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Non-Depolarizing Agents

A. Steroidal compounds B. Benzylisoquinolinium compounds C. Other Group
1. Pancuronium 1. Tubocurare 1. Gallamine
2. Vecuronium 2. Metocurine 2. Alcuronium
3. Pipecuronium 3. Doxacurium  
4. Rocuronium 4. Atracurium  
  5. Mivacurium  
Differences between two group-
A. Steroidal compounds B. Benzylisoquinolinium compound
1. Does not release histamine so no hypotension, tachycardia or flushing 1. Releases histamine so can produce hypotension, tachycardia or flushing
2. Metabolism through renal or hepatic 2. Unique metabolism
All neuromuscular blocker can have faster action if increased dose is administered.


  1. Named because it was transported in bamboo tube & used as arrow poison by Amazon people
  2. Dose - 0.5 mg / kg
  3. All excreted unchanged
  4. Maximum propensity for releasing Histamine
  5. Maximum propensity for ganglion blockade because of these 2 effects causes severe hypotension which can be reversed by calcium
  6. Resp. Bronchospasm (histamine release)
  7. Drug strongly concentrated in heart muscles
  8. Duration of effect - 40-60 min.


  1. Semisynthetic derivative of d- Tubocurare with less cardiovascular effects


  1. Max. Propensity for vagal blockade, so causes tachycardia
  2. Excreted unchanged (80%)
  3. Dose 1-2 mg/kg, Duration - 30-40 min.
  4. Allergic reactions common
  5. C/I --> Renal failure


  1. Anaphylaxis very common
  2. Deterioration on exposure to sunlight


  1. Steroid compound
  2. Dose - 0.08 mg /kg
  3. Half Life - 90 - 120 min
  4. Duration of effect - 30-40 min.
  5. Metabolism - only 10% is metabolized 25% is excreted in bile, So cautious use in biliary obstruction & renal diseases 80 % is bound to plasma proteins
  6. Effects: It cause sympathetic stimulation there by causing release of Noradrenaline & adrenaline, so causes tachycardia & increase BP intraoperatively.
  7. Relaxant of choice in arterial surgeries where BP maintenance is required
  8. Increases Chances of arrhythmia with halothane


  1. It has 2 ring A & D (D similar to pancuronium)
  2. Dose - 0.1 mg/kg
  3. Duration - 15-20 min.
  4. t 1/2 - 20 - 30 min.
  5. Metabolism: 30-40% metabolized in liver & rest excreted unchanged, produces a metabolite des vecuronium which can lead to polyneuropathy
  6. Significant amount excreted in bile
  7. Effect: CVS - stable


  1. Available as Atracurium Besylate
  2. Dose - 0.5 mg / kg
  3. Duration - 15 -20 min.
  4. t 1/2 - 20 min
  5. Metabolism: metabolized by Hoffman degradation (95%) in plasma & ester hydrolysis (5%)
  6. Metabolism produces laudanosine which crosses blood brain barrier& can produce convulsions (AIPG 07) & ↑ in MAC of halothane.
    1. Releases histamine but in significant amount at clinical doses
    2. Allergic reactions ranging from pruritic rash to angioneurotic edema can occur
  7. It is relaxant of choice in
    1. Renal failure
    2. Hepatic failure
    3. Patients with atypical pseudocholinesterase
    4. Myasthenia gravis (1 / 10th of normal dose)
    5. Small children


  1. It is a neuromuscular blocking drug or skeletal muscle relaxant in the category of non-depolarizing neuromuscular-blocking drugs, used adjunctively in anesthesia to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation.
  2. It is a bisbenzyltetrahydroisoquinolinium agent with an intermediate duration of action. Cisatracurium is one of the ten isomers of the parent molecule, atracurium.Moreover, cisatracurium represents ~15% of the atracurium mixture.
  1. Pharmacology
    1. As is evident with the parent molecule, atracurium cisatracurium is also susceptible to degradation by Hofmann elimination and ester hydrolysis as components of the in vivo metabolic processes.
    2. Because Hofmann elimination is a temperature- and plasma pH-dependent process, cisatracurium's rate of degradation in vivo is highly influenced by body pH and temperature just as it is with the parent molecule, atracurium: thus, an increase in body pH favors the elimination process, whereas a decrease in temperature slows down the process
    3. One of the metabolites of cistracurium via Hofmann elimination is laudanosineQ-
    4. 80% of cisatracurium is metabolized eventually to laudanosine and 20% is metabolized hepatically or excreted renally. 10-15% of the dose is excreted unchanged in the urine.
    5. Since Hofmann elimination is an organ-independent chemodegradative mechanism, there is little or no risk to the use of cisatracurium in patients with liver or renal disease when compared with other neuromuscular blocking agents.
  2. Adverse effects
    • Histamine release - hypotension, reflex tachycardia and cutaneous flush
      • Unlike the parent, atracurium, cisatracurium affords a much better pharmacological profile with respect to eliciting histamine release.
  3. Bronchospasm - Pulmonary compliance
    To date, cisatracurium has not been reported to elicit bronochospasm at doses that are clinically prescribed.
  4. Laudanosine - Epileptic foci
    1. Cisatracurium undergoes Hofmann elimination as a primary route of chemodegradation: consequently one of the metabolites from this process is laudanosine, a tertiary amino alkaloid reported to be a modest CNS stimulant with epileptogenic activity and cardiovascular effects such a hypotension and bradycardia.
    2. As a tertiary amine, Laudanosine is unionised and readily crosses the blood-brain barrier.
    3. Presently, there is little evidence that laudanosine accumulation and related toxicity will likely ever be seen with the doses of cisatracurium that are administered in clinical practice especially given that the plasma concentrations of laudanosine generated are lower with cisatracurium than those seen with atracurium.
Difference between cisatracurium and atracurium
  1. Cisatracurium is a stereoisomer of atracurium
  2. Cisatracurium is four times more potent than atracurium
  3. Metabolism of both atracurium and cisatracurium produces laudanosine as metabolite but cisatracurium produces very less amount metabolite.
  4. Atracurium is also metabolised by alternative pathway by nonspecific esterase.
  5. Histamine release is very less by cisatracurium.


