4 Non Depolarizing Muscle Relaxants (NDMR)

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Non Depolarizing Muscle Relaxants (NDMR) :

• No Muscle fassiculation.

• Slow onset and slow dissociation.

• Reversed by Neostigmine.

• Muscle remains responsive to other stimulus (Therefore Neuromuscular monitor used).

• Fade & Post tetanic stimulation.

• Mild hypothermia antagonizes block.

Atracurium :

• Metabolism - 75% by Hoffman degradation, 25 % by  ester hydrolysis.
• Metabolite - Laudanosine (pro convulsant)
• Does not require any reversal agent

• DOC in :

1. Renal and Hepatic failure cases.
2. Myesthenia Gravis - Use 1/10 th of normal dose

CisAtracurium :

• 3 times more potent
• No histamine release
• Non cumulative
• Only Hoffman degradation
• Laudanosine levels are lower.

Mivacurium :

• Ultra Short
• Metabolism - Plasma Cholinesterase (=Pseudo)
• Ideal Muscle relaxant for Continuous infusion , day care surgery.

Doxacurium :

• Most Potent
• Long acting
• Metabolism - Kidney

D Tubocurarine :

• Long acting 
• Cause hypotension by ganglionic block

Vecuronium Bromide :

• Most Haemodynamically stable
• Minimum Vagolytic
• Metabolism - Liver

Pancuronium :

• Causes Hypertension and tachycardia (therefore good in Shock)
• Long acting
• Vagolytic
• Causes Nor-epinephrine release

Rocuronium bromide :

• Rapid onset (therefore can be used in full stomach)
• Slightly vagolytic
• Largely excreted unchanged in bile

Pipecuronium :

• Longest acting
• No vagolytic activuty

Rapacuronium :

• Fastest Onset (among NDMR) ( Note: Overall Fastest Onset Muscle relaxant is Sch )
• Increases incidence of bronchospasm.

Gallamine:

• Maximum propensity for vagal blockade
• Cross Placenta (therefore contraindicated in Pregnancy)
• Also Contraindicated in Renal disease.

Alcuronium :

• Anaphylaxis is common
• Deterioration on exposure to sunlight.

Fastest onset agents are used in full stomach : (preference order as mentioned below)

1. Succinylcholine
2. Rapacuronium
3. Rocuronium

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