Opioid agonists pt 2 (Ex2) Flashcards
How potent is fentanyl?
- 75 - 125 x morphine.
What is the blood-brain equilibration of fentanyl?
What does this mean?
- 6.4 minutes
- Potent with rapid onset and ↑ lipid solubility.
What percent of fentanyl is subject to lung first-pass effect?
What does this mean?
- 75%
- Drug is taken up into lung tissue and possibly subjected to breakdown via pulmonary esterases.
Where is fentanyl metabolized?
What is its principal metabolite?
- Liver via CYP3A
- Norfentanil
How does fentanyl dosing change for the elderly or liver cirrhosis?
No change in elderly or cirrhotic patients.
Describe what the graph below is showing.
Fentanyl has the greatest context-sensitive half-time of any of the fentanyl derivatives.
What is the analgesia dosage of fentanyl?
Induction dose?
- Analgesia: 1 - 2 μg/kg IV
- Induction: 1.5 - 3 μg/kg IV
1mg of PO fentanyl = ____ mg of IV morphine
5
What is the intrathecal dosage of fentanyl?
25 mcg
What is the adult oral dose of fentanyl?
Pediatric?
- Adult: 5 - 20 mcg/kg
- Peds: 15 - 20 mcg/kg
What is the transdermal dose of fentanyl?
- 75 - 100 μg (18 hours steady delivery)
What cardiovascular side effects should be known about fentanyl?
What CNS side effects should be known?
- ↓BP & ↓CO
- Can cause seizures & modestly increase ICP.
How much more potent is sufentanil than fentanyl?
- 5-12 times more potent.
How much of sufentanil is subject to first pass effects?
- 60% lung first-pass
How much of sufentanil is protein bound? What protein is it bound to?
92.5% α-1 acid glycoprotein bound.
What is the analgesia dose of sufentanil?
- Analgesia: 0.1 - 0.4 μg/kg IV
What is the induction dose of sufentanil?
18.9 mcg/kg IV
What is the potency of alfentanil?
What is its onset?
- 20% as potent as fentanyl
- Onset: 1.4 min (faster than all derivatives except remifentanil)
What is the alfentanil induction dose?
What about laryngoscopy dose?
What about maintenance?
- Induction: 150 - 300 μg/kg IV
- Laryngoscopy: 15 - 30 μg/kg IV
- Maintenance: 25 - 150 μg/kg/hr IV with inhaled anesthetics
What drug can cause acute dystonia when given to a Parkinson’s patient?
Alfentanil
What receptor affinity does remifentanil have?
How potent is it?
selective μ opioid agonist
same potency as fentanyl
What is remifentanil’s structure and why is it important?
Ester Structure = hydrolyzed by plasma & tissue esterases.
- Rapid onset & offset
- Very titratable
- No accumulation
Answer the following characteristics of remifentanil below:
Clearance:
Peak effect:
- Clearance: 3-4L/min (8x faster than alfentanil)
- Peak: 30-60 seconds (fastest fentanyl derivative)
What is the induction dose of remifentanil?
- 1 μg/kg IV over 1 min
What is the maintenance dosing of remifentanil?
- 0.005 - 2 μg/kg/min IV
How potent is hydromorphone?
What dose should be given?
What benefits does hydromorphone have over morphine?
- 5x more potent than morphine
- 0.5mg IV → 1-4 mg total
- No histamine release & no active metabolites.
Why is codeine not given IV?
- Induced hypotension via histamine release.
What is the dose of codeine for cough suppression?
Analgesia?
- Cough: 15mg
- Analgesia: 60mg (= about 5mg morphine)
Which opioid is most cleared?
- Remifentanil (3-4L/min)
Which opioid(s) is/are the most protein bound?
Which is the least?
- Sufentanil, alfentanil, & remifentanil
- Least = morphine
Which opioid is the highest percent non-ionized?
- Alfentanil
Morphine tends to relieve _____ type pain more than _____ type pain.
Dull: sharp
Opioid + N2O or benzos can lead to?
CV depression (CO & BP)
What negative effect does post-op shivering have?
increased metabolic demand 500%
What is the sufentanil intraop dose?
What is the infusion dose?
intraop: 0.3 - 1μg/kg IV
infusion: 0.5 - 1μg/kg/hr IV
What is the metabolism profile for alfentanil? (metabolized by and metabolite)
metabolized by hepatic p450
metabolite: noralfentanil
What is the E1/2 time of remifentanil?
6.3 minutes
How potent is tramadol?
5-10x less than morphine
