Sat27November0556PM 41

Non-depolarising muscle relaxants:

True / False

Rocuronium is hydrolysed in the plasma and undergoes some degree of liver metabolism Incorrect answer selected

Include the aminosteroids, rocuronium, vecuronium and pancuronium Correct

Hofmann elimination of atracurium is pH and temperature dependent Correct

Are competitive antagonists at the neuromuscular junction Correct

The primary effect is to bind to the a-subunit of the nicotinic receptor on the pre-junctional membrane Correct

Explanation

Non-depolarising muscle relaxants (NDMRs) inhibit the actions of acetylcholine at the neuromuscular junction by binding competitively to the a-subunit of the nicotinic acetylcholine receptor on the post-junctional membrane. They also have effects on prejunctional receptors that serve to modulate acetyl choline release. Blockade of the receptors are thought to be responsible for fade during tetanic stimululi or train of four. They can be classified as aminosteroid compounds that include vecuronium, rocuronium and pancuronium. The benzylquinolinium class include atracurium, mivacurium and tubocurarine.

Atracurium has a unique metabolic pathway and undergoes ester hydrolysis accounting for 60% of its metabolism, and Hofmann elimination, which is temperature and pH dependent. As pH and temperature decrease, Hofmann elimination also decreases and the reverse applies to and increase in temperature and pH.

Rocuronium is mainly excreted unchanged in the bile and to a lesser extent in the urine.

Answer Statistics

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Average score: 80.46%

Times answered: 262