function set_drug(drug_num, gmax, xloc)

global handles vars

drughandle = handles.(['drug' int2str(drug_num)]);

if (gmax==0)
  vars.(['gmult' int2str(drug_num)]) = 1;
  set(drughandle.helpt,'visible','on')
  set(drughandle.cursor,'visible','off')
else
  vars.(['gmult' int2str(drug_num)]) = (100-gmax)/100;
  set(drughandle.helpt,'visible','off')
  set(drughandle.cursor,'XData',[xloc xloc],'visible','on')
  if (xloc == drughandle.xmin | abs(xloc-drughandle.xmax) < 12)
    set(drughandle.cursor,'LineStyle','-')
  else
    set(drughandle.cursor,'LineStyle',':')
  end
end