TY  - CHAP
M1  - Book, Section
TI  - HYDROXOCOBALAMIN
A1  - Meier, Kathryn H.
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.
Y1  - 2018
N1  - 
T2  - Poisoning & Drug Overdose, 7e
AB  - Pharmacology.  Hydroxocobalamin  is  an  analog  of  vitamin  B12  that  is  used  for  the  treatment  of  vitamin  B12  deficiency  syndromes  in  small  doses  and  as  an  antidote  for  human  cyanide  poisoning  in  large  doses.  Hydroxocobalamin  rapidly  exchanges  its  hydroxyl  group  with  free  cyanide  to  produce  nontoxic,  stable  cyanocobalamin.  Since  the  molar  binding  ratio  of  hydroxocobalamin  to  cyanide  is  1:1,  5  g  of  hydroxocobalamin  will  neutralize  97  mg  of  cyanide.  Independent  of  its  cyanide  binding,  hydroxocobalamin  scavenges  nitric  oxide,  a  mediator  of  vasodilation.  When  administered  to  patients  with  cyanide  poisoning,  it  rapidly  improves  the  heart  rate,  systolic  blood  pressure,  and  acidemia.  In  humans,  outcome  is  best  when  hydroxocobalamin  is  administered  before  cardiopulmonary  arrest  occurs.  In  normal  individuals  given  5-  and  10-g  hydroxocobalamin  doses,  the  plasma  half-life  values  for  cobalamin  compounds  average  26  and  31  hours,  respectively.  Oral  absorption  is  poor;  absorption  by  intranasal  route  provides  only  small  nontherapeutic  doses  for  cyanide  poisoning;  large  fluid  volumes  (200  mL)  required  for  each  5  g  dose  preclude  IM  use;  and  intraosseous  administration  is  under  investigation.IndicationsTreatment  of  acute  cyanide  poisoning  or  symptomatic  patients  suspected  to  be  at  high  risk  for  cyanide  poisoning  (eg,  smoke  inhalation  victims?).Prophylaxis  or  treatment  of  cyanide  poisoning  during  nitroprusside  infusion  has  been  proposed.Contraindications.  Use  caution  when  managing  patients  with  known  hypersensitivity  to  hydroxocobalamin  or  cyanocobalamin  and  consider  alternative  treatments.Adverse  effectsAdverse  reactions  in  healthy  volunteers  include  chromaturia  (red-colored  urine)  in  100%,  erythema  in  94-100%,  rash  in  20-44%,  high  blood  pressure  in  18-28%,  nausea  in  6-11%,  headache  in  6-33%,  decreased  lymphocyte  percentage  in  8-17%,  and  infusion  site  reaction  in  6-39%.  Although  red-colored  body  fluids  usually  normalize  within  2–7  days,  erythema  can  last  up  to  2  weeks  and  chromaturia  up  to  35  days.  A  self-limiting  acneiform  rash  may  occur  7–28  days  after  infusion.Allergic  reactions  have  not  been  reported  with  acute  intravenous  therapy  for  cyanide  poisoning.  However,  allergic  reactions  have  been  reported  in  patients  using  chronic  IM  therapy  and  in  healthy  volunteers  unexposed  to  cyanide  who  were  given  IV  hydroxocobalamin  while  participating  in  clinical  safety  trials.Use  in  pregnancy.  FDA  Category  C.  The  acute,  short-term  use  of  hydroxocobalamin  for  a  seriously  symptomatic,  cyanide-poisoned  patient  (Introduction)  is  not  precluded  in  pregnancy  and  is  preferred  over  nitrite  administration.  Cobalamin  compounds  cross  the  placenta  and  have  been  detected  in  human  newborn  urine  samples.Drug  or  laboratory  interactionsColoration  of  bodily  fluids  caused  by  cobalamins  can  interfere  with  colorimetric  laboratory  tests  for  periods  ranging  from  12  to  48  hours  for  blood  and  serum  and  up  to  8  days  for  urine.  Sampling  and  storing  specimens  before  antidote  administration  is  recommended,  if  possible.  Test  interferences  are  variable  depending  on  which  brand  of  analyzer  is  used.  Test  results  that  are  commonly  affected  include:Falsely  decreased  ALT  and  amylase.Falsely  increased  AST,  serum  creatinine,  glucose,  alkaline  phosphatase,  albumin,  total  protein,  bilirubin,  triglycerides,  cholesterol,  hemoglobin,  MCH,  MCHC,  basophils,  and  most  urine  chemistry  parameters.Unpredictable  effects  for  carbon  monoxide,  lactate,  CK,  CKMB,  and  PT/INR.Currently,  interference  has  not  been  documented  in  serum  tests  for  Na,  K,  Cl,  Ca,  BUN,  and  GGT  (gamma-glutamyltransferase).Hydroxocobalamin  has  been  reported  to  falsely  trigger  the  automated  blood  leak  detector  in  some  ...
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/19
UR  - accessmedicine.mhmedical.com/content.aspx?aid=1179992962
ER  -