II. Precautions

  1. Used only in Anesthesia, emergency and Intensive Care
  2. Airway and Respiratory Control is critical after use
  3. Paralytic Agents do not alter Level of Consciousness
    1. Must be used with sedation and analgesia

III. Mechanism

  1. Interfere with transmission at neuromuscular end plate
  2. Two mechanisms of Neuromuscular Blockade
    1. Non-depolarizing agents (AcetylcholineAntagonists)
      1. Prototype: Curare
      2. Agents used clinically
        1. Rocuronium (Rapid Sequence Intubation)
        2. Vecuronium
        3. Pancuronium
      3. Other agents: Tubocurarine, Metocurine, Gallamine
      4. Paralysis progression
        1. Paralysis of small Muscles (eyes, fingers)
        2. Paralysis of extremities, neck and trunk
        3. Paralysis of intercostal Muscles and diaphragm
    2. Depolarizing agents (AcetylcholineAgonists)
      1. Cholinergic Agonists that block Acetylcholine from binding until they dissociate from receptor site
        1. Nerves depolarize (resulting in Fasciculations) prior to paralysis
        2. May also occur with Cholinesterase Inhibitors
      2. Prototype: Succinylcholine
      3. Agents used clinically
        1. Succinylcholine (Rapid Sequence Intubation)
      4. Paralysis progression
        1. Chest and abdomen Fasciculations (depolarization)
        2. Paralysis of neck, arms and legs
        3. Paralysis of face, pharynx and Larynx
        4. Paralysis of respiratory Muscles

IV. Monitoring: Neuromuscular Blockade (Paralytic Depth)

  1. Train of Four
    1. Peripheral Nerve stimulator delivers 4 impulses over 2 seconds
    2. Muscle Twitch response
      1. 1 Twitch indicates sufficient relaxation with nitrous and Opioids
      2. 3 Twitches indicate sufficient relaxation with inhalational agents
      3. 4 twitches (with 4th at least 75% of the first) indicates readiness for Extubation
  2. Sustained Tetany
    1. Peripheral Nerve stimulator delivers a sustained 5 second impulse at 50 Hz
    2. Muscle Twitch response indicates patient is ready for Extubation
  3. Single Stimulation
    1. Peripheral Nerve stimulator delivers a single 0.2 mSec 0.1 Hz stimulation
    2. Muscle Twitch response <5% of normal twitch indicates readiness for Endotracheal Intubation

V. References

  1. Miller in Katzung (1989) Pharmacology, p. 323-33
  2. Savarese in Miller (2000) Anesthesia, p. 412-90

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Related Studies

Ontology: Neuromuscular Nondepolarizing Agents (C0010464)