  1. Benzylisoquinoline diester metabolized by pseudocholinesterase
  2. Dose: 0.3 mg/kg
  3. Duration of action: 5-10 min.
  4. S/E: histamine release, So it can cause Bronchospasm, Flushing, Hypotension (AIIMS Nov 07)
    ​ Relaxants do not cross blood brain barrier & placenta in significant amounts (NDMR) so can be given safely.


  1. Benzylisoquinoline with no histamine & vagolytic properties so CVS stable.
  2. Least rapid onset and longest duration of action (60-120) eve longer than pipecuronium (10-100min)
  3. Most potent
  4. Dose - 0.06 mg /kg


  1. It is pancuronium derivative.
  2. No vagolytic or ganglion blockade action so cardiovascular stable.
  3. Dose - 0.8 mg/kg,
  4. Duration of block = 60 to 120 min.


Chemical structure
  1. An amino steroid which is structurally related to vecuronium. 8 times less potent than vecuronium. Onset of action 60 sec. (if to vec. 2-3 min.)
  2. Presentation: As a clear solution containing 10 mg/ml. Available in 5 ml and 10 ml ampoules.
  3. Cardiovascular effects
    Minimal; with large doses, a mild vagolytic effect leads to a slight increase in heart rate and mean arterial pressure.
  4. Respiratory effects
    No significant histamine release. Bronchospasm is extremely uncommon.
  5. Distribution, metabolism and excretion
    1. Rocuronium is 30% protein bound in the plasma. No metabolites have been detected in plasma or urine. Ii. Excreted primarily by hepatic uptake and hepatobiliary excretion. The pharmacokinetics are not significantly altered in renal failure.
  6. Dose, administration and use
    1. Rocuronium is administered intravenously. The normal intubating dose is 0.6 mg/kg, with subsequent doses of one quarter this amount. The drug is non-cumulative with repeated administration. In animal studies, Rocuronium does not appear to be a triggering factor for malignant hyperthermia.
    2. Dosage and duration
      Dose (mg/kg) Duration (minutes) Intubation (seconds)
      0.3 - 0.45 13 - 26 120
      0.6 30 - 40 60
      0.9 53 45 
    3. Storage: 3 years - between , 2-8 degrees C or 3 months - below 30 degrees C
Current discussions Rocuronium
  1. Anaphylaxis is very rare with Rocuronium.
  2. Use of Rocuronium in rapid sequence induction
    1. The principal reason for the continuing use of succinylcholine, the rapid recovery of maternal neuromuscular function in the event of an airway crisis, was never originally considered potentially advantageous.
    2. The estimated incidence of serious reaction to succinylcholine is 1:4000 inductions.
    3. Anaphylaxis to succinylcholine has been responsible for maternal deaths at Caesarean section, and many near misses.
    4. Rocuronium 0.6 mg/kg is licensed for Caesarean section and has been shown to produce acceptable intubating conditions after Thiopental 6 mg/kg within 90 seconds. Unlike the case with succinylcholine in failed intubation, optimal conditions for airway management and maintaining oxygenation will be sustained and vomiting cannot occur.
    5. Maintenance of a slight head up tilt should allow gravity to reduce the risk of reflux of gastric contents. In the most unlikely event of airway obstruction at the glottis causing a ‘can’t intubate, can’t ventilate’ scenario, the best chance of successful
    6. cricothyrotomy will be afforded by profound neuromuscular block.

Rapacuronium (May AIIMS 2008)

  1. This is less potent than other amino steroid agents such as rocuronium and vecuronium.
  2. Intubating dose of rapacuronium is 1.5 mg/kg.
  3. Complete onset of block in 55-70s .
  4. Repeat administration of rapacuronium, or administration by continuous infusion, is associated with more prolonged block, possibly due in part to accumulation of active metabolites .
  5. It causes dose-dependent increases in heart rate and decreases in arterial blood pressure .
  6. Its administration has been associated with histamine release, and other factors may be involved .
  7. Erythema, bronchospasm occurs.
5W 89
  1. It is stereoisomer of Atracurium with no histamine release.

ORG 9487

  1. Steroid relaxant with very early onset (83 sec)

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