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submitted by wired-in(48),

Maintenance dose formula is (CssCltau)/F where Css is steady-state target plasma conc. of drug, Cl is clearance, tau is dosage interval & F is bioavailability.

Neither dosage interval nor bioavailability is given, so ignoring those & plugging in the numbers (careful to convert units to mg/kg/day): (12 ug/mL * 1 mg/1000 ug) * (0.09 L/hr/kg * 1000 mL/1 L * 24 hr/1 day) = 25.92 mg/kg/day

...which isn't any of the answer choices listed. They must have rounded 0.09 L/hr/kg to 0.1 L/hr/kg, and doing so gives exactly 28.8 mg/kg/day (choice C)

lispectedwumbologist  That's so infuriating I stared at this question for 20 minutes thinking I did something wrong +41  
hyoid  ^^^^^ +5  
seagull  lol..my math never worked either. I also just chose the closest number. also, screw this question author for doing that. +5  
praderwilli  Big mad +4  
ht3  this is why you never waste 7 minutes on a question.... because of shit like this +8  
yotsubato  Why the FUCK did they not just give us a clearance of 0.1 if they're going to fuckin round it anyways... +12  
bigjimbo  JOKES +  
cr  in ur maths, why did u put 24h/1day and not 1day/24h? if the given Cl was 0.09L/hr/kg. I know it just is a math question, but i´d appreciate if someone could explain it. +  
d_holles  LMAO games NBME plays +1  
hyperfukus  magic math!!!!! how TF r we supposed to know when they round and when they don't like wtf im so pissed someone please tell me step isn't like this...with such precise decimal answers and a calculator fxn you would assume they wanted an actual answer! +1  
jean_young2019  OMG, I've got the 25.92 mg/kg/day, which isn't any of the answer choices listed. So I chose the D 51.8, because 51.8 is double of 25.9......I thought I must have make a mistake during the calculation ...... +4  
atbangura  They purposely did that so if you made a mistake with your conversion like I did, you might end up with 2.5 which was one of the answer choices. SMH +1  
titanesxvi  I did well, but I thought that my mistake was something to do with the conversion and end up choosing 2.5 because it is similar to 25.92 +1  
makinallkindzofgainz  The fact that we pay these people 60 dollars a pop for poorly formatted and written exams boggles my mind, and yet here I am, about to buy Form 24 +5  
qball  Me after plugging in the right numbers and not rounding down : https://i.kym-cdn.com/entries/icons/original/000/028/539/DyqSKoaX4AATc2G.jpg +1  
frustratedllama  Not only do you feel like you're doing sth wrong but then that feeling stays for other questions. sucks so baad +  
fexx  'here.. take 50mg of vyvanse.. I just rounded it up from 30.. dw you'll be fine' (totally doing this with my patients 8-)) +1  


submitted by seagull(840),

out of curiosity, how may people knew this? (dont be shy to say you did or didnt?)

My poverty education didn't ingrain this in me.

johnthurtjr  I did not +1  
nlkrueger  i did not lol +  
ht3  you're definitely not alone lol +  
yotsubato  no idea +  
yotsubato  And its not in FA, so fuck it IMO +1  
niboonsh  i didnt +  
imnotarobotbut  Nope +  
epr94  did not +  
link981  I guessed it because the names sounded similar :D +10  
d_holles  i did not +  
yb_26  I also guessed because both words start with "glu"))) +14  
impostersyndromel1000  same as person above me. also bc arginine carbamoyl phosphate and nag are all related through urea cycle. +  
jaxx  Not a clue. This was so random. +  
wolvarien  I did not +  
ls3076  no way +  
hyperfukus  no clue +  
mkreamy  this made me feel a lot better. also, no fucking clue +1  
amirmullick3  My immediate thought after reading this was "why would i know this and how does this make me a better doctor?" +5  
mrglass  Generally speaking Glutamine is often used to aminate things. Think brain nitrogen metabolism. You know that F-6-P isn't an amine, and that Glucosamine is, so Glutamine isn't an unrealistic guess. +2  
djtallahassee  yea, I mature 30k anki cards to see this bs +3  
taediggity  I literally shouted wtf in quiet library at this question. +1  
bend_nbme_over  Lol def didn't know it. Looks like I'm not going to be a competent doctor because I don't know the hexosamine pathway lol +1  
drschmoctor  Is it biochemistry? Then I do not know it. +2  
snoochi95  hell no brother +  
roro17  I didn’t +  
bodanese  I did not +  
hatethisshit  nope +  
jesusisking  I Ctrl+F'd glucosamine in FA and it's not even there lol +  
batmane  i definitely guessed, for some reason got it down to arginine and glutamine +1  
waterloo  Nope. +  
monique  I did not +  
issamd1221  didnt +  
baja_blast  Narrowed it down to Arginine and Glutamine figuring the Nitrogen would have to come from one of these two but of course I picked the wrong one. Classic. +  
amy  +1 no idea! +  


submitted by hungrybox(579),

Long answer ahead, but bear with me.

HINT: v looks kind of like y, whereas k looks more like x.

y-intercept = 1/Vmax

  • Vmax is the upper limit on how fast a reaction is catalyzed by enzymes.

x-intercept = 1/Km

  • Km is a ranking of how good an enzyme is at binding its substrate. An enzyme with a ranking of 1 is better at binding its substrate than an enzyme with a ranking of 5. (Lower Km = better enzyme)

Note that Vmax, as a measure of performance, can be altered through many things. Meanwhile, Km is a set characteristic of the enzyme, and cannot be altered.

In this example, the enzyme performance (Vmax) is increased by increasing the vitamin cofactor so that it reaches a "normal" activity. However, the enzyme is still inherently shitty due to a congenital defect, so the Km stays the same.

mnemonia  Awesome. +  
ht3  wait line B shows the vmax doesn't change and that the km is getting larger (enzyme is still shitty so larger km) so -1/km would be a smaller number and would approach 0 +1  
lamhtu  You say Km cannot be altered and its staying the same, but the answer of the graph demonstrates a higher Km value. Needing "higher concentrations" of the B6 for enzyme activity is another way of saying Km is higher since more is required for 1/2 vmax activity +3  
sbryant6  Yeah this explanation is wrong. +  


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