Applied ANS Flashcards
Provide examples of the Indirecting Anticholinesterase agents that are reversible.
Neostigmine
Pyridostigmine
Indirect acting irreversible Anticholinesterase agents.
Organo Phosphorus Compounds.
What are the signs of too much ACh?
SLUDE
salivation, lacrimation, urination, diarrhoea, gastric
DUMBELS - diarrhoea, urination, miosis, bronchoconstriction, skeletal excitation, lacrimation and salivation/sweating.
Describe how organophosphate poisoning works.
Drug binds covalently to cholinesterase enzyme. New enzyme has to be synthesised to restore cholinesterase activity which takes several weeks.
Describe Myasthenia Gravis
an autoimmune disorder, is characterized by weakness and fatiguability of skeletal muscles. It is caused by autoantibody mediated dysfunction at the NMJ.
SIgns of Myasthenia Gravis.
Drooping eyelid
included diplopia, ptosis and dysarthria (oculobulbar form)
How can diagnose Myathenia Gravis?
Dx can be confirmed by using neostigmine (in South Africa) Edrophonium (short acting, reversible anticholinesterse).
What is the treatment of Myasthenia Gravis?
Pyridostigmine/neostigmine used in mild to moderate disease
How do you treat cholinergic side effects–> Cholinergic Toxidrome?
anticholinergic drug/cholinergic antagonist. (Such as glycopyrollate).
How does Clonidine (antihypertensive) work?
lowers BP by binding to presynaptic alpha 2 receptors with inhibition of the release of NA (which acts are vasoconstrictor).
Describe the effects of the inhibition of the release of ACh from vesicles.
Inhibition of sweating, giving symptoms of a dry, warm skin
Inhibition of salivation with symptoms of dry mouth
Pupillary dilatation
Provide examples of aminoglycosides that can inhibit the release of ACh on from the vesicles.
Streptomycin and neomycin
What are the sides effects of aminoglycosides and where is it contraindicated?
NMBlockade and respiratory paralysis, especially if given soon after anaesthesia or muscle relaxants.
In Myasthenia Gravis
How does Botox work?
blocks release of ACh at sweat glands (reduced sweating), and at NMJ (muscle paralysis)
What is the deadly triad of organophosphate poisoning?
BBB
Bronchorrhoea
Bronchoconstriction
Bradycardia
How does the inactivation of ACh occur?
cholinesterase
suxamethonium
Explain the effects Suxamethonium.
It is a muscle relaxant, that blocks the depolarization of the cells.
What is used to inactivate the suxamethonium?
Butyrylcholinesterase also called pseudocholinesterase found in liver, brain and GIT.
Describe Atropine.
Tertiary amine with competitive binding to muscarinic receptors
Treatment of organophosphate poisoning
Antispasmodic, antisecretory, mydriasis and cycloplegia
Describe glycopyrrolate.
Quaternary amine, preoperative medication
Ophthalmology to produce mydriasis and cycloplegia
Used in perioperative medicine to prevent secretions, bronchoconstriction and bradycardia
Describe Ipratropium Bromide.
cholinergic stimulation causes bronchospasm, therefore anticholinergic acts as bronchodilator
Describe Oxybutinin.
cholinergic stimulation of bladder leads to detrusor muscle contraction, therefore blocking cholinergic stimulation will have urinary antispasmodic effect.
What is the side effects of Imipramine (TCA)?
strong antimuscarinic action, reduced bladder contraction, reduces incontinence
Examples of drugs that are Antimuscuranic
M1-selective: Pirenzepine
Non-selelctive-atropine
Examples of drugs that are antinicotinic.
Ganglion blockers- hexamethonium
Neuromuscular blockers- tubocurarine