Dapsone Related Methemoglobinemia - 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 09-30-2012
beka-CTS's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 763
Threads: 77
Thanked 1,369 Times in 349 Posts
Reputation: 1379
Drug Dapsone Related Methemoglobinemia

Physician decides to begin preventive medication with his HIV positive patient against Pneumocytis Pneumonia. He prescribes trimethoprim with sulfamethoxazole. But after several days it becomes clear that patient can't tolerate with them. So he is switched to Dapsone, medication used in patients who can't tolerate TMP-SMX. few hours later patient develops shortness of breath, cyanosis, mental status changes (~50%), headache, fatigue. Diagnosis of drug induced methemoglobinemia is presumed. which of the following drug could lower the risk of dapsone related methemoglobinemia:

a) Rifampin
b) Warfarin
c) Cimetidine
d) Phenoxybenzamine
e) phenylephrine
__________________
Step 1 - 244 [✔] Step 2 CK - 246 [✔] Step 2 CS [✔] Step 3 - 228 [✔] Match [EMORY SOM] YOG: 2013, 4 Months of USCE University Hospital
Reply With Quote Quick reply to this message



  #2  
Old 09-30-2012
sruthi's Avatar
USMLE Forums Addict
 
Steps History: Not yet
Posts: 109
Threads: 24
Thanked 19 Times in 11 Posts
Reputation: 29
Default

dono for sure..bt im guessing rifampin..cz its an enzyme inducer n induces d metabolism of dapsone, reduces its levels n thus lowers d risk of adverse effects...
Reply With Quote Quick reply to this message
  #3  
Old 09-30-2012
venky2600's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,186
Threads: 119
Thanked 821 Times in 434 Posts
Reputation: 831
Send a message via Yahoo to venky2600
Post

also guessing as a) rifampin
Reply With Quote Quick reply to this message
 
  #4  
Old 09-30-2012
rupesh's Avatar
USMLE Forums Guru
 
Steps History: 1 + CS
Posts: 386
Threads: 71
Thanked 193 Times in 109 Posts
Reputation: 203
Send a message via AIM to rupesh
Default

rifampin an enzyme inducer but why to use .....but instead dapsone has been removed and Pentamidine would have been added
Reply With Quote Quick reply to this message
  #5  
Old 09-30-2012
tai35's Avatar
USMLE Forums Addict
 
Steps History: Not yet
Posts: 133
Threads: 25
Thanked 25 Times in 21 Posts
Reputation: 35
Default ?

Some one please post the answer
Thanks
Reply With Quote Quick reply to this message
  #6  
Old 09-30-2012
beka-CTS's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 763
Threads: 77
Thanked 1,369 Times in 349 Posts
Reputation: 1379
I agree

Answer is Cimetidine. Dapsone is metabolized to an oxidizing hydroxylamine compound by cytochrome P-450 3A4. If diagnosed early, dapsone-induced methemoglobinemia can be treated with a potent inhibitor of the 3A4 isoenzyme, such as cimetidine (Drug information on cimetidine), which can inhibit the formation of the hydroxylamine metabolite.
DIT mentioned it very briefly and i decided to share.
See these articles for more accurate information.


http://www.consultantlive.com/displa...le/10162/44514

http://www.ncbi.nlm.nih.gov/pubmed/1352810
__________________
Step 1 - 244 [✔] Step 2 CK - 246 [✔] Step 2 CS [✔] Step 3 - 228 [✔] Match [EMORY SOM] YOG: 2013, 4 Months of USCE University Hospital
Reply With Quote Quick reply to this message
The above post was thanked by:
dockhi (10-01-2012), Janakpriya (10-01-2012), Linc (11-02-2015), nishaa (09-30-2012), Noa2013 (05-17-2015), sruthi (10-02-2012), venky2600 (09-30-2012)



Reply

Tags
Pharmacology-

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
query related to PCOS tyagee USMLE Step 2 CK Forum 5 06-29-2012 10:00 AM
DM drug related question mle2resident USMLE Step 1 Forum 10 06-26-2011 07:49 PM
dapsone, uncommon but important drug in USMLE atr88 USMLE Step 2 CK Bits & Pieces 1 01-24-2011 12:01 PM
HCC related with which Hep virus??? doctorF USMLE Step 1 Forum 4 04-27-2010 10:05 PM
Autonomy related questions DrSeddik USMLE Step 1 Forum 5 01-14-2010 07:51 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)