Ketamine Flashcards
Ketamine Mechanism of Action
• Ketamine is an analgesic. It has complex actions, but is predominantly an N-methyl-d-aspartate (NMDA) receptor antagonist (blocker), resulting in
inhibition of excitatory neurotransmitters in the brain.
• Low doses cause analgesia, larger doses cause amnesia and dissociation, and high doses cause anaesthesia.
Ketamine ILS Scope of practice
Analgesia
Under consultation - Dissasociation
Ketamine Indications
- Severe pain (in addition to other medicines), particularly musculoskeletal or burn pain that has not been adequately controlled with an opiate.
- Inducing dissociation, for example for cardioversion, joint relocation or limb alignment.
- Agitated delirium causing a severe to immediately life-threatening risk to safety.
- Rapid sequence intubation (RSI).
- Significant movement during CPR that is interfering with resuscitation.
- Asthma with severe agitation that is impairing the ability to safely provide treatment and/or transport.
Ketamine Contraindications
Known severe allergy.
Aged less than one year.
Ketamine Cautions (7)
- Unable to obey commands. Ketamine will reduce the level of consciousness.
- Active psychosis. Ketamine may make this worse.
- Hypertension. Ketamine may make this worse.
- Clinical conditions that may be made worse by hypertension, for example haemorrhagic stroke.
- Current myocardial ischaemia. Ketamine may increase myocardial oxygen demand.
- Concurrent administration of sedatives or midazolam - this will increase and prolong the effects.
- Elderly and/or frail. These will increase and prolong the effects.
Ketamine Use in pregancy/breastfeeding
Safety has not been demonstrated during pregnancy, but ketamine should be administered if indicated.
• May be administered if the patient is breastfeeding. Advise the patient to stop breastfeeding and seek further advice from their lead maternity carer or GP.
Ketamine Analgesic dose
For analgesia:
a) 30mg IV over approximately 15 minutes if the patient weighs greater than 80 kg. Repeat as required.
b) 20 mg IV over approximately 15 minutes if the patient weighs 50-80 kg. Repeat as required.
c) See the paediatric drug dose tables for a child and administer IV over approximately 15 minutes.
d) 0.5mg/kg IM or PO (up to a maximum of 50 mg) if IV access cannot be obtained. This may be repeated once after 20 minutes.
Ketamine Disassociative Dose
For dissociation:
a) 1 mg/kg IV (up to a maximum of 100 mg). This may be repeated once after five minutes.
b) 2 mg/kg IM (up to a maximum of 200 mg) if IV access cannot be obtained.
This may be repeated once after 20 minutes.
c) See the paediatric drug dose tables for a child.
Ketamine Severe agitated delirium dose
a) 1 mg/kg IV (up to a maximum of 100 mg) every five minutes as required, or
b) 400 mg IM if the patient weighs greater than 80 kg, or
c) 200 mg IM if the patient weighs 50-80 kg.
d) The IM dose may be repeated once after 20 minutes.
Ketamine Significant movement during CPR that is interfering with resuscitation dose
Administer 1 mg/kg (up to a maximum of 100 mg) of ketamine IV once.
Ketamine Analgesic administration - push dose
Dilute 100 mg (1 ml) of ketamine in a 100 ml bag of 5% glucose. Shake well and label:
a) For adults: draw up the dose and administer 2 mg (2 ml) every 1-2 minutes.
b) For children: draw up the dose, dilute the volume further to a total of 20 ml
and administer 2 ml every 1-2 minutes.
Ketamine Analgesic administration - Infusion
Adults or children weighing over 40 kg only, place the
analgesia dose into a 100 ml bag of 5% glucose and infuse over approximately
15 minutes:
a) 2-3 drops/second via a standard IV administration set will deliver 100 ml
over approximately 15 minutes.
b) The administration set will need to be flushed with 0.9% sodium chloride to ensure that all of the ketamine has been administered (around 20ml)
Ketamine Disassociation dose administration (IV)
Dilute 100 mg (1 ml) to a total of 10 ml and
administering the dose as an IV bolus.
Ketamine PO Adminstration
The PO route should be reserved for the very unusual circumstance in which IM injection is contraindicated or not feasible. Administer ketamine PO undiluted in a liquid, for example paracetamol syrup or water.
Ketamine IM Administration
The IM route is preferred over the PO route as IM absorption is more reliable.
Administer IM ketamine undiluted. The preferred site is the lateral thigh as this has the best absorption. If this site is not suitable use the lateral upper arm.
