Neuromuscular blocking agents

Chapter 18:  Neuromuscular Blockers

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Neuromuscular Blocking Drugs

Skeletal Muscle Relaxants

Spasmolytic agents

Anti--Spasmolytic Drugs
  • baclofen (Lioresal)

  • botulinum toxin type A (Botox)

  • carisoprodol (Soma, Rela)

  • chlorphenesin (Maolate)

  • chlorzoxazone (Paraflex,generic)

  • cyclobenzaprine (Flexeril)

  • dantrolene (Dantrium)

  • diazepam (Valium)

  • metaxalone (Skelaxin)

  • methocarbamol (Robaxin)

  • orphenadrine (Norflex)

  • tizanidine (Zanaflex)

 

Katzung, B.G.., Skeletal Muscle Relaxants, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 434-449;White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996

 

Neuromuscular Blocking Agents

Overview-Neuromuscular Blocking Drugs

NMJ blockers: Isoquinoline derivatives

NMJ blockers: Isoquinoline derivatives, Atracurium (Tracrium)

NMJ blockers: Isoquinoline derivatives,  Mivacurium (Mivacron)

 

Other NMJ blockers

NMJ blockers: Steroid derivatives,  Pancuronium (Pavulon)

NMJ blockers: Depolarizing blocker  Succinylcholine (Anectine) 

 

Pharmacokinetics: Neuromuscular Blocking Drugs

Nondepolarizing agents --Elimination characteristics

Isoquinoline derivatives

Drug

Elimination mechanism

Duration of action (minutes)

Atracurium (Tracrium)

ester hydrolysis (enzymatic & nonenzymatic)

20-35

Cisatracurium (Nimbex)

spontaneous (Hoffmann elimination)

25-44

Doxacurium (Nuromax)

renal

> 35

Metocurine (Metubine Iodide)

renal (40%)

> 35

Mivacurium (Mivacron)

plasma pseudocholinesterase

10-20

Tubocurarine

renal (40%)

> 35

 

Steroid Derivatives

Drug

Elimination mechanism

Duration of action (minutes)

Pancuronium (Pavulon)

renal (80%)

> 35

Pipecuronium (Arduan)

renal (60%) & hepatic

> 35

Rocuronium (Zemuron)

hepatic (75-90%) & renal

20-35

Cecuronium (Norcuron)

hepatic (75-90%) & renal

20-35

 

Other Drugs of Interest

Drug

Elimination mechanism

Duration of action (minutes)

gallamine (Flaxedil)

renal (100%)

> 35

succinylcholine (Anectine)

plasma pseudocholinesterase

< 8

*-- adapted from Table 27-1: Miller, R.D., Skeletal Muscle Relaxants, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, p. 438

Introductory comments about specific Nondepolarizing agents

NMJ blockers: Steroid derivatives,  Vecuronium (Norcuron)

NMJ blockers: Steroid derivatives,  Pancuronium (Pavulon)

Depolarizing Neuromuscular Blocking Agents

 

Pharmacodynamics

"The orbicularis oculi is the thin sphincter muscle of the eyelids. It is
innervated by temporal and zygomatic branches of the facial nerve.", Image courtesy of Vesalius, used with permission

Adductor Pollicis

Image courtesy of EatonHand (http://www.eatonhand.com/mus/mus005.htm)

Cricothyroid Muscle

Cricothyroid Muscle: Vesalius Site, used with permission

Clinical Uses

Miller, R.D., Skeletal Muscle Relaxants, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 434-449. Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219. White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

 

Depolarization Neuromuscular Blockade

Succinylcholine (Anectine)

Miller, R.D., Skeletal Muscle Relaxants, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 434-449. Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219 White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Masseter Jaw Anatomy

 "The Structural and Functional Anatomy of Mastication" by Paul Surtees, B.Sc; The Victoria University of Manchester (1999)

Miller, R.D., Skeletal Muscle Relaxants, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 434-449; .Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Non-depolarizing Blocking Drugs

Table of Contents

Factors which alter patient responses to nondepolarizing agents

Drugs

diuretics

ganglionic blocking agents

magnesium

aminoglycoside antibiotics

local anesthetics

volatile anesthetics

antiarrhythmic agents

lithium

 

Other Factors Influencing Responses to Nondepolarizing Agents

hypotension

altered serum potassium

adrenocortical abnormality

burned injury

allergic reactions

abnormal acid-base balance

Gender may also influence duration of action;  combinations of nondepolarizing neuromuscular-blocking agents may result in different effects than agents used separately

Some aminoglycosides
  •  Streptomycin
  •  Gentamicin (Garamycin)
  •  Tobramycin (Nebcin)
  •  Amikacin (Amikin)
  •  Kanamycin (Kantrex)& Neomycin
  •  Spectinomycin (Trobicin)

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996; Miller, R.D., Skeletal Muscle Relaxants, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 434-449.

Clinical Pharmacology

Role of neuromuscular blockade in anesthesia.

Reversal of non-depolarizing blockers: Antagonist-assisted reversal of neuromuscular blockade produced by nondepolarizing neuromuscular-blocking agents

Stoelting, R.K., "Anticholinesterase Drugs and Cholinergic Agonists", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, 224-237.

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219

Some Neuromuscular blocking drugs

 

 

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219;  White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Introduction: Intermediate-acting Nondepolarizing Blockers

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219;  White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

Short-acting nondepolarizing neuromuscular blocker: Mivacurium (Mivacron)

Stoelting, R.K., "Neuromuscular-Blocking Drugs", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 182-219; White, P. F. "Anesthesia Drug Manual", W.B. Saunders Company, 1996.

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