Contents
Introduction
Propofol is a drug widely used for sedation and general anaesthesia.
It also gained notoriety for its involvement in the death of Michael Jackson.
It usually comes in a solution of 200mg in 20mls and easily recognisable compared to most other drugs, as it is lipid soluble, and not water soluble, and therefore, comes as a white coloured opaque solution.
Metabolism
The majority by the liver, but metabolism appears to be quicker than be accounted for by hepatic blood flow, and other, unknown pathways are probably also involved.
It is metabolised to water-soluble compounds which are then excreted by the kidney.
Onset
Onset of propofol is typically very quick, around 1-2 minutes, and is in-keeping with its brain-arm time.
Duration of Action and Half-life
The duration of action for propofol is brief, around 4-8 minutes. In comparison, its half-life is relatively long, and is somewhere between 2-24 hours. This difference occurs because propofol is rapidly absorbed by peripheral tissues (particularly fat) and
Dose
Dosages very widely. In paediatrics, a common dose is 1-3mg/Kg/hour for general anaesthesia, and a similar rule of thumb applies in adults.
In situations where only a very short period of anaesthesia, or only a partial sedation is required, then the dose is often titrated. Such situations might include DC cardioversion, gastroscopy or conolonscopy or perhaps reduction of a fracture or displaced limb in the emergency department. In these instances, an initial dose of 0.5 – 1mg/Kg may be given, and titrated with further regular boluses, every 1-2 minutes to effect. Close airway monitoring is required in such patients, and if too large a dose is given, then airway management may be required until the drug wears off.
Contraindications
- Hypersensitivity to propofol
- Hypersensitivity to eggs
- Hypersensitivity to soy
Effects
- Sedation
- Induction of anaesthesia
- Anti-epileptic
- Hypotension
- Arrythmia
- Tachycardia
- Reduced cardiac output
Interactions
Propofol requirements are reduced by concomitant use with benzodiazepines and / or opioids
Reversal Agents
None
