Propofol Flashcards
What is the drug classification of propofol? what is used for? What other drug is in this family?
Drug classification: Isopropylphenol
Used as a hypnotic
other drug: Fosppropofol
What is propofol used for? What are the dosages
- Induction of GA (1-2.5 mg/kg)
- For maintenance of GA (100/200 mcg/kg/min)
- for conscious sedation (25-75 mcg/kg/min)
- antiemetic (10-20 mg) or 10 mcg/kg/min)
What are the physiochemical characteristics of propofol?
Chemical: diisopropylphenol
Physiologic: Insoluble in aqueous solution
It is made as an emulsion, soy bean, lecithin, glycerol.
It supports bacterial growth—> use within 6 hours of openings (sepsis and death has been associated to contaminated Propofol use.
What are the pharmacokinetics of propofol? How is it eliminated?
Distribution: Highly lipophilic—> rapid CNS effect followed by re-distribution into more inactive tissue sites
Metabolized: Hepatic metabolism is partial oxidation by CY4503A4 but mostly by CYP450 2B6. Propofol is metabolized into water soluble compounds. Rate of metabolism of Propofol exceeds hepatic blood flow indicating an extrahepatic means of plasma clearence. 30% of bolus is cleared by lungs.
Eliminated: Through Kidneys
What if the wake up time after an induction dose of propofol? what is the onset of action?
duration: 8-10 min
onset: 30 sec to a min
Why is propofol a good candidate for continuos infusion?
- Rapid plasma clearence
- Slow re-distribution from poorly perfused compartments back to central compartment
- brief context sensitive half life
what are the pharmacodynamics of propofol?
Binds to GABAa (Y subunit) opens chloride channel and causes hyperpolarization of cell membrane, no subsequent action potential
what are the effects of propofol on central nervous system?
- Decrease in CBF
- Decrease in cerebral oxygen consumption
- Decrease in intercranial pressure
- Neuroprotective
- Anticonvulsant
What are the effects of propofol on cardiovascular system?
- Causes vasodilatation both in arteries and veins
- Decreases pre-load
- Does not affect cardiac output
- Numbs the baroreflex effect of heart, heart rate will not pick up in response to decrease in bp
- Watch out in elderly as they are already hypovolemic too and now you are causing vasodilation
What are the effects of Propofol on respiration?
- It is a respiratory depressant
- Induction dosecauses apnea
- Infusion will reduce min ventilation by reducing the tidal volume and respiratory rate ( effects tidal volume more)
- Ventilatory response to hypoxia and hypercapnia is reduced
- Reduction in upper airways reflex—> you can use LMA with propofol
- decreases the incidence of wheezing after induction of anesthesia both in healthy and asthmatic patients
What are the other effects of propofol?
- Antiemetic (10-20 mg, 10 Mcg/kg/min)
- DOES NOT enhance the effect of NMBD
- Provided excellent clinical condition for ET without NMBD
What is propofol infusion syndrome?
unexpected tachycardia during propofol anesthesia should require lab eval for possible metabolic acidoisis
what is porpofol used for?
- induction ( 1-2.5 adults) (2.5-3.5 kids)
- Maintenance (100-200 mcg/kg/min)
- conscious sedation (25-75 mcg/kg/min)
- anti-emetic (10-20 mg, 10 mcg/kg/min)
When do you need to reduce the amount of propofol given?
- increasing age
- Reduced cardiovascular reserve
- premed with benzodiazepines and opiods
what is one of the major side effects or propofol?
pain on injection