Ketamine
| Distribution | 1-3L/kg |
| Target receptor | NMDA receptor |
| Mechanism of action | Lodges in the pore of the NMDA cation channel, causing the receptor to become closed, and to stop binding glutamate. - prevents glutamate-simulated sodium and calcium influx into the cell, and potassium efflux - depressed excitatory neurotransmission |
| Metabolism | Metabolised by CYP450 enzymes into multiple metabolites, of which only norketamine is mildly active. Hepatic |
| Elimination | Elimination half-life is 2.5 hrs, but redistribution (alpha) half-life is ~ 7-11 minutes |
adverse effects
- hypersalivation
- laryngospasm
- tachycardia, ↑ ICP
Toxicity
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Nephrotoxicity - papillary necrosis with chronic exposure
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Anaesthesia:
- Induction dose 1-2 mg/kg IV
- Maintenance dose 30-90 mcg/kg/min (less common)
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Analgesic agent:
- Small bolus doses of 10-20mg