Autonomics + acetylcholinesterase inhibitors Flashcards
What is the neurotransmitter for the parasympathetic nervous system?
Acetylcholine
What are the two kinds of cholinergic receptors?
Muscarinic
Nicotinic
What do nicotinic receptors do?
Autonomic ganglia
Skeletal muscle
What do the muscarinic receptors stimulate?
End-organ effector cells in bronchial smooth muscle, salivary glands, and SA node
Which drugs block nicotinic receptors?
Neuromuscular blockers
Which drugs block muscarinic receptors?
Anticholinergics
What is carbachol?
Topical anticholinergic used for wide angle glaucoma
How do acetylcholinesterase inhibitors work?
By binding to the enzyme.
The type of bond determines the duration
What are organophosphates?
A class of acetylcholinesterase inhibitors that form irreversible binds to the enzyme
What kind of bond does neostigmine form?
Covalent
What kind of bond does edrophonium make?
Electrostatic and hydrogen (short-lived)
What kind of bond does pyridostigmine make?
Covalent
What other mechanisms does neostigmine have?
Directly activate nicotinic receptors (weakly)
Causes mor mobilization of acetylcholine
What may happen with high dosages of these drugs?
Potentiation of nondepolarizing blockade
What do acetylcholinesterase inhibitors do to succinylcholine blockade?
Prolongs it
What are the acetylcholinesterase inhibitors effects on CV?
Bradycardia and asystole
What are the pulmonary effects of acetylcholinesterase inhibitors?
Bronchospasm
Increased secretions
What are the GI effects?
Increases peristalsis
Increased salivation
fecal and urinary incontinence
How are acetylcholinesterase inhibitors metabolized?
25-50% in the liver
How are the acetylcholinesterase inhibitors excreted?
50-75% in urine
Why doesn’t neostigmine cross the bbb?
It has a quaternary ammonium group
What is the maximum recommended dose of neostigmine?
.08 mg/kg up to 5 mg
When is the peak effect of neostigmine?
10 minutes
When can you first see signs of neostigmine working?
5 minutes
What is the duration of action of neostigmine?
1 hour
What is the onset of action of glycopyrrolate
5-10 minutes
Does neostigmine cross the placental barrier?
Yes –> fetal bradycardia
What anticholinergic should you use in a pregnant patient getting neostigmine?
Atropine
Are neostigmine and pyridostigmine lipid soluble?
No
What is this dosage of pyridostigmine?
0.25 mg/kg
What is the onset of action of pyridostigmine?
10-15 minutes
What is the duration of action of pyridostigmine?
2 hours
How much glycopyrrolate should you give with pyridostigmine?
0.05 mg per 1 mg
What is the dosing of physostigmine
.01-.03 mg/kg
How is physostigmine useful?
It reverses some of the CNS depression and delirium associated with BZDs and volatile anesthetics
Can help post op shivering
Partially antagonizes morphine induced respiratory depression
How is physostigmine metabolized?
Plasma esterases
How is sugammadex eliminated?
Unchanged in urine
What is the dosage of sugammadex?
4-8 mg/kg
What is L-cysteine?
An endogenous amino acid that is often added to TPN regimens to enhance calcium and phosphate solubility.
Which neuromuscular blockers does L-cysteine work on?
Gantacurium (fumarate) ultra-short acting
How does L-cysteine work?
Forms more inactive metabolites through adduct formation
What is the duration of atropine?
15-30 minutes
What acetylcholinesterase inhibitor should it be paired with?
Edrophonium
What is the duration of glycopyrrolate?
2-4 hours
What is the duration of neostigmine IV?
4-6 hrs
What is the onset of IV neostigmine?
7-11 minutes
What is IV scopolamine given for?
Amnesia in hemodynamic ally unstable patients
What drug should be used for scopolamine delirium/overdose?
Physostigmine
