290 
Current  Literature. 
Am.  Jour.  Pharm. 
June,  1917. 
when  given  in  any  other  way,  cocaine  being  about  50  times  as  toxic 
as  novocaine.  Feeding  mice  on  sublethal  doses  of  novocaine  for  a 
period  of  weeks  did  not  seem  to  confer  immunity  to  cocaine  when 
the  mice  were  fed  on  cocaine  in  the  same  way. 
The  effects  of  novocaine  on  the  isolated  heart  of  the  frog  re- 
semble the  effects  produced  by  cocaine,  both  substances  causing  a 
decrease  in  rate  of  the  heart  and  a  decrease  in  the  extent  of  systole. 
The  relative  toxicity  on  the  heart  of  the  frog  as  determined  by  per- 
fusion experiments  is  less  for  novocaine  than  for  cocaine.  On 
smooth  muscle,  the  effect  of  novocaine  differs  slightly  from  that  pro- 
duced by  cocaine.  On  the  isolated  ureter  of  the  dog,  the  isolated 
urinary  bladder  and  stomach  of  the  cat,  and  the  isolated  uterus  of 
the  rabbit,  the  effect  of  novocaine  differs  from  that  of  cocaine 
only  in  being  stimulating  to  a  less  degree  when  similar  dilutions  are 
used.  On  the  isolated  intestine  of  the  rabbit,  cocaine  stimulates  in 
dilute  solutions,  and  in  concentrated  solutions  depresses  intestinal 
motility,  whereas  novocaine  depresses  it  in  any  effective  concentra- 
tion. On  the  blood  pressure  and  respiration,  both  cocaine  and  novo- 
caine increase  blood  pressure  and  respiration  in  small  doses  and  de- 
press in  large  doses.  When  given  subdurally,  the  relative  toxicity  of 
cocaine  and  novocaine  is  practically  the  same,  as  shown  by  the  com- 
parative effects  on  the  blood  pressure  and  respiration.  Death  in 
rabbits  after  cocaine  or  novocaine  poisoning  is  usually  respiratory, 
but  with  novocaine  under  certain  conditions,  death  may  be  cardiac. 
1.  Novocaine  is  several  times  less  toxic  for  laboratory  animals 
than  cocaine,  the  relative  toxicity  being  dependent  upon  the  method 
of  administration  as  well  as  upon  the  animal  used  in  making  the 
determination. 
2.  Novocaine  possesses  many  of  the  properties  of  cocaine  as 
shown  by  experiments  on  the  isolated  heart,  on  smooth  muscle,  and 
by  its  effects  on  the  circulation  and  respiration  of  anaesthetized 
animals. 
3.  The  depressing  effect  of  novocaine  on  the  blood  pressure  and 
respiration  of  animals  makes  it  necessary  to  use  caution  in  its  ad- 
ministration in  clinical  cases  in  which  the  blood  pressure  is  low  or 
in  which  the  heart  is  at  fault. 
4.  Great  care  should  be  exercised  in  the  injection  of  novocaine 
subcutaneously,  in  order  to  avoid  its  entrance  into  the  circulation, 
thereby  increasing  its  toxicity. 
5.  Individual  susceptibility  should  always  be  considered  in  the 
administration  of  either  cocaine  or  novocaine. 
