Drug dose calculation questions - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 12-11-2011
USMLE Forums Guru
 
Steps History: ---
Posts: 332
Threads: 48
Thanked 170 Times in 109 Posts
Drug Drug dose calculation questions

Normally, acetaminophen has a Vd =70L and CI = 350 mUmin. If acetaminophen was administered to a patient with 50% renal function, what parameter would differ from normal?

A. Loading dose would be higher
B. Maintenance dose would be higher
C. t 1/2 would be shorter
D. Vd would be 35L
E. Cl would be 700 mUmin


At 6 h after IV administration of bolus dose, the plasma level of a drug is 5 mgli. If the Vd = 10 L and the elimination half-life == 3 h, what was the dose administered?

A. l00 mg
B. 150 mg
C. 180 mg
D. 200 mg
E. 540 mg

Pls note that these two questions are not related.

Last edited by usluipek; 12-11-2011 at 07:36 PM.
Reply With Quote Quick reply to this message



  #2  
Old 12-12-2011
shyangel18's Avatar
USMLE Forums Guru
 
Steps History: 1 + CS
Posts: 388
Threads: 48
Thanked 237 Times in 128 Posts
Reputation: 247
Send a message via MSN to shyangel18
Default

Hmm. The loading dose doesnt change. MD decreases. Vd shud not change. N same goes for half life. So only option left z E. Tho i still dpnt understand how xan xlearance increase??!
__________________
Ppl come here to study n ponder
I am here to Excell like Thunder!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message
The above post was thanked by:
usluipek (12-12-2011)
  #3  
Old 12-12-2011
shyangel18's Avatar
USMLE Forums Guru
 
Steps History: 1 + CS
Posts: 388
Threads: 48
Thanked 237 Times in 128 Posts
Reputation: 247
Send a message via MSN to shyangel18
Default

2nd question. I suck at maths n fprmulas. But acc to Vd= dose / conc in plasma.. Anser shud b 10 * 5= 50! Which z not evn on the option!! So i dunno. But temme the answerzz!!
__________________
Ppl come here to study n ponder
I am here to Excell like Thunder!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message
 
  #4  
Old 12-12-2011
USMLE Forums Scout
 
Steps History: Not yet
Posts: 50
Threads: 7
Thanked 16 Times in 12 Posts
Reputation: 26
Default

1) I didnt find any correct answer..

2) 150 mg (b)
Since passed 2 half lives, it was 15 mg concentration when the drug was administred, 10 = x/15 = 150 mg... am I right?
Reply With Quote Quick reply to this message
The above post was thanked by:
usluipek (12-12-2011)
  #5  
Old 12-12-2011
USMLE Forums Guru
 
Steps History: ---
Posts: 332
Threads: 48
Thanked 170 Times in 109 Posts
Default

Hi, jriella,

For the first question, the book's answer is B, but I do not quite understand why it is B, because the maintenance dose should be lower.

For the second question, can you tell me how you get to this conclusion?
Reply With Quote Quick reply to this message
  #6  
Old 12-12-2011
USMLE Forums Scout
 
Steps History: Not yet
Posts: 50
Threads: 7
Thanked 16 Times in 12 Posts
Reputation: 26
Default

Probably, there's a mistake with the alternatives..

Thinking again, I dont think that I did it right... dont know how to answer ;(
Reply With Quote Quick reply to this message
  #7  
Old 12-12-2011
USMLE Forums Guru
 
Steps History: ---
Posts: 332
Threads: 48
Thanked 170 Times in 109 Posts
Default

Quote:
Originally Posted by jriella View Post
Probably, there's a mistake with the alternatives..

Thinking again, I dont think that I did it right... dont know how to answer ;(
Your answer is right on the second one, but I just would like to know how you got the answer.
Reply With Quote Quick reply to this message
  #8  
Old 12-12-2011
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 791
Threads: 76
Thanked 673 Times in 317 Posts
Reputation: 691
Thumbs Up

Quote:
Originally Posted by jriella View Post
1) I didnt find any correct answer..

2) 150 mg (b)
Since passed 2 half lives, it was 15 mg concentration when the drug was administred, 10 = x/15 = 150 mg... am I right?
for 2nd question, after 6 hrs of administration its 5 mg. after 3 hrs it should be 10mg and at the time of administration it should be 20mg. hence ans s 200mg dose.
Reply With Quote Quick reply to this message
  #9  
Old 12-13-2011
dr.muhamad's Avatar
USMLE Forums Guru
 
Steps History: 1 + CS
Posts: 300
Threads: 22
Thanked 97 Times in 62 Posts
Reputation: 107
Default

E and D

-when ur kidney doesnt work then the clearance decrease
-tow halflives back from 5 is 20
Reply With Quote Quick reply to this message



Reply

Tags
Pharmacology-, Step-1-Questions

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
drug ad & abstract questions youssef2310 USMLE Step 2 CK Forum 4 09-03-2011 10:50 AM
Beware of the Drug ad and abstract questions!! theunique USMLE Step 2 CK Forum 0 06-30-2011 10:47 AM
Genetic Calculation Questions sana akbar USMLE Step 1 Forum 1 05-02-2011 03:57 PM
is there physiology calculation questions in usmle MedicalDR14 USMLE Step 1 Forum 1 11-09-2010 10:44 AM
Calculation questions in Step 1 lemontea88 USMLE Step 1 Forum 3 01-21-2010 02:00 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)