hamza1892

7+ Year Member
Dec 23, 2011
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Sterling heights
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Pharmacy Student
If a patient was given 250mg of gentamicin at 6am and then drew a level at 12pm and it was 12 and then 5pm you check the level again it was 7.. how would you find the half-life of gentamicin???


thank you for your responses in advance
 

sgkman

2+ Year Member
Jul 26, 2015
17
2
Status
Pharmacist
Use C2 = C1 E^-ke*t equation to find Ke and do 0.693/ke to get half life.

In this case:

12=250e^(-ke)(6)

ln(12/250) = -ke * 6

find Ke and plug in half life equation.
 
Jul 26, 2015
1
0
Status
Pharmacy Student
C1 = 12
C2= 7
Time (Difference in time between two levels) = 12pm - 5pm = 5 hrs
7= 12 x e^(-ke(5))= ln (7/12)/-5 = ke
Half life = 0.693/ke
Answer= 6.4 hrs
 
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confettiflyer

Did you just say something?
15+ Year Member
Dec 19, 2004
9,688
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Best Coast
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Pharmacist
at this point I'd eyeball it and say ~6hrs (12->7 is almost 12->6 therefore the half-life is no less than 5hrs and probably 6-7).
 
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