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NBME 20 Answers

nbme20/Block 3/Question#47
A 60-year-old woman has prolonged apnea ...

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 +9  upvote downvote
submitted by xxabi(195),

The duration of action of Succinylcholine is determined by its metabolism by plasma cholinesterase. So if there is abnormal plasma cholinesterase (=psuedocholinesterase), it will lead to delayed metabolism of succinylcholine as well as mivacirum, heroin, and cocaine.

 +4  upvote downvote
submitted by niboonsh(210),

https://www.youtube.com/watch?v=WGWFFN01qkA succinylcholine usually has v fast duration of action bcuz metabolized by plasma pseudocholinesterase. With atypical pseudocholinesterase, decreased metabolism of succinylcholine and thus causes a prolonged duration of action of succinylcholine ----> APNEA

chandlerbas  i love that mosquito and then SLAP +  

 +0  upvote downvote
submitted by thomas(-2),

Not sure about this, but it seems to me that this is referring to "pseudocholinesterase inhibitor deficiency. It's an enzyme defect that is triggered by NMJ blockers - succinylcholine or curare's.


usmleuser007  I believe this question was stating that AchE activity was abnormal = it was not lowering the Ach activity. Which suggests that another ligand like Ach was being used. +  

 +0  upvote downvote
submitted by haozhier(3),

From FA, succinylcholine can be reversed during phase 2 by cholinesterase inhibitor. Can someone explain if succinylcholine is metabolized by cholinesterase, how can we use cholinesterase inhibitors to reverse it?

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