Definition (MSH) Drugs that interrupt transmission at the skeletal neuromuscular junction without causing depolarization of the motor end plate. They prevent acetylcholine from triggering muscle contraction and are used as muscle relaxants during electroshock treatments, in convulsive states, and as anesthesia adjuvants.
Concepts Pharmacologic Substance (T121)
MSH D003473
SnomedCT 135396007
English Agents, Curare-Like, Agents, Neuromuscular Nondepolarizing, Curare Like Agents, Curare-Like Agents, Curariform Drugs, Drugs, Curariform, Muscle Relaxants, Non Depolarizing, Muscle Relaxants, Non-Depolarizing, Neuromuscular Nondepolarizing Agents, Nondepolarizing Agents, Neuromuscular, Neuromuscular Blocking Agents, Competitive, Non-Depolarizing Muscle Relaxants, Blockers, Nondepolarizing, Nondepolarizing Blockers, Non-depolarising muscle relax., Non-depolarising muscle relaxant, Non-depolarizing muscle relax., Non-depolarizing muscle relaxant, Non-depolarizing muscle relaxant (product), Curare-like agents, Non-depolarizing muscle relaxant (substance)
French Curarisants non dépolarisants, Curarisants acétylcholinocompétitifs, Myorelaxants non dépolarisants, Curarisants acétylcholino-compétitifs, Inhibiteurs neuromusculaires non dépolarisants
Swedish Neuromuskulära icke-depolariserande medel
Czech nervosvalové látky nedepolarizující, myorelaxancia nedepolarizující, kurareformní látky
Finnish Ei-depolarisoivat lihasrelaksantit
Russian KURAREPODOBNYE SREDSTVA ANTIDEPOLIARIZUIUSHCHIE, NERVNOMYSHECHNYE NEDEPOLIARIZUIUSHCHIE SREDSTVA, KURAREPODOBNYE SREDSTVA NEDEPOLIARIZUIUSHCHIE, MIORELAKSANTY NEDEPOLIARIZUIUSHCHIE, NEDEPOLIARIZUIUSHCHIE MIORELAKSANTY, PAKHIKURARE, PREPARATY KURARE, NERVNO-MYSHECHNYE NEDEPOLIARIZUIUSHCHIE SREDSTVA, KURAREPODOBNYE SREDSTVA, КУРАРЕПОДОБНЫЕ СРЕДСТВА, КУРАРЕПОДОБНЫЕ СРЕДСТВА АНТИДЕПОЛЯРИЗУЮЩИЕ, КУРАРЕПОДОБНЫЕ СРЕДСТВА НЕДЕПОЛЯРИЗУЮЩИЕ, МИОРЕЛАКСАНТЫ НЕДЕПОЛЯРИЗУЮЩИЕ, НЕДЕПОЛЯРИЗУЮЩИЕ МИОРЕЛАКСАНТЫ, НЕРВНО-МЫШЕЧНЫЕ НЕДЕПОЛЯРИЗУЮЩИЕ СРЕДСТВА, НЕРВНОМЫШЕЧНЫЕ НЕДЕПОЛЯРИЗУЮЩИЕ СРЕДСТВА, ПАХИКУРАРЕ, ПРЕПАРАТЫ КУРАРЕ
Italian Curarici, Rilassanti muscolari non depolarizzanti, Sostanze nondepolarizzanti del sistema neuromuscolare, Bloccanti neuromuscolari competitivi, Farmaci curariformi, Farmaci bloccanti neuromuscolari, Bloccanti non depolarizzanti, Sostanze curaro-simili, Sostanze non depolarizzanti del sistema neuromuscolare
Croatian NEUROMUSKULARNI BLOKATORI, NEDEPOLARIZIRAJUĆI
Polish Środki niedepolaryzujące działające na połączenie nerwowo-mięśniowe, Czynniki niedepolaryzujące nerwowo-mięśniowe, Środki kuraryzujące
Japanese 競合的遮断薬, 神経筋非脱分極剤, クラーレ様物質, クラーレ様薬物, 神経筋接合部興奮薬, 神経筋接合部非脱分極剤, 神経筋非脱分極薬, 競合的神経筋接合部遮断薬, 非脱分極性神経筋弛緩薬, 非脱分極性神経筋接分部遮断薬, 非脱分極性筋弛緩薬, 非脱分極性遮断薬, 非脱分極筋弛緩薬, クラーレ様薬剤, 神経筋弛緩薬-非脱分極性, 非脱分極性神経筋弛緩剤
Portuguese Fármacos Curariformes, Fármacos Similares ao Curare, Fármacos Neuromusculares não Despolarizantes, Drogas Curariformes, Agentes Semelhantes ao Curare, Agentes Curariformes, Agentes não Despolarizantes Neuromusculares, Bloqueadores Neuromusculares Competitivos, Relaxantes Musculares não Despolarizantes
Spanish Fármacos Similares al Curare, Fármacos Curariformes, Fármacos Neuromusculares no Despolarizantes, Bloqueantes Neuromusculares Competitivos, relajante muscular no despolarizante (producto), miorrelajante no despolarizante, relajante muscular no despolarizante, Agentes no Despolarizantes Neuromusculares, Bloqueadores Neuromusculares Competitivos, Drogas Curariformes, Agentes Curariformes, Relajantes Musculares no Despolarizantes
German Kurariforme Arzneimittel, Muskelrelaxantien, nicht-depolarisierende, Curare-ähnliche Substanzen, Neuromuskuläre Blocker, kompetitive, Neuromuskuläre nichtdepolarisierende Wirkstoffe

