Question Set #3: NMJ blockers

Primary uses of neuromuscular-blocking drugs:
1. adult respiratory distress syndrome
2. skeletal muscle relaxation facilitating tracheal intubation
3. skeletal muscle relaxation to improve intraoperative surgical conditions
4. B & C
5. A, B & C
Characteristic(s) of neuromuscular-blocking drugs:
1. CNS depression
2. analgesia
3. both
4. neither
Neuromuscular-blocking drugs --dose guidelines:
1. facilitation tracheal intubation: 2x ED95 dose of nondepolarizing agent
2. optimal intraoperative condition:95%suppression of single twitch response
3. both
4. neither
Succinylcholine (Anectine) pharmacology:
1. rapid onset; long duration of action
2. mechanism for neuromuscular-blocking action: interacts with muscarinic, cholinergic receptors.
3. causes postsynaptic membrane depolarization
4. quality above
Phase I blockade:
1. desensitization blockade
2. depolarization blockade
3. both
4. neither
Electrolyte effect of prolonged phase I blockade
1. reduction in serum potassium
2. increase in serum potassium
Concerning phase I & phase II neuromuscular-blockade:
1. edrophonium (Tensilon) would be expected to antagonize mainly phase I blockade
2. edrophonium (Tensilon) would be expected to antagonize phase II blockade
Influencing time course of succinylcholine (Anectine) duration of action:
1. liver disease
2. presence of neostigmine (Prostigmin)
3. both
4. neither
Prolongs succinylcholine (Anectine) action due to effects on pseudocholinesterase:metoclopramide (Reglan) (10 mg IV):
1. true
2. false
Resistance to succinylcholine (Anectine):
1. obesity
2. genetic factors (increased plasma cholinesterase activity)
3. myasthenia gravis
4. B & C
5. A, B & C
Consequence of normal succinylcholine (Anectine) dosage in a patient with atypical pseudocholinesterase
1. reduced duration of neuromuscular blockade (< one-minute)
2. increased duration of neuromuscular-blockade (to 30 minutes)
3. absence of neuromuscular-blockade
4. increased duration of neuromuscular-blockade (1-3 hours)
Normal dibucaine (Nupercainal, generic) number but altered succinylcholine (Anectine) duration:
1. liver disease
2. presence of anticholinesterases
3. both
4. neither
Moderately prolonged succinylcholine (Anectine) duration of action (30 minutes):
1. homozygous atypical plasma cholinesterase
2. heterozygous atypical plasma cholinesterase
Major side effects associated with succinylcholine (Anectine):
1. cardiac arrhythmias
2. increased intracranial pressure (ICP)
3. increased intragastric pressure
4. hyperkalemia
5. all of the above
Most common cardiac arrhythmias associated with succinylcholine (Anectine):
1. ventricular tachycardia
2. paroxysmal atrial tachycardia
3. Torsades de Pointes
4. sinus bradycardia
Hyperkalemia following succinylcholine (Anectine) -- risk factors
1. clinically unrecognized muscular dystrophy
2. severe skeletal muscle trauma
3. skeletal muscle atrophy (following denervation)
4. unhealed third degree burns
5. all the above
Male children with undiagnosed myopathy, exposed to succinylcholine (Anectine):
1. hyperkalemia
2. rhabdomyolysis
3. cardiac arrest
4. A & C
5. A, B & C
More common muscular dystrophy:
1. Duchenne's muscular dystrophy
2. Becker muscular dystrophy
3. equally probable
To guard against serious adverse effects associated with succinylcholine (Anectine) use in pediatric patients (who may have undiagnosed myopathy)
1. reduce succinylcholine (Anectine) dosage
2. substitute a nondepolarizing neuromuscular-blocking agent for succinylcholine (Anectine)
Most common locations for postoperative succinylcholine (Anectine) myalgia:
1. neck
2. back
3. abdominal muscles
4. B & C
5. A, B & C