Combining multiple rows from 2 columns into sorted columns depending on 1st columns value

[Dexamphetamine]

Hi all,
Working on FDA adverse events database and have several Gig of excel files (from ASCII) that I am trying to sort and combine.
Basically Column A has the identifier and Column B the adverse event. Each identifier can have multiple adverse events.
I wish to convert the data such that there is only 1 identifier and each adverse event is listed across the columns.
Attached is a sample from the file that I am working with.
Thanks in advance!