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#1
03-30-2013
 USMLE Forums Veteran Steps History: 1 + CS Posts: 209 Threads: 18 Thanked 112 Times in 75 Posts Reputation: 122
Half Life of the Drug?

In a healthy person a new antimicrobial agent studied under the clinical phase 1 trial , Vd is about 30 L and CL is 2 L/hr. the t 1/2 life of the drug in this subject is aproximately which of the folowing??

a) 0.05 hrs
b) 10hrs
c) 42hrs
d) 21 hrs
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 The above post was thanked by: docsdr (03-30-2013)

#2
03-30-2013
 USMLE Forums Scout Steps History: Not yet Posts: 42 Threads: 10 Thanked 61 Times in 22 Posts Reputation: 71
Half Life is K x Vd/Cl

B

T1/2 = K x Vd/Cl
0.7 x 30/2
10.5 ~ 11.
 The above post was thanked by: neha_subh (03-30-2013)
#3
03-30-2013
 USMLE Forums Veteran Steps History: 1 + CS Posts: 209 Threads: 18 Thanked 112 Times in 75 Posts Reputation: 122

Quote:
 Originally Posted by neha_subh In a healthy person a new antimicrobial agent studied under the clinical phase 1 trial , Vd is about 30 L and CL is 2 L/hr. the t 1/2 life of the drug in this subject is aproximately which of the folowing?? a) 0.05 hrs b) 10hrs c) 42hrs d) 21 hrs
t 1/2 = 0.7 x vd / CL

t 1/2 = 0.7 x 30 / 2

t 1/2 = 10.5 hrs or 10hrs (b) corect answer
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#4
03-30-2013
 USMLE Forums Veteran Steps History: Step 1 Only Posts: 283 Threads: 35 Thanked 206 Times in 115 Posts Reputation: 216

Quote:
 Originally Posted by neha_subh In a healthy person a new antimicrobial agent studied under the clinical phase 1 trial , Vd is about 30 L and CL is 2 L/hr. the t 1/2 life of the drug in this subject is aproximately which of the folowing?? a) 0.05 hrs b) 10hrs c) 42hrs d) 21 hrs

Sorry if I am late. Too busy with DIT and Fridays I don't do a thing. Alright, so here we use:

t1/2 = 0.7 X Vd / Cl

So,

t1/2 = 0.7 X 30L / 2L/hr

t1/2 = 10.5Hr

so my answer would be B ~ 10 hrs.

 Tags Pharmacology-, Step-1-Questions

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