Neuromuscular blocking agents: Difference between revisions

Latest revision as of 00:47, 25 February 2020

Background

Non-depolarizing
- Competitively block binding of ACh to its receptors
Depolarizing
- Depolarizing skeletal muscle fiber
- Persistent depolarization makes the muscle fiber resistant to further stimulation by ACh

Types

Neuromuscular Blocking Agents
Agent	Time to onset (seconds)	Duration (minutes)	Side effects
Depolarizing
Succinylcholine			fasciculations, post-operative pain
Non-Depolarizing
Vecuronium (Norcuron)	60	30–40	Few, may cause prolonged paralysis and promote muscarinic block
Rocuronium (Zemuron)	75	45–70	may promote muscarinic block
Pancuronium (Pavulon)	90	180 or more	tachycardia (slight) (no hypotension)

References

Authors:

@@ Line 1: / Line 1: @@
 ==Background==
-These drugs fall into two groups:
+*'''Non-depolarizing'''
+**Competitively block binding of ACh to its receptors
-*'''Non-depolarizing blocking agents''': These agents constitute the majority of the clinically relevant neuromuscular blockers.  They act by competitively blocking the binding of ACh to its receptors, and in some cases, they also directly block the [[ionotropic]] activity of the ACh receptors.<ref name="pmid8866353">{{cite journal |author=Bufler J, Wilhelm R, Parnas H, Franke C, Dudel J |title=Open channel and competitive block of the embryonic form of the nicotinic receptor of mouse myotubes by (+)-tubocurarine |journal=J. Physiol. (Lond.) |volume=495 ( Pt 1) |issue= Pt 1|pages=83–95 |year=1996 |pmid=8866353 |doi= |pmc=1160726}}</ref>
+*'''Depolarizing'''
+**Depolarizing skeletal muscle fiber
-*'''Depolarizing blocking agents''': These agents act by [[Depolarization|depolarizing]] the [[sarcolemma]] of the skeletal [[muscle fiber]]. This persistent depolarization makes the muscle fiber resistant to further stimulation by ACh.
+**Persistent depolarization makes the muscle fiber resistant to further stimulation by ACh
 ==Types==
@@ Line 10: / Line 10: @@
 |+Neuromuscular Blocking Agents
 !Agent
-|'''Time to onset''' <br> (seconds)
+!'''Time to onset''' (seconds)
-|'''Duration''' <br> (minutes)
+!'''Duration''' (minutes)
 !Side effects
-!Clinical use
 |-
-| '''Non-Depolarizing'''
+| '''Depolarizing'''
 |-
 |[[Succinylcholine]]
 |
 |
-|
+|fasciculations, post-operative pain
-|
 |-
-| '''Depolarizing'''
+| '''Non-Depolarizing'''
-|-
-|[[Atracurium]] (Tracrium)
-|90
-|30 min or less<ref name=Rang151/>
-|
-*[[hypotension]], transiently,<ref name=Rang151/> by release of histamine
-*Toxic metabolite called [[laudanosine]], greater accumulation in individuals with renal failure
-|widely<ref name=Rang151/>
-|-
-|[[Cisatracurium]] (Nimbex)
-|90
-|60–80
-|does not cause release of histamine
-|
 |-
 |[[Vecuronium]] (Norcuron)
 |60
-|30–40<ref name=Rang151/>
+|30–40
-|Few,<ref name=Rang151/> may cause prolonged paralysis<ref name=Rang151/> and promote muscarinic block
+|Few, may cause prolonged paralysis and promote muscarinic block
-|widely<ref name=Rang151/>
 |-
 |[[Rocuronium]] (Zemuron)
 |75
-|45–70{{Citation needed|date=March 2010}}
+|45–70
 |may promote muscarinic block
-|
 |-
 |[[Pancuronium]] (Pavulon)
 |90
-|180 or more{{Citation needed|date=March 2010}}
+|180 or more
 |
-*[[tachycardia]] (slight)<ref name=Rang151/>
+*[[tachycardia]] (slight)
-(no hypotension)<ref name=Rang151/>
+*(no [[hypotension]])
-|widely<ref name=Rang151/>
 |-
 |}
-==Comparison of Drugs ==
+==See Also==
-The main difference is in the reversal of these two types of neuromuscular-blocking drugs.
+*Reversal agent: [[Sugammadex]]
-* Non-depolarizing blockers are reversed by [[acetylcholinesterase inhibitor]] drugs since they are competitive antagonists at the ACh receptor so can be reversed by increases in ACh.
-* The depolarizing blockers already have ACh-like actions, so these agents have prolonged effect under the influence of acetylcholinesterase inhibitors. Administration of depolarizing blockers initially produces ''fasciculations'' (a sudden twitch just before paralysis occurs). This is due to depolarization of the muscle. Also, post-operative pain is associated with depolarizing blockers.
-==Sources==
+==References==
 <references/>
+[[Category:Pharmacology]]
+[[Category:Critical Care]]