Student or Learner
I have been unlucky this time. The medical prescription/drug prescribed by doctor is not available in the pharmacy. I have to go and buy it from the drugstore.
Which [of the two] is good?
First one, say, "My/this prescription...".
Second one, say, "The drug prescribed by my/the doctor..."
Use "my" if it is yours, "this" or "the" if not.