THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
JANUARY,  1890. 
INCOMPATIBILITY  IN  PRESCRIPTIONS. 
By  Joseph  W.  England,  Ph.G. 
Read  at  the  Pharmaceutical  Meeting,  December  17th. 
Incompatibility  in  a  prescription  has  been  defined  as  that  condition 
in  which  there  exists  either  "  a  chemical  decomposition,  a  pharmaceu- 
tical dissociation,  or  a  therapeutical  opposition "  of  its  constituents. 
The  term  is  thus  susceptible  of  three  meanings.  A  prescription  is 
chemically  incompatible,  where  chemical  change  results.  It  is  phar- 
maceutically  incompatible  where  there  is  violation  of  correct  pharma- 
ceutical procedure,  and  there  is  therapeutical  incompatibility  where 
there  is  antagonism  in  physiological  action.  Now,  accepting  these 
definitions,  a  prescription  may  be  chemically  incompatible  and  yet  be 
just  what  the  physician  wants.  It  may  be  pharmaceutical ly  incom- 
patible and  yet  be  desirable  for  the  same  reason.  But  it  is  never 
compatible  where  there  is  a  change  of  chemical  composition  and  phar- 
maceutical character  resulting  in  the  formation  of  new  products 
having  totally  different  therapeutical  effects  than  those  obviously 
intended.  And  this  view — the  intended  therapeutical  action  of  the 
prescription — is  the  "  keystone  of  the  arch  "  and  the  best  rule  for  the 
pharmacist  to  follow. 
Every  new  prescription  is  largely  a  law  unto  itself  until  tried. 
Expertness  in  pharmaceutical  manipulation,  of  which  prescription 
work  is  the  highest  type,  is  a  matter  of  individual  ability  which  can 
be  acquired,  only  in  the  largest  and  best  measure,  by  personal  experi- 
ence. The  subject  of  incompatibles  is  not  a  formidable  one,  if  there 
primarily  exists  a  clear  knowledge  of  the  chemical  or  pharmaceutical 
properties  of  the  substances  used,  so  that  any  deviation  from  the  right 
standard  may  be  detected,  but  here  is  the  puzzling  question :  How  are 
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