Question on pharmacokinetics

[hamza1892]

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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]

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.

 

[succulents222]

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

 

[confettiflyer]

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).

 

[hamza1892]

Thank you, everyone for your answers! I really appreciate it 🙂