NMBs Flashcards
Rocuronium Class
Steroidal nondepolarizing muscle blocking agent
Rocuronium Clinical Use
Standard and rapid sequence induction, reduce damage to vocal cords
maintenance of neuromuscular blockade
Improve surgical working conditions, immobility
Rocuronium MOA
Competitively blocks nicotinic receptors in the NMJ preventing ACh from binding → channel remains closed and post synaptic membrane remains polarized
Rocuronium Dose
Induction dosing: 0.6 – 1.2 mg/kg
RSI dose: 1.2 mg/kg
Maintenance 1/5th
Rocuronium Pharmacokinetics
Onset = 1 - 3 min
DOA = 30 - 60 min
Metabolism = hepatic and renal
Excretion = Liver 20% and kidney 80%
Rocuronium Contraindications
hypersensitivity - Neuromuscular blocking agents and antibiotics are the most common drugs involved in intraoperative allergic reactions
Depend on hepatic and renal elimination, caution in patients with impaired function
Rocuronium Considerations
- No hypnosis or analgesia
- Quaternary ammonium does NOT cross BBB
- sedated prior to admin and adequate ventilation
- Reverse with sugammadex
- Hepatic and renal system
- The steroidal relaxants rocuronium & vecuronium depend to varying degrees on renal and hepatic elimination
- Hypothermia prolongs duration of action.
- Drug interactions:
- Prolonged by:
- Volatiles
- Hypothermia
- Magnesium
- Lithium
- IV local anesthetic
- Shortened by:
- Long term anti-epileptics, resistant to NMB
- Steroids antagonize NMB
Vecuronium Class
Steroidal nondepolarizing muscle blocking agent
Vecuronium Use
- Standard induction and maintenance of neuromuscular blockade
- Improve surgical working conditions, immobility
Vecuronium MOA
Competitively blocks nicotinic receptors in the NMJ preventing ACh from binding → channel remains closed and post synaptic membrane remains polarized
Vecuronium Dose
Induction = 0.1 mg/kg
Vecuronium Pharmacokinetics
- Onset = 2 - 4 min
- DOA = 30 - 60 min
- Metabolism = hepatic and renal
- Excretion = Liver 50% and kidney 50%
Vecuronium Contraindications
- hypersensitivity - Neuromuscular blocking agents and antibiotics are the most common drugs involved in intraoperative allergic reactions
- Depend on hepatic and renal elimination, caution in patients with impaired function
Vecuronium Considerations
- No hypnosis or analgesia
- Quaternary ammonium does NOT cross BBB
- Must be reconstituted
- Reverse with sugammadex
- Hepatic and renal system
- The steroidal relaxants rocuronium & vecuronium depend to varying degrees on renal and hepatic elimination
- Hypothermia prolongs duration of action
- Drug interactions:
Prolonged by:
- Volatiles
- Hypothermia
- Magnesium
- Lithium
- IV local anesthetic
- Shortened by:
- Long term anti-epileptics, resistant to NMB
- Steroids antagonize NMB
Cisatracurium Class
Benzylisoquinolinium nondepolarizing muscle blocking agent
Cisatracurium Use
- Standard induction and maintenance of neuromuscular blockade
- Improve surgical working conditions, immobility
Cisatracurium MOA
Competitively blocks nicotinic receptors in the NMJ preventing ACh from binding → channel remains closed and post synaptic membrane remains polarized
Cisatracurium Dose
Induction 0.1 mg/kg
Cisatracurium Pharmacokinetcs
- Onset = 2 - 4 min
- DOA = 30 - 60 min
- Metabolism = Hoffman elimination (75%) and nonspecific esterase hydrolysis (25%)
- Laudanosine metabolite (CNS stimulant)
- Excretion = Kidney
Cisatracurium Contraindications
hypersensitivity - Neuromuscular blocking agents and antibiotics are the most common drugs involved in intraoperative allergic reactions
Cisatracurium Considerations
- No hypnosis or analgesia
- Quaternary ammonium does NOT cross BBB
- Hofmann elimination is a temperature- and pH-dependent break- down of the drug molecule.
- CANNOT! reverse with sugammadex
- Best agent for patients with kidney or liver failure
- Hypothermia prolongs duration of action
- Drug interactions:
Prolonged by:
- Volatiles
- Hypothermia
- Magnesium
- Lithium
- IV local anesthetic
- Shortened by:
- Long term anti-epileptics, resistant to NMB
- Steroids antagonize NMB
Succinylcholine Class
Depolarizing muscle blocking agent
Succinylcholine Clinical Use
rapid sequence induction, laryngospasm, ECT
Succinylcholine MOA
Attaches to one or both alpha subunits of the nicotinic acteylcholine receptors and mimics ACh, thus depolarizing the postjunctional membrane
Succinylcholine Dose
- Induction dosing: 1 – 1.5 mg/kg
- IM induction: 4 mg/kg
- Laryngospasm: 20 - 40 mg
Succinylcholine Pharmacokinetics
- Onset = 30 - 60 sec
- DOA 5 - 15 min
- Metabolism = plasma cholinesterases (pseudocholinesterases/butyrocholinesterase) which are made in the liver. Prolonged metabolism with plasma cholinesterase deficiency
- Excretion = kidneys
Succinylcholine Contraindications
- HyperKalemia
- Burn patients with injuries of over 35% total Body surface area (TBSA),third-degree burn
- Severe muscle trauma
- Neurologic injury (e.g., paraplegia, quadriplegia)
- Severe sepsis (e.g., abdominal)
- Muscle wasting, prolonged immobilization, extensive muscle denervation
- Malignant hyperthermia or family history
- Duchenne muscular dystrophy
- Children <8 yo (Should only be used in children under 8 years old only in emergency situations; not for routine intubation)
- Genetic variants of pseudocholinesterase defect (dibucaine test, 80% inhibition is normal)
- Allergy
Succinylcholine Considerations
- Bradycardia due to direct stimulation of muscarinic receptors of the SA node
- F/U w/ atropine
- Risk of hyperkalemia, worse with burn/trauma/head injury patients
- Increases ICP, IOP and gastric pressures
- Fasciculations and post op muscle pain can occur
- Rhadbomyolysis can lead to hyperkalemia and cardiac arrest
- Quaternary ammonium does NOT cross BBB
