have been reported with Rocuronium

Contraindications

  • Hypersensitivity to Rocuronium
  • Severe Hepatic failure

Special Points

  • The duration of action of Rocuronium is increased by hypokalaemia, hypocalcemia, hypermagnesemia, acidosis and dehydration.
  • Drugs such as inhalational agents, induction agents, diuretics, Alpha- and beta-adrenergic blocking agents, Calcium channel blockers, Protamine, Metronidazole, Lignocaine, and Aminoglycoside antibiotics cause increase in the effect of Rocuronium.
  • Sugammadex specifically reverses the effects of Rocuronium by forming a complex. This is especially useful if a "cannot ventilate cannot intubate" (CVCI) situation occurs after giving Rocuronium for Intubation.
  • Rocuronium is one of the main drug for execution by lethal injections in USA and other countries

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