NBME 23 Answers : Block 2 : #15 = A child with septicemia has an antibiotic clearance ...

+12 upvote downvote
submitted by wired-in(27),

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 +18

hyoid ^^^^^ +2

seagull lol..my math never worked either. I also just chose the closest number. also, screw this question author for doing that. +2

praderwilli Big mad +4

ht3 this is why you never waste 7 minutes on a question.... because of shit like this +5

yotsubato Why the FUCK did they not just give us a clearance of 0.1 if they're going to fuckin round it anyways... +6

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 +

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! +

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 ...... +

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 +