Ontology: Neuromuscular Blocking Agents (C0027866)

Definition (MSH) Drugs that interrupt transmission of nerve impulses at the skeletal neuromuscular junction. They can be of two types, competitive, stabilizing blockers (NEUROMUSCULAR NONDEPOLARIZING AGENTS) or noncompetitive, depolarizing agents (NEUROMUSCULAR DEPOLARIZING AGENTS). Both prevent acetylcholine from triggering the muscle contraction and they are used as anesthesia adjuvants, as relaxants during electroshock, in convulsive states, etc.
Definition (CSP) drugs that interrupt transmission of nerve impulses at the skeletal neuromuscular junction; they prevent acetylcholine from triggering muscle contraction and they are used as anesthesia adjuvants, as relaxants during electroshock, and in convulsive states.
Concepts Pharmacologic Substance (T121)
MSH D009466
SnomedCT 373295003, 87586001
English Agents, Neuromuscular Blocking, Blocking Agents, Neuromuscular, Neuromuscular Blocking Agents, neuromuscular blocking agent, Blockers, Neuromuscular, Neuromuscular Blockers, NEUROMUSCULAR BLOCK AGENTS, NEUROMUSCULAR BLOCKING AGENTS, neuromuscular blockers, neuromuscular blockers (medication), [MS300] NEUROMUSCULAR BLOCKING AGENTS, neuromuscular blocking agents, neuromuscular blocker, blockers neuromuscular, Neuromuscular blocking agents, Neuromuscular blocking agent, Neuromuscular blocking agent (product), Neuromuscular blocking agent (substance), Neuromuscular blocking agent, NOS, Neuromuscular Blocking Drugs
French Inhibiteurs neuromusculaires, Bloquants neuromusculaires, Curarisants, Agents curarisants, Médicaments curarisants, Curarimimétiques
Swedish Neuromuskulära blockerare
Czech nervosvalové blokátory
Finnish Hermo-lihasliitoksen salpaajat
Russian NERVNO-MYSHECHNYE BLOKATORY, НЕРВНО-МЫШЕЧНЫЕ БЛОКАТОРЫ
Japanese 神経筋遮断剤, 神経筋接合部伝達阻止物質, 神経筋接合部遮断薬, 神経筋遮断薬
Croatian Not Translated[Neuromuscular Blocking Agents]
Polish Środki miorelaksacyjne, Leki blokujące połączenia nerwowo-mięśniowe
Spanish Bloqueantes Neuromusculares, Agentes Bloqueadores Neuromusculares, Agentes Bloqueantes Neuromusculares, Bloqueadores Neuromusculares, agente bloqueante neuromuscular (producto), agente bloqueante neuromuscular (sustancia), agente bloqueante neuromuscular
German Neuromuskuläre Hemmstoffe
Italian Bloccanti neuromuscolari
Portuguese Bloqueadores Neuromusculares

Ontology: Neuromuscular Depolarizing Agents (C0027867)

Definition (MSH) Drugs that interrupt transmission at the skeletal neuromuscular junction by causing sustained depolarization of the motor end plate. These agents are primarily used as adjuvants in surgical anesthesia to cause skeletal muscle relaxation.
Definition (CSP) drugs that interrupt transmission at the skeletal neuromuscular junction by causing sustained depolarization of the motor end plate; primarily used as adjuvants in surgical anesthesia to cause skeletal muscle relaxation.
Concepts Pharmacologic Substance (T121)
MSH D009467
SnomedCT 22587006, 373250005
English Agents, Neuromuscular Depolarizing, Depolarizing Agents, Neuromuscular, Depolarizing Muscle Relaxants, Muscle Relaxants, Depolarizing, Neuromuscular Depolarizing Agents, Relaxants, Depolarizing Muscle, depolarizing neuromuscular blocking agent, Blockers, Depolarizing, Depolarizing Blockers, neuromuscular depolarizing agents, depolarizing muscle relaxants, agents depolarizing, depolarising muscle relaxants, Neuromuscular depolarizing agents, Depolarising muscle relaxant, Depolarizing muscle relaxant, Depolarising agent, Depolarizing agent (product), Depolarizing agent (substance), Depolarizing agent, Depolarizing agent, NOS
French Curarisants dépolarisants, Myorelaxants dépolarisants, Inhibiteurs neuromusculaires dépolarisants, Curarisants acétylcholino-mimétiques, Curarisants acétylcholinomimétiques
Swedish Neuromuskulära depolariserande medel
Czech nervosvalové látky depolarizující, depolarizující myorelaxancia
Finnish Hermo-lihasliitosta depolarisoivat lääkkeet
Russian LEPTOKURARE, NERVNO-MYSHECHNYE DEPOLIARIZUIUSHCHIE SREDSTVA, KURAREPODOBNYE SREDSTVA DEPOLIARIZUIUSHCHIE, DEPOLIARIZUIUSHCHIE MIORELAKSANTY, MIORELAKSANTY DEPOLIARIZUIUSHCHIE, ДЕПОЛЯРИЗУЮЩИЕ МИОРЕЛАКСАНТЫ, КУРАРЕПОДОБНЫЕ СРЕДСТВА ДЕПОЛЯРИЗУЮЩИЕ, ЛЕПТОКУРАРЕ, МИОРЕЛАКСАНТЫ ДЕПОЛЯРИЗУЮЩИЕ, НЕРВНО-МЫШЕЧНЫЕ ДЕПОЛЯРИЗУЮЩИЕ СРЕДСТВА
Italian Farmaci depolarizzanti, Bloccanti depolarizzanti, Rilassanti muscolari depolarizzanti, Sostanze depolarizzanti del sistema neuromuscolare
Polish Leptokurary, Czynniki depolaryzujące połączenia nerwowo-mięśniowe
Japanese 神経筋脱分極剤, 神経筋接合部脱分極物質, 神経筋脱分極薬, 脱分極性筋弛緩薬, 脱分極性遮断薬
Portuguese Fármacos Neuromusculares Despolarizantes, Despolarizantes Neuromusculares, Relaxantes Musculares Despolarizantes
Spanish Fármacos Neuromusculares Despolarizantes, Agentes Neuromusculares Despolarizantes, Agentes Despolarizantes Neuromusculares, agente despolarizante (producto), agente despolarizante (sustancia), agente despolarizante, Relajantes Musculares Despolarizantes
German Depolarisierende Muskelrelaxantien, Muskelrelaxantien, depolarisierende, Neuromuskulär depolarisierende Wirkstoffe

Ontology: Neuromuscular blocking therapy (C1112352)

Concepts Therapeutic or Preventive Procedure (T061)
Italian Terapia di blocco neuromuscolare, Curarizzazione
Dutch curarisatie, neuromusculaire blokkeringstherapie
French Curarisation, Traitement par blocage neuromusculaire
German Curarisierung, Kurarisierung, Behandlung durch neuromuskulaere Blockade
Portuguese Curarização, Terapia de bloqueio neuromuscular
Spanish Curarización, Terapia de bloqueo neuromuscular
Japanese 神経筋ブロック療法, シンケイキンブロックリョウホウ, クラーレカ, クラーレ化
English Curarisation, Curarization, Neuromuscular blocking therapy
Czech Podání látek blokujících nervosvalový přenos, Kurarizace
Hungarian Kurarizáció, Neuromuscularis blokkoló kezelés, Curarisatio