Ketamine Flashcards
1
Q
What is ketamine?
A
Phencyclidine derivative
2
Q
What forms is ketamine available in?
A
Colourless solution in glass vial
10/50/100 mg/ml
Racemic mix or as S(+) enantiomer (less delirium)
IV/IM/PO/PR/intrathecal/epidural
3
Q
What are the induction vs analgesic doses of ketamine?
A
1-2 mg/kg IV
5-10 mg/kg IM
Analgesic -0.2-0.5 mg/kg
4
Q
What are the chemical properties of ketamine?
A
Water soluble forming acidic solution pH 3.5 - 5.5
5
Q
What is the absorption/distribution of ketamine?
A
- well absorbed orally and IM
- oral bioavailability 20%
- protein binding 20-50%
- Vd 3L/kg
- t1/2 2.5hrs
6
Q
What is the metabolism/excretion of ketamine?
A
- metabolised in the liver by p450 to norketamine (30% potency)
- norketamine metabolised by conjugation to inactive compound
- excreted in urine
7
Q
What are the uses of ketamine?
A
- induction of anaesthesia especially in refractory asthma due to profound bronchodilator effects
- sedation in ICU/for short procedures
- analgesia in military field
- in neuroaxial blockade to prolong it’s effect
- drug of abuse
8
Q
What is the MOA of ketamine?
A
- non-competitive antagonist at NMDA receptors
- antagonist at MOP receptor, antagonist at KOP and DOP receptors (no interaction with GABA)
9
Q
What are the CVS effects of ketamine?
A
- increased noradrenaline and adrenaline release
- tachycardia
- increased CO
- increased BP
- increased cardiac O2 consumption
10
Q
What are the RS side effects of ketamine?
A
- increased resp rate
- no decreased laryngeal reflex
- airway maintained
- profound bronchodilation
11
Q
What are the CNS effects of ketamine?
A
- dissociative anaesthesia (ie strong analgesic and light sleep)
- increased cerebral blood flow
- increased ICP
- increased CMRO2
- increased IOP
- amnesia
- emergence phenomena
- delirium, hallucinations
- increased muscle tone
12
Q
What are the GI SEs of ketamine?
A
- nausea and vomiting
- salivation
13
Q
A
