RT Book, Section
A1 Howland, Mary Ann
A2 Hoffman, Robert S.
A2 Howland, Mary Ann
A2 Lewin, Neal A.
A2 Nelson, Lewis S.
A2 Goldfrank, Lewis R.
SR Print(0)
ID 1108421741
T1 Antidotes in Depth
T2 Goldfrank's Toxicologic Emergencies, 10e
YR 2015
FD 2015
PB McGraw-Hill Education
PP New York, NY
SN 9780071801843
LK accesspharmacy.mhmedical.com/content.aspx?aid=1108421741
RD 2024/04/18
AB Physostigmine  is  a  carbamate  that  reversibly  inhibits  cholinesterases  in  the  peripheral  nervous  system  and  central  nervous  system  (CNS).46  The  tertiary  amine  structure  of  physostigmine  permits  CNS  penetration  and  differentiates  it  from  neostigmine  and  pyridostigmine,  which  are  quaternary  amines  that  have  limited  ability  to  enter  the  CNS.  The  inhibition  of  cholinesterases  prevents  the  metabolism  of  acetylcholine,  allowing  acetylcholine  to  accumulate  and  antagonize  the  antimuscarinic  effects  of  xenobiotics  such  as  atropine,  scopolamine,  and  diphenhydramine.54  Although  physostigmine  previously  was  used  as  an  antagonist  to  the  antimuscarinic  effects  of  cyclic  antidepressants  and  phenothiazines,  this  use  is  no  longer  recommended  because  of  a  poor  risk-to-benefit  ratio,  given  the  potential  for  exacerbation  of  life-threatening  cardiotoxicity.  Similarly,  physostigmine  has  a  poor  risk-to-benefit  ratio  in  the  management  of  presumed  γ-hydroxybutyric  acid  (GHB)  toxicity.4,48,55  Atypical  antipsychotics  have  complex  pharmacologic  effects.  Although  some  atypical  antipsychotics,  such  as  olanzapine,  have  significant  antimuscarinic  side  effects,  the  benefit  of  treating  these  anticholinergic  effects  with  physostigmine  must  be  weighed  by  the  potential  risks  of  exacerbating  cardiotoxicity.19,47,53