Induction Drugs-(Propofol) (Ex 2) Flashcards
(42 cards)
For Propofol, what are the doses for:
1. Induction
2. Maintenance
3. Conscious sedation
- Induction = 1.5 - 2.5 mg/kg IV
- Maintenance = 100 - 300 μg/kg/min
- Conscious sedation = 25 - 100 μg/kg/min
What is the concentration of a 1% solution?
- 10mg/mL
What are the inactive ingredients in propofol? Why is one particularly important?
- 1.2% Lecithin (from egg yolks) can cause anaphylaxis with egg allergies.
- 2.25% glycerol
- 10% soybean oil
What are the disadvantages of propofol’s inactive ingredient composition?
- ↑ bacterial growth
- ↑ plasma triglycerides with prolonged infusions
- Pain on injection
Differentiate Ampofol and Aquavan.
- Ampofol - low-lipid, no preservative that burns on injection more often.
- Aquavan - prodrug with less injection pain but causes dysesthesias. Slower onset, larger Vd, and high potency.
What is the mechanism of action of propofol?
- GABA-A receptor modulator that increases Cl⁻ conductance.
How does propofol cause immobility through spinal cord-depression?
- Trick question. Immobility from propofol is not from drug-induced spinal cord depression.
What are the clearance characteristics of propofol?
The clearance of propofol from plasma exceeds hepatic blood flow.
What metabolizes propofol?
- Hepatic CYP450 enzymes and excreted by kidneys.
What is the E ½ time of propofol?
- 30 - 90 minutes
What is the context-sensitive half-time of propofol? Is this a relatively low or high context half-time?
- 40 minutes (for an 8 hour infusion)
- Low CS ½ time.
What are the following characteristics of propofol:
1. Elimination ½ time.
2. Volume of distribution
3. Clearance (mL/kg/min)
- E ½ time = 30 - 90 minutes
- Vd = 3.5 - 4.5
- Clearance = 30 - 60 mL/kg/min
Differentiate blood pressure and heart rate changes that occur with propofol vs thiopental.
- Propofol: ↓BP & ↓HR
- Thiopental: ↓BP & ↑HR
Does propofol cross the placenta? What are the consequences of this?
- Yes but is rapidly cleared from neonatal circulation.
Do cirrhosis and renal dysfunction have significant effects on propofol metabolism?
No significant impact
What drug is the induction drug of choice?
Propofol
What is the induction dose of propofol in adults? Children?
- Adults: 1.5-2.5 mg/kg IV
- Pediatrics: higher doses due to larger central volume and clearance rate.
What is the induction dose of propofol in the elderly?
25 - 50% lower than regular adult
What plasma propofol levels would correlate with unconsciousness?
What about awakening?
- Unconscious: 2 - 6 μg/mL
- Awake: 1 - 1.5 μg/mL
What is the conscious sedation dose of propofol?
- 25 - 100 μg/kg/min
What are the anesthetic characteristics of propofol in the context of conscious sedation?
- Minimal analgesia but has anti-convulsive and amnestic properties.
- Prompt recovery w/ low residual sedation
- ↓ risk of PONV
- Midazolam or opioids as adjuncts.
What are the anti-emetic properties of propofol?
Why is this thought to occur?
- Very anti-emetic (more effective than ondansetron)
- Direct depressant of vomiting center
What is the sub-hypnotic dosing for propofol?
- 10 - 15 mg IV, followed by 10 mcg/kg/min
What is the anti-pruritic dosing of propofol?
- 10 mg IV
