3. Pharmacologic Cholinergics Flashcards
Drugs with what type of ganglionic target effects all autonomic functions? What is the end result?
Nicotinic (cuz all have preganglionic nicotinic receptor)
The dominant tone in every organ is antagonized
Autonomic drugs can target what different regions?
CNS Acting (signal origin)
Ganglion blockers
(Postganglionic) Neuron blocker
(Distal) Receptor Blocker
What toxin blocks Ach release? What organ can it not effect? Why?
Botulinum toxin
Can’t reach brain because it is a protein
What are the pharmacologic nicotinic ganglionic receptor agonists? Effects? Clinical uses?
Only Nicotine
Receptor stimulation then depression + CNS stimulant (cause of addiction)
Treatment of nicotine withdrawal (oral or transdermal)
What are the pharmacologic nicotinic ganglionic receptor antagonists?
Hexomethonium
Mecamylamine
Trimethapham
Which ganglionic receptor antagonists can penetrate into CNS? Which one can’t?
Mecamylamine
Hexomethonium
What is the treatment of choice for a patient that presents with convulsions due to nicotine overdose?
Mecamylamine (cuz can get into CNS)
What was a previous use for ganglionic receptor antagonists that is no longer indicated due to the high level of side effects?
Hypertension treatment
Effect of ganglionic receptor antagonists on arterioles & veins?
Decrease in symp –> hypotension, postural hypotension & decreased CO
Effect of ganglionic receptor antagonists on the heart?
decreased para –> increased HR = tachycardia
Effect of ganglionic receptor antagonists on the Iris?
decreased para –> pupil dilation = mydriasis
Effect of ganglionic receptor antagonists on the ciliary muscle?
decreased para –> loss of accomodation = cyclopegia
Effect of ganglionic receptor antagonists on GI system?
decreased para –> less tone = constipation
Effect of ganglionic receptor antagonists on the bladder?
decreased para –> urinary retention
Effect of ganglionic receptor antagonists on salivary gland?
decreased para –> dry mouth = xerostomia
Effect of ganglionic receptor antagonists on sweat glands?
decreased symp –> decreased ability to thermo regulate = hypothermia
What are the pharmacologic muscarin agonists?
Choline esters = acetylcholine, methacholine & bethanechol
Alkaloids = muscarine & pilocarpine
In terms of pharmacologic action, what is acetlycholine? Clinical uses?
Muscarinic agonist
Only eye surgery
In terms of pharmacologic action, what is methacholine? Clinical uses?
Muscarinic agonist
Test bronchial reactivity
In terms of pharmacologic action, what is Bethanechol? Clincial uses?
Muscarinic agonist
increase urination
Which pharmacologic muscarinic agonist is metabolized rapidly? Slowly? Not metabolized?
Acetylcholine
Methacholine
Bethanechol
In terms of pharmacologic action, what is pilocarpine? Clinical uses?
Muscarinic agonist
Treat glaucoma or increase salivation
What is the “historical” muscarinic antagonist & its use?
Belladona
Used to cause pupil dilation
Long acting
In high doses, antimuscarinics can cause what CNS signs?
Hallucinations
“Current” protoype antimuscarinic drugs?
Atropine
Scopalamine
Clinical uses of antimuscarinic drugs?
Decrease tremors in parkinsons
Treat motion sickness
Inhibit salivation during oral surgery
Treat insecticide poisoning (decrease effects of anticholinesterases)
MI treatment (blocks vagal response to pain so HR can increase)
Asthma
Pupil dilation during eye examination
In terms of pharmacologic action, what is Ipratropium? Clinical uses?
Muscarinic antagonist
Asthma treatment, inhaled as charged molecules which stay in lung
What is the physiologic effect of cholinesterase inhibitors?
prolong acetylcholine action at synpase –> like giving acetylcholine
Instead of binding once, can bind up to 5 times before being degraded
What are the clinical uses of reversible cholinesterase inhibitors?
Myastenia gravis (autoimmune loss of Ach receptors)
Glaucoma
Alzhiemers
Reversal of nueromuscular block after surgery
What are the therapeutic anti-cholinesterases?
Class name = carbamate
Physostigmine Neostigmine Edrophonium Donezepil Galantanine
What are the main 2 anti-cholinesterases & the main difference between them?
Physostimine, uncharged & enters CNS
Neostigmine, charged & doesn’