Anticholinesterase Flashcards
Name the anticholinesterase drug that is a tertiary amine:
Physostigmine
Name the anticholinesterase drugs that are Quaternary ammonium:
- Edrophonium
- Neostigmine
- Pyridostigmine
Anticholinesterase enzyme inhibition does:
- inhibit acetylcholinesterase
- Result in increased availability of acetylcoline.
What happens when actylcholinesterase and Neostigmine/Pyridostigmine come together:
- Hydrolyzed by acetylcholinesterase
- Carbamylates the enzyme in the process
- Block enzyme’s ability to hydrolyze Ach
What happens when actylcholinesterase and edrophonium come together:
Forms a reversible electrostatic attachment
The absence of neuromuscular blockers, acetylcholinesterase inhibitors may produce fasiculations: (What is this called)
Presynaptic Effect
At doses greater than usual clinical doses, anticholinesterase drugs have been reported to produce some form of neuromuscular blockade: (What is this called)
Direct Effect
_________ inhibition electrostatic attachment to the anionic site (Edrophonium)
Reversible
_________ of _______ _______ are reversible formation of carbamyl ester complexes at the esteratic site (Neostigmine, pyridostigmine, physostigmine)
Formation, Carbamyl, Esters
___________ inhibition is when Organophosphates combine with the esteratic site to form a stable inactive complex
Irreversible
T/F: Anticholinesterase drugs have no significant differences in patients with normal renal function.
True
What is the onset of action for edrophonium:
1-2 minutes
What is the onset of action for neostigmine:
7-11 minutes
What is the onset of action for pyridostigmine:
up to 16 minutes
What is the duration for action of anticholinesterase drugs
All are the same (60-120 minutes)
What kind of pharmacological effects will be seen with anticholinesterase:
- Bradycardia
- Salivation,
- Bronchoconstriction
- Miosis,
- Hyperperistalsis
- PONV
What kind of pharmacological effects will be seen with nicotinic:
-Act at the neuromuscular junction and autonomic ganglia
T/F: Neostigmine and pyridostigmine, but not edrophonium, produce marked and prolonged inhibition of plasma cholinesterase.
TRUE
What clinical use does anticholinesterase drugs have:
-Reversal of neuromuscular (antagonist)
-Treatment of mysthenia gravis
(Increases ACh at the neuromuscular junction)
-Treatment of glaucome (cause miosis)
-post op analgesia
-post op shivering
Antagonist-assisted reversal of NMB:
- Increase the availability of ACh at the NMJ
- Acts presynaptic and postsynaptic
- Administered during the time of spontaneous recovery from NMB
What is the dosage for Edrophonium:
0.5 mg/kg
What is the dosage for neostigmine:
0.043 mg/kg
What is the dosage for pyridostigmine:
0.21 mg/kg
What does potency depend on for anticholinesterase drugs:
- NMB being antagonized
- Speed of spontaneous recovery
- Depth of NMB when the reversal is initiated
- End point selected
Mixture with a anticholinergic and anticholinesterase will have what effect:
- Reversal requires only nicotinic effects
- Muscarinic effects blocked with an anticholinergic drug
- Administer anticholinergic with a faster onset than anticholinesterase to minimize bradycardia
T/F: Once acetylcholinesterase is maximally inhibited, additional anticholinesterase does not further antagonize the neuromuscular blockade.
True
What must be seen before administration of anticholinesterase drug:
Twitch height has recovered to > 10 %
What factors can/will influence reversal of neuromuscular blockade:
- Nondepolarizing neuromuscular blocking drug
- Intensity of NMB
- Antibiotic
- hypothermia
- respiratory acidosis (PaCO2 > 50%)
- hypokalemia
- metabolic acidosis
What are some basic on Physostigmine:
- Tertiary amine that crosses the BBB
- Antagonizes adverse CNS effeccts of certain drugs
What is the dose for Physostigmine:
0.015 to 0.06 mg/kg IV
Acute overdose of physostigmine will have what type of effects on muscarinic:
- Miosis and difficulty focusing
- Salivation
- Bronchoconstriction
- Bradycardia
- Abdominal cramps
- Loss of bowel and bladder control
Acute overdose of physostigmine will have what type of effects on nicotinic:
Skeletal muscle weakness to paralysis and apnea
What type of CNS effects will be seen with physostigmine acute overdoes:
- Confusion
- Ataxia
- Seizures
- Coma
- Depressed ventilation
What would be organophsphate anticholinesterases:
- insecticides
- nerve agents
T/F: Organophosphates are lipid soluble and can cross the BBB.
True
What is the reversal for anticholinesterase overdose:
- Atropine (Antimuscarinic effect)
- Pralidoxime (Acetylchoinesterase reactivator)
- Supportive measures
