Hello dear , hi
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I  have evaluated your query thoroughly .
*  It takes  time  for  various period  for different  cases for 
warfarin     reduction  according  to  the  clinician  concern .
*  Guidelines for stomach pain  
-  Additional intake of 
proton pump inhibitor  as  
omeprazole or     
pantoprazole  before meals with sips of water helps a lot .
-  Take warfarin  always  after  meals .
-  Diet should   be  soft , light in nature .
-  Avoid smoking , alcohol , spicy , non veg , hot beverages , junk foods .
-  No  smoking , alcohol if using .
-  Avoid  stress , 
anxiety .
-  Have  regular sound sleep  of  8  hours .
Hope this will help you for sure .
Regards .