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  #1  
Old 03-27-2013
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Drug Time to reach Drug Steady State

A constant infusion of drug Y is begun. Drug Y has a Volume of Distribution of 5L, and a clearance of 0.05L/h.

Aproximately how long would it take drug Y to reach steady state?

a. 70
b. 100
c. 112
d. 280
e. 400

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  #2  
Old 03-27-2013
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well,clinical steady state is 4xt1/2
t1/2=0.7xVd/CL
0.7x5=3.5
3.5/0.05=70
70x4=280
answer is D
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Old 03-27-2013
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Quote:
Originally Posted by medpack87 View Post
A constant infusion of drug Y is begun. Drug Y has a Volume of Distribution of 5L, and a clearance of 0.05L/h.

Aproximately how long would it take drug Y to reach steady state?

a. 70
b. 100
c. 112
d. 280
e. 400

t1/2 = 0.7 X Vd / Cl

= 0.7 X 5 / 0.05

= 70.

Answer is A.
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  #4  
Old 03-27-2013
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You forgot it takes 4 t1/2 to get to steady state, Dr. Ali.
Answer is D. 4x70=280



Quote:
Originally Posted by Doctor Ali View Post
t1/2 = 0.7 X Vd / Cl

= 0.7 X 5 / 0.05

= 70.

Answer is A.
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Old 03-28-2013
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@q to all members
where to study pharmacokinetics n dynamics from?
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Old 03-28-2013
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Quote:
Originally Posted by neesh View Post
@q to all members
where to study pharmacokinetics n dynamics from?
kaplan+fa+uw
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  #7  
Old 03-28-2013
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Truth is I got this question word to word including the numbers from the qbank. I picked 70 hrs X 4 = 280 hrs, and I got wrong. The correct answer was 70 hrs alone. I re-read the question and from there I came to know that all they wanted was half life alone; which in this case is 70 hours.
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Old 03-28-2013
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here its asked about steady state , so i think 280 is the ans..
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Old 03-29-2013
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Default corect answer is (D):

A constant infusion of drug Y is begun. Drug Y has a Volume of Distribution of 5L, and a clearance of 0.05L/h.

Aproximately how long would it take drug Y to reach steady state?

d. 280


t 1/2 = 0.7 x Vd / CL

t 1/2 = 0.7 x 5 / 0.05

t 1/2=3.5 / 0.05

t 1/2 = 70

clinical steady state = 4-5 x t 1/2

so

clinical steady state = 4 X 70 = 280
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Old 03-31-2013
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That question which I posted is a question from the Qmax question bank from FirstAid. The answer they give in their explanation is 70.

But I am also confused about this question, so I reported it, because it seems to me that they ask for steady state, and you need to multiply 70 x 4 to get 280 as most of you answered.

Also, in the explanation that comes with the question, they start by writing "First you need to calculate for half time", as if a second calculation would be needed to get to the answer, so even the explanation seems incomplete.

It is also known that FirstAid has some kinks, im 2 months away from the exam and im pretty sure the answer is 280, I hope I get a response from the FirstAid team.

Thanks for your feedback guys.
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