TY  - CHAP
M1  - Book, Section
TI  - NITRITE, SODIUM, AND AMYL
A1  - Tsutaoka, Ben
A2  - Olson, Kent R.
A2  - Anderson, Ilene B.
A2  - Benowitz, Neal L.
A2  - Blanc, Paul D.
A2  - Clark, Richard F.
A2  - Kearney, Thomas E.
A2  - Kim-Katz, Susan Y.
A2  - Wu, Alan H. B.
PY  - 2018
T2  - Poisoning & Drug Overdose, 7e
AB  - Pharmacology.  Sodium  nitrite  injectable  solution  and  amyl  nitrite  crushable  ampules  for  inhalation  are  components  of  the  cyanide  antidote  package.  The  value  of  nitrites  as  an  antidote  to  cyanide  poisoning  is  twofold:  They  oxidize  hemoglobin  to  methemoglobin,  which  binds  free  cyanide,  and  they  may  enhance  endothelial  cyanide  detoxification  by  producing  vasodilation.  Inhalation  of  an  ampule  of  amyl  nitrite  produces  a  methemoglobin  level  of  about  5%.  Intravenous  administration  of  a  single  300-mg  dose  of  sodium  nitrite  in  adults  is  anticipated  to  produce  a  methemoglobin  level  of  about  15-20%.IndicationsSymptomatic  cyanide  poisoning.  Nitrites  are  not  usually  used  for  empiric  treatment  unless  cyanide  is  suspected  very  strongly,  and  they  are  not  recommended  for  smoke  inhalation  victims.Nitrites  are  possibly  effective  for  hydrogen  sulfide  poisoning  if  given  within  30  minutes  of  exposure.ContraindicationsSignificant  preexisting  methemoglobinemia  (>40%).Severe  hypotension  is  a  relative  contraindication  because  it  may  be  worsened  by  nitrites.Administration  to  patients  with  concurrent  carbon  monoxide  poisoning  is  a  relative  contraindication;  generation  of  methemoglobin  may  further  compromise  oxygen  transport  to  the  tissues.  Hydroxocobalamin  has  supplanted  nitrites  for  smoke  inhalation  victims  (patients  often  have  mixed  carbon  monoxide  and  cyanide  poisoning)  in  countries  where  it  is  available.Adverse  effectsHeadache,  facial  flushing,  dizziness,  nausea,  vomiting,  tachycardia,  and  sweating  may  occur.  These  side  effects  may  be  masked  by  the  symptoms  of  cyanide  poisoning.Rapid  intravenous  administration  may  result  in  hypotension.Excessive  and  potentially  fatal  methemoglobinemia  may  result.Use  in  pregnancy.  No  assigned  FDA  category.  These  agents  may  compromise  blood  flow  and  oxygen  delivery  to  the  fetus  and  may  induce  fetal  methemoglobinemia.  Fetal  hemoglobin  is  more  sensitive  to  the  oxidant  effects  of  nitrites.  However,  this  does  not  preclude  their  acute,  short-term  use  for  a  seriously  symptomatic  patient  (Introduction).Drug  or  laboratory  interactionsHypotension  may  be  exacerbated  by  the  concurrent  presence  of  alcohol  or  other  vasodilators  or  any  antihypertensive  agent.Methylene  blue  should  not  be  administered  to  a  cyanide-poisoned  patient  because  it  may  reverse  nitrite-induced  methemoglobinemia  and  theoretically  result  in  the  release  of  free  cyanide  ions.  However,  it  may  be  considered  when  severe  and  life-threatening  excessive  methemoglobinemia  is  present.Binding  of  methemoglobin  to  cyanide  (cyanomethemoglobin)  may  lower  the  measured  free  methemoglobin  level.Dosage  and  method  of  administrationAmyl  nitrite  crushable  ampules.  Crush  one  to  two  ampules  in  gauze,  cloth,  or  a  sponge  and  place  under  the  nose  of  the  victim,  who  should  inhale  deeply  for  30  seconds.  Rest  for  30  seconds,  then  repeat.  Each  ampule  lasts  about  2–3  minutes.  If  the  victim  is  receiving  respiratory  support,  place  the  ampules  in  the  face  mask  or  port  access  to  the  endotracheal  tube.  Stop  ampule  use  when  administering  intravenous  sodium  nitrite.Sodium  nitrite  parenteralAdults.  Administer  300  mg  of  sodium  nitrite  (10  mL  of  3%  solution)  IV  over  3–5  minutes.Children.  Give  5.8-11.6  mg/kg  to  a  maximum  of  300  mg.  Pediatric  dosing  should  be  based  on  the  hemoglobin  concentration  if  it  is  known  (Table  III–13).  If  anemia  is  suspected  or  hypotension  is  present,  start  with  the  lower  dose,  dilute  in  50–100  mL  of  saline,  and  give  over  at  least  5  minutes.Oxidation  of  hemoglobin  to  methemoglobin  occurs  within  30  minutes.  If  no  response  to  treatment  occurs  within  30  minutes,  an  additional  half-size  dose  of  intravenous  ...
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/19
UR  - accessmedicine.mhmedical.com/content.aspx?aid=1174607506
ER  -