QUESTIONS AND SOLUTIONS RATED A+
✔✔Neostigmine is a... - ✔✔cholinesterase inhibitor that reversibly binds to
acetylcholinesterase at the NMJ - this inhibits acetylcholine hydrolysis allowing more
ACh to compete with the NMBA at the nicotinic receptor
- competitve antagonism!
✔✔Produces reversible inhibition of AchE by forming a carbamyl ester complex at
esteratic site? - ✔✔Neostigmine
pridostigmine
physostigmine
✔✔Forms an electrostatic bond at the anionic site and a noncovalent hydrogen bond at
the esteratic site. - ✔✔Edrophonium
- hydrogen bonds are weak so DoA is short
✔✔Produces non-reversible inhibition of AchE by forming a stable complex with the
esteratic site. New acetylcholinesterase must be synthesized, which explains this
extended DoA.... - ✔✔Organophosphates
✔✔Match the acetylcholinesterase inhibitor to its dose:
Neostigmine
Edrophonium
Pyridostigmine - ✔✔Neostigmine: 0.05mg/kg
Edrophonium 1mg/kg
Pyridostigmine 0.3 mg/kg
✔✔In PACU, 85 year old female received scopolamine and is agitated and confused,
what is the best treatment and why?
dose? - ✔✔physostigmine
- scopolamine crosses the BBB and may cause central anticholinergic syndrome
15-60 mcg/kg - only inhibitor that crosses the BBB, antidote for antimuscarinic OD
✔✔What can central anticholinergic syndrome mimic? - ✔✔slow emergence from
anesthesia
✔✔What 2 acetylcholinesterase inhibitor in clinical use prolongs the DoA of sux? -
✔✔neostigmine
pyridostigmine
,✔✔Onset of action for the following anticholinesterase inhibitors?
edrophonium
neostigmine
pyridostigmine - ✔✔edrophonium: 1-2 min
neostigmine: 7-11 min
pyridostigmine: up to 16 min
✔✔Naturally occurring tertiary amines? - ✔✔atropine
scopolomine
- lipophilic
- easily diffuse lipid membranes like BBB, GI tract and placenta
✔✔Robinul is a ? - ✔✔quaternary ammonium derivate that ionizes in the plasma
- doesn't cross easily
✔✔What is cycloplegia? what causes it? - ✔✔paralysis of the ciliary muscle in the eye,
resulting in the loss of accommodation
Scopolamine +++
Atropine ++
Glycopyrolate 0
✔✔What are phenylpiperidines? - ✔✔fentanyl
sufenta, etc
- synthetic
meperidine
✔✔What are phenanthrenes? - ✔✔morphine, codeine
- naturally occurring
✔✔What is a diphenylpropylamine? - ✔✔methadone
- synthetic
✔✔Semi-synthetic examples - ✔✔morphine derivatives - dilaudid, heroin, naloxone,
naltrexone
thebaine derivatives - oxy
✔✔Mu receptor stimulation causes what physiologic effects? - ✔✔bradycardia
pruritis
respiratory depression
supraspinal AND spinal anes
,euphoria
sedation
miosis
constipation
N/V
increased biliary pressure
urinary retention
✔✔key effects of kappa stimulation - ✔✔dysphoria
antishivering effect
diuresis
✔✔Delta receptors do not mediate what two things? - ✔✔bradycardia
sedation
✔✔A patient becomes hypotensive after 10mg of IV morphine....why? - ✔✔They DO
NOT cause myocardial depression so CV s/e are b/c of:
decreased SNS tone, which means decreased preload, CO and BP...orthrostatic
hypotension and venous pooling
- histamine release
✔✔In women, morphine is associated with a: - ✔✔greater analgesic potency
slower onset of action
longer duration of action
lower postop opioid consumption
✔✔Anesthesia in a healthy 35 yr old with 160 prop, 150 sufenta and 120 sux....one min
later, they become impossible to ventilate...why? - ✔✔BRONCHOSPASM
✔✔Methadone can cause what cardiac problem? - ✔✔QT prolongation
- delays the inward K+ rectifier, increased risk of Torsades
✔✔Most potent opioid agonist? - ✔✔sufenta
✔✔only opioid with pKa (6.5) that is lower than physiologic pH? - ✔✔Alfenta
most of it exists in nonionized form, more penetrates BBB, fastest acting!
✔✔Codeine is metabolized to what by what?
- who is more resistant to codeine therapy? most sensitive? - ✔✔morphine by CYP2D6
- Asians may be resistant to codeine therapy
- Ethiopians are more sensitive
✔✔What opioid is associated with hyperalgesia? (OIH) following discontinuation.
, What can be given to alleviate this? - ✔✔remi
ketamine
magnesium
✔✔The time course of opioid withdrawal is a function of what? - ✔✔the drugs 1/2 life
✔✔Fentanyl and meperidine duration of action? - ✔✔4-5 days
✔✔Morphine and heroin DoA? - ✔✔7-10 days
✔✔Methadone DoA? - ✔✔6-7 weeks
✔✔What opioid inhibits nerve conduction?
What else does it resemble and what are the effects of that? - ✔✔meperidine
similar to LAs and atropine
increased HR and mydriasis
✔✔The endogenous pain modulation pathway is also called the: - ✔✔descending
inhibitory pain pathway
✔✔The periaqueductal grey communicates with what? which does what? - ✔✔the
ventrolateral medulla to indirectly influence pain transmission in the substantia
gelatinosa (Rexed lamina II and III) in the DORSAL horn of the spinal cord
-> rostroventral medulla --> substantia gelatinosa
✔✔What agent is associated with the greatest amt of rostral spread when injected into
the intrathecal space? - ✔✔morphine!
least lipophilic, less diffuses out of the intrathecal space so more of the drug is available
to ascend towards the brain
✔✔What route of morphine admin is associated with reactivation of herpes simplex
labialis virus? - ✔✔epidural
2-5 days after dose administered
usually results in trigeminal nerve distribution on the face (cold sores)