Neuromuscular Blockers Flashcards
Purpose of NM blockers
Promote muscular relaxation: Surgery (abdominal wall) Mechanical ventilation Endotracheal Scopes
4 Categories of neuromuscular blockers
Cisatracurium
Rapacuronium
Succinylcholine
Tubocurarine
Succinylcholine MOA
Depolarizing
Agonist
NM end plate effect
Cisatricurium, rapacuronium, tubocurarine MOA
Non-Depolarizing, antagonist, competitive
Tubocurarine
Low dose: can be overcome by AchE inhibs: edrophonium, neostigmine
High dose: AchE are less effective
Phases of neuromuscular end plate effects
Phase 1: prolonged depolarization
Phase 2: repolarized but desensitized
Cardiovascular effects of Succinylcholine
Bradycardia (strong agonist at cardiac M2 muscarinic receptors)
Cardiac effects of Rapacuronium
Mild vagolytic, tachycardia
Cardiac effects Tubocurarine
Hypotension, tachycardia
Side effects of Succinylcholine
Hyperkalemia (opening of nicotinic receptors leads to efflux of K)
Malignant hyperthermia (use Dantrolene for rapid cooling)
Increased IOP, intragastric pressure, muscle pain
Contraindicated in CHF, patients taking Digitalis
Tubocurarine selectivity
Non-depolarizing nicotinic receptor antagonist
Tubocurarine side effects
Hypotension
Tachycardia
Rarely used as Tx agent
Due to moderate blockade of nicotinic receptors at the ganglia
Pharmacokinetics of Cisatracurium
Actions terminated by spontaneous degradation
Indications of succinylcholine
To facilitate rapid endotracheal intubation
Indications for Botox
Headaches Upper limb spasiticity Cervical dystonia Tx of strabismus Severe primary axillary sweating (sympathetic cholinergic) Cosmetics
