drug pre post
   A  11    6
   A   6    4
   D   6    0
   D   8    4
   F  16   13
   F  16   12
   A   8    0
   A  10   13
   D   6    2
   D  19   14
   F  13   10
   F  12    5
   A   5    2
   A   6    1
   D   7    3
   D   8    9
   F  11   18
   F  12   16
   A  14    8
   A  11    8
   D   8    1
   D   5    1
   F   9    5
   F   7    1
   A  19   11
   A   3    0
   D  18   18
   D  15    9
   F  21   23
   F  12   20