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#1




Calculated the half life for this drug?
A new antiepileptic drug is being studied. The first test subject is determined to have a volume of distribution of 60 L for this drug and a renal clearance of 4 L/hour. What is the approximate half life of this drug in this patient?
A  2 hours B  7.5 hours C  10 hours D  15 hours E  18 hours 
#2




Cl = Vd x 0,67/half life
half life = Vd x 0.67/Cl = 60 x 0.67/4 = 10 hours The answer is : C
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#3




B , 7.5 hrs



#4




answer
Quote:

#5




Quote:
Hey, why do we need to divide the vd by 2? 
#6




C. 10 hours. The initial formula was correct.
T1/2 = 0.7 x Vd/Cl There's no need to divide by 2 ?!? 
#7




First we know that:
k = 0.693 / t 1/2 ==> t 1/2 = 0.693 / k and Clearence = V * k ==> k = Clearence / V then, t 1/2 = ( 0.693 * V ) / Clearence ==> 0.693 * 60 / 4 = 10 aprox. C  10 hours 
The above post was thanked by:  
aktorque (04012011) 
#8




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The above post was thanked by:  
bronchiole (04022011), harlesmd (04012011) 
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Pharmacology, Step1Questions 
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