Pharmacology Flashcards
Why are obese patients relatively resistant to succinylcholine?
increased butyrylcholinesterase (pseudocholinesterase) levels
Accumulation of which narcotic metabolites is of concern in patients with renal failure?
- hydromorphone-3-glucuronide -> neuro-excitation and cognitive impairment
- morphine-6-glucuronide -> active metabolite
- normeperidine -> seizures
Which drugs are metabolized by butyrylcholinesterase (pseudocholinesterase)?
succinylcholine
mivacurium
physostigmine
organophosphates
[Fat MOPS sux]
Which drugs are metabolized by plasma esterases?
remifentanil
esmolol
ester local anesthetics
succinylcholine
atracurium (also Hoffman elimination)
etomidate (also liver metabolism)
How is lorazepam metabolized?
glucuronidation in the liver (also oxazepam and temazepam)
* no active metabolites *
What factors influence myalgias following succinylcholinc administration?
more common in women
more common with minor surgery
more common with early ambulation
less common in pregnant vs. non-pregnant women (more common in non pregnant)
less common in children and elderly patients (more common in middle age)
less common with greater muscle tone (more common in fatter)
[more common in non-pregnant, fat me]
What metabolic functions are served by the lung?
- conversion of angiotensin I to angiotensin II
- inactivation of bradykinin (by ACE)
- inactivation/uptake of norepinephrine; serotonin; and prostaglandins E1, E2, and F2alpha
How long is a time constant?
The time it would take an exponential process to be complete if the initial rate had continued.
1 time constant: 63% complete
2 time contants: 87.5% complete
3 time constants: 95% complete
What is ED95 in the context of muscle relaxants?
dose needed to decrease twitch height by 95%
What drugs exhibit zero-order kinetics?
ethanol
thiopental
How does renal failure affect volume of distribution? How does this affect drug dosing?
- increases volume of distribution due to decreased plasma binding proteins
- should increase loading dose and dosing interval
How are midazolam and diazepam metabolized?
cytochrome P450 oxidation in the liver
Besides IV administration, which route provides highest plasma levels of midazolam?
intramuscular
Where are opioid receptors predominantly located?
- periaqueductal gray (brainstem)
- amygdala
- corpus striatum
- hypothalamus
- substantia gelatinosa
Which serum proteins bind most drugs?
albumin binds acidic drugs
alpha-1 glycoprotein binds basic drugs
Which opioid side effects are associated with Mu 1 receptors? Mu 2 receptors? Kappa receptors? Delta and sigma receptors?
Mu 1: urinary retention and euphoria. [#1]
Mu 2: constipation, physical dependence, and hypoventilation. [#2]
Kappa: dysphoria and hallucinations. [like KKKetamine]
Delta and sigma: dysphoria。 [DDD]
Which opioids cause significant histamine release?
morphine and meperidine - can cause bronchospasm
Which opioid can cause tachycardia?
meperidine - similar structure to atropine
Which opioid effects do not show tolerance?
miosis and constipation
How is remifentanil metabolism different between adults and infants?
faster in infants
What are the equivalent IV and PO doses of morphine? Hydromorphone?
morphine: 10 mg IV = 30 mg oral
hydromorphone: 1 mg IV = 5 mg oral
Which narcotic has local anesthetic activity?
meperidine
Which narcotic effects are reversed by naloxone? Which are not?
Reversed: respiratory depression, analgesia, pruritis
Not reversed: constipation, nausea/vomitting, muscle rigidity
What is the primary organ for redistribution of propofol when it residtributes from the brain?
skeletal muscle
