RT Book, Section
A1 Armenian, Patil
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.
SR Print(0)
ID 1174607467
T1 KETAMINE
T2 Poisoning & Drug Overdose, 7e
YR 2018
FD 2018
PB McGraw-Hill Education
PP New York, NY
SN 9780071839792
LK accessmedicine.mhmedical.com/content.aspx?aid=1174607467
RD 2024/04/19
AB Pharmacology.  Ketamine,  an  arylcylohexylamine  dissociative  anesthetic  agent  similar  to  phencyclidine  (PCP),  is  widely  used  as  an  induction  agent  for  rapid  sequence  intubation  (RSI)  and  in  pediatric  procedural  sedation.  It  is  a  racemic  mixture,  and  the  S  isomer  is  more  potent  with  a  shorter  duration  of  action.  The  analgesic  and  dissociative  effects  are  mediated  through  N-methyl-d-aspartate  (NMDA)  receptor  antagonism.  Sympathomimetic  effects  are  mediated  through  inhibition  of  reuptake  of  dopamine,  norepinephrine,  and  serotonin  in  the  brain;  these  effects  may  contribute  to  its  cardiovascular  side  effects  as  well  as  potential  therapeutic  benefit  for  patients  with  depression.  Additionally,  ketamine  binds  to  mu-,  delta-,  sigma-,  and  kappa-opioid  receptors  contributing  to  its  analgesic  effects.  Other  pharmacologic  effects  mediated  via  epigenetic  modulation  and  expression  of  microRNA,  inflammatory  mediators,  and  nitric  oxide  synthase  may  mediate  its  sustained  therapeutic  effects  for  the  management  of  psychiatric  and  mood  disorders,  anti-inflammatory  actions,  and  treatment  of  status  asthmaticus.  Ketamine  is  well  absorbed  via  the  intramuscular  route  and  is  metabolized  in  the  liver  to  an  active  metabolite  norketamine.  It  has  poor  oral  (16%)  and  variable  intranasal  (25-50%)  bioavailability.  The  relatively  high  lipid  solubility  and  low  protein  binding  facilitate  rapid  uptake  into  the  brain  with  a  rapid  onset  of  action,  which  may  occur  30  seconds  after  intravenous  administration  and  3  minutes  after  intramuscular  administration  and  lasting  up  to  10  and  25  minutes,  respectively.  The  serum  half-life  is  2–3  hours.IndicationsInduction  agent  for  rapid  sequence  intubation  (RSI).  Ketamine  may  be  used  to  facilitate  sedation  for  endotracheal  intubation,  especially  in  trauma  patients  and  hypotensive  patients.Procedural  sedation.  Ketamine  can  produce  sedation  and  amnesia  with  minimal  respiratory  depression.Analgesia.  Low-dose  ketamine  has  been  used  alone  or  with  opioids  for  analgesia  in  emergency  department,  postoperative,  and  cancer-associated  pain.Agitation.  Ketamine  may  be  used  as  a  sedating  agent,  either  alone  or  in  combination  with  midazolam,  although  this  use  has  not  been  thoroughly  studied  in  emergency  department  patients.Other  potential  indications  include  postanesthetic  shivering,  complex  regional  pain  syndrome,  status  asthmaticus,  depression  and  mood  disorders,  suicidal  ideation,  refractory  status  epilepticus,  and  opioid  and  alcohol  withdrawal.ContraindicationsKnown  hypersensitivity  to  the  drug.Do  not  use  in  infants  younger  than  3  months  due  to  propensity  for  airway  adverse  events.Use  with  caution  in  patients  with  high  blood  pressure  or  when  elevation  of  blood  pressure  is  unwanted.Use  with  caution  if  ketamine-induced  increased  intraocular  pressure  could  cause  acute  complications  (eg,  in  a  patient  with  a  ruptured  orbit).Adverse  effectsEmergence  reactions  (dreamlike  states,  vivid  imagery,  hallucinations)  or  recovery  agitation  has  been  reported  with  variable  incidence,  ranging  from  0%  to  36%.  Premedication  with  intravenous  midazolam  minimizes  this  risk.Laryngotracheal  spasm  is  rare,  occurring  in  0.3%  of  children.  The  effect  is  temporary  and  usually  responsive  to  bag-valve-mask  ventilation.Transient  apnea  or  respiratory  depression  is  also  rare,  occurring  in  0.8%  of  children  and  less  so  in  adults.  It  is  more  common  with  rapid  IV  infusions  and  prevented  by  slow  IV  administration  over  at  least  60  seconds.Hypertension;  hypersalivation;  emesis  (7-26%);  muscular  hypertonicity;  random,  purposeless  movements;  clonus;  and  hiccupping  may  occur.Ketamine  is  a  potential  drug  of  abuse.  Long-term  users  may  develop  cystitis  or  bladder  problems  and  a  decline  in  mental  health  (cognitive  impairments,  psychotomimetic  effects).Use  ...