NBME 20 Answers : Block 3 : #47 = A 60-year-old woman has prolonged apnea following ...

nbme20/Block 3/Question#47

A 60-year-old woman has prolonged apnea following ...

Succinylcholine

+2 upvote downvote
submitted by xxabi(40),

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.

+0 upvote downvote
submitted by thomas(5),

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.

https://en.wikipedia.org/wiki/Pseudocholinesterase_deficiency

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. +

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submitted by niboonsh(0),

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