TY  - CHAP
M1  - Book, Section
TI  - ANTIVENOM, CROTALINAE (RATTLESNAKE)
A1  - Clark, Richard F.
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.  The  older  equine-based  product,  Antivenom  Crotalinae  Polyvalent  (Wyeth-Ayerst),  is  no  longer  produced  in  the  United  States  and  it  has  been  replaced  by  the  ovine-based  Crotalinae  polyvalent  immune  Fab  (CroFab,  Protherics).To  produce  this  antivenom,  sheep  are  hyperimmunized  with  pooled  venom  from  four  North  American  snakes:  Crotalus  adamanteus,  Crotalus  atrox,  Crotalus  scutulatus,  and  Agkistrodon  piscivorus.  Papain  is  added  to  the  pooled  serum  product  collected  from  the  donor  animals  to  cleave  the  immunogenic  Fc  fragment  from  the  IgG  antibody.  The  result  is  an  affinity-purified  Fab  fragment  antivenom.  After  administration,  the  antivenom  is  distributed  widely  throughout  the  body,  binding  to  venom.Indications.  Antivenom  is  used  for  the  treatment  of  signs  and  symptoms  of  envenomation  by  Crotalinae  species  (Table  III–4  and  Snakebite).Contraindications.  Known  hypersensitivity  to  sheep  or  sheep  serum,  or  to  papain  or  papayas.Adverse  effectsImmediate  hypersensitivity  reactions  (including  life-threatening  anaphylaxis)  are  rare  but  may  occur,  even  in  patients  with  no  history  of  animal  serum  sensitivity.  Skin  testing  is  not  indicated  with  CroFab.Mild  flushing  and  wheezing  is  rare  but  can  occur  within  the  first  30  minutes  of  intravenous  administration  and  often  will  decrease  after  the  rate  of  infusion  has  been  slowed.Delayed  hypersensitivity  (serum  sickness)  used  to  occur  in  many  patients  who  received  the  whole-IgG  equine  antivenom.  CroFab  administration  can  also  lead  to  delayed  hypersensitivity  reactions,  but  these  are  rare.Use  in  pregnancy.  FDA  Category  C  (indeterminate;  see  Table  III–1).  There  are  no  data  on  teratogenicity.  Anaphylactic  reaction  resulting  in  shock  or  hypoxemia  in  the  mother  could  conceivably  adversely  affect  the  fetus.  However,  severe  snake  envenomation  of  the  mother  should  be  treated  aggressively  to  limit  venom  effects  that  could  affect  the  fetus  or  placenta.Drug  or  laboratory  interactions.  There  are  no  known  interactions.Dosage  and  method  of  administration.  The  initial  dose  is  based  on  the  severity  of  symptoms,  not  on  body  weight  (see  Table  III–4).  Children  may  require  doses  as  large  as  or  larger  than  those  for  adults.  The  end  point  of  antivenom  therapy  is  the  reversal  of  systemic  manifestations  (eg,  shock,  coagulopathy,  and  paresthesias)  and  the  halting  of  progressive  edema  and  improvement  in  pain.  In  some  severe  cases,  large  quantities  of  antivenom  may  be  required  (eg,  4–6  vials  every  hour),  and  laboratory  blood  clotting  parameters  may  be  refractory  to  even  large  doses.  However,  most  cases  can  at  least  be  stabilized  with  aggressive  antivenom  therapy.  Antivenom  may  be  effective  even  if  given  up  to  several  days  after  envenomation.Treat  all  patients  in  an  intensive  care  or  monitored  setting.Before  antivenom  administration,  insert  at  least  one  and  preferably  two  secure  intravenous  lines.Reconstitute  each  lyophilized  vial  of  CroFab  antivenom  with  the  10  mL  of  diluent  provided  or  sterile  saline  and  gently  swirl  to  solubilize  the  material.  Avoid  shaking,  which  may  destroy  the  immunoglobulins  (as  indicated  by  foam  formation).  Further  dilution  with  normal  saline  may  facilitate  solubilization.  Reconstituted  product  should  be  used  within  4  hours.Administer  antivenom  by  the  intravenous  route  only.  Start  slowly,  increasing  the  rate  as  tolerated.  The  infusion  of  4–6  vials  of  CroFab  should  be  completed  over  60  minutes,  but  the  infusion  rate  may  be  increased  or  decreased  as  tolerated  and  clinically  indicated.If  there  is  ...
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/24
UR  - accessmedicine.mhmedical.com/content.aspx?aid=1174607345
ER  -