3. Old stuff
          3.1. Old pharm stuff (pre 2009)
              3.1.3. Pharmacology
                  3.1.3.7. Neuromuscular blocking drugs
                      3.1.3.7.2. Non-depolarising NMBDs
 3.1.3.7.2.1. Long-acting nondepolarising NMBDs 

Long-acting nondepolarising NMBDs

[SH4:p228-231]

  • Pancuronium is the most commonly used long-acting nondepolarising NMBDs
  • Doxacurium and pipecuronium are like pancuronium
    * But does not have CVS side effects like pancuronium

Doxacurium

  • A benzylisoquinolinium nondepolarising NMBD
  • ED95 = 30mcg/kg
    * c.f. pancuronium's ED95 = 70mcg/kg
  • Intubating dose = 0.05 mg/kg
    * [CEACCP 2004 Vol 4(1) "Pharmacology of neuromuscular blocking drugs"]
  • Onset of action = 4-6 minutes
    * Slow
    * c.f. pancuronium 3-5 minutes
  • Duration of NMJ blockade = 60-90 minutes
    * Long
    * Same as pancuronium
  • Does not have CVS effects like pancuronium
    * No histamine release

Pipecuronium

  • A bisquaternary aminosteroid nondepolarising NMBD
  • ED95 = 50mcg/kg
  • Onset of action = 3-5 minutes
  • Duration of NMJ blockade = 60-90 minutes
  • But hepatic cirrhosis does not seem to alter the pharmacokinetics or pharmacodynamics of pipecuronium

Pipecuronium vs pancuronium

  • Pipecuronium was similar to pancuronium in:
    * Structure
    * Pharmacokinetics (e.g. onset of action and duration)
    * Dependence on renal clearance
  • In contrast to pancuronium, pipecuronium was:
    * More potent
    * No vagolytic or sympathomimetic effects

Tubocurarine

[CEACCP 2004 Vol 4(1) "Pharmacology of neuromuscular blocking drugs"]

  • Long onset of action
  • Prolonged duration
  • Marked histamine release
    --> Pronounced hypotension and tachycardia
  • In large doses
    --> May produce ganglion block