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#1




elimination half life of the drug:
10 volunteers in a drug study are administered I/V 500mg of an drug. in a 24 hrs period blood levels are measured.mean data shown belown:
TIME (hr):012369121824 plasma level2423222118151260 (mg/ L) from these data elimination of the drug is which of the folowing?? a') 1hr b) 6hrs c) 12hrs d) 24hrs e) has no fixed value
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#2




0, 1, 2, 3..
24, 23, 22... looks like zero order kinetics here. and clearance is constant no matter what. so is it 24 hours? i may have to rethink this one. D? what am i talking about!!! in Zero order, Clearance is NOT constant. this has to be a 1st order, give me a little more time on this. Last edited by ReggieMiller; 03302013 at 05:00 AM. 
#3




i think 1hour is the ans..
constant amout 1mg/L is eliminated per hour 
#4




I don't know why, but for me, units are important here. what are the units for the answer choices?
it its asking for clearance, should it be in mg/min? but its asking for elimination, so does that mean how long it takes the drug to be completely eliminated? because if that's the case, then it takes 24 hours for the levels to go from 24mg/L to 0mg/L (so regardless of zero or first order kinetics, the elimination of the drug occurs over a period of 24 hours. i'm just confused by the units, because its in only TIME, i feel that its not asking for a rate. 
#5




do you have the correct answer for this question?
i think i'm going to spend the rest of this day figuring out the first part of pharmacology, and then doing all the ANS! want to finally get the concepts down, and get this out of the way11 
#6




corect answer is E)
Quote:
i marked it because i have not seen any constant amount has been eliminated, initialy i found constant amount eliminated after that i didnt found any constant amount elimination and nor it has fixed half life.so how can you say that it is zero order kinetic. CORECT ANSWER IS E) Explanation: the question is asking for the half life of a given drug. half life is defined as time required to decrease the remaining portion of drug in the body by 1/2 and remains constant irrespective of the Cp. in this question the drug concntration decrease by 1mg/L/hour. the initial conc: is 24mg/L at time zero. 12hrs later the drug conc: dec: by 50% and is 12mg/L. Based on definition of half life,drug conc: should b decrease by anothr 50% 12hrs later. 12hrs later or time 24hrs however the concentration is 0. the elimination half life of the investigational drug therefore has no true fixed value. kaplan asesment question.
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#7




Quote:

#8




Quote:
i understand that it decreases by 1mg/L/hr. so far, that makes sense. but where is the question asking for the half life? zero order does not even have half lifes, i understand that. but i don't see anywhere where we are asked to find the half life. doesn't sound like a fair question to me. 
#9




sorry dear, i dont know whether this question is good or not, i shared here because it was diferent from others questions.
this question is from kaplan asesment test.
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#10




metric conversion of grams,miligrams,micrograms,millilietrs and liters
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#11




would you mind copy/pasting the complete question stem? i just don't see how they assuemd we'd have to calculate the half life.

#12




whatever i have posted that is the complete question and explanation of the answer.
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