• Know ketamine well – important ED drug. Know PK, PD and toxicities.
  1. Phencyclidine derivative
  1. NMDA receptor antagonist. It is the only IV anaesthetic agent that has significant analgesic properties
  2. Organ system effects as follows:
    • CNS
      • It is a cerebral vasodilator and tends to increase cerebral blood flow and cerebral metabolic rate. Therefore, it is contra-indicated in RICP.
      • May be used for status epilepticus if other means are unsuccessful.
      • Emergence phenomenon – tends to be less severe and of lower incidence in children. Premedication with BZD may decrease incidence.
    • CVS
      • It produces transient by significant centrally mediated stimulation, therefore increasing HR and cardiac output.
      • It is thought to be a direct myocardial depressant, and this property may become apparent in the patients that are critically ill and have limited ability to increase their sympathetic drive.
    • Respiratory
      • Transient apnoea and hypoventilation if large dose given rapidly.
      • Importantly – causes lacrimation and salivation. May cause laryngospasm in children.
      • Relaxes bronchial s/m: consider in severe asthma
      • If used as a single drug, the respiratory response to hypoxia and hypercapnia is NOT affected
  1. IV or IM.
  2. Can be given as bolus/infusion
  1. Very lipid soluble
  2. Only IV anaesthetic agent that has low protein binding
  3. Large Vd – 3L/kg
  1. Metabolised in the liver to norketamine (an active metabolite) and then conjugated to water soluble metabolites and excreted in the urine.
    • Distribution T ½: 11-16 minutes
    • Elimination T ½ : 2-4 hours
    • Duration of action: 5-10 minutes
  1. Urine
  1. Procedural sedation (Very useful in children – give IM)
  2. Intravenous anaesthetic for induction
  3. Pain management
  1. Head injury and RICP are absolute CI.
Special precautions
Adverse events
  1. Salivation/bronchorrhoea, leading to laryngospasm
  2. Emergence phenomena
  3. RICP
  1. 1-2mg/kg if induction
  2. Pain dose is 0.1mg/kg, infusion is 0.1mg-0.3mg/kg
  3. 4mg/kg IM if procedural sedation
Withdrawal syndrome
Special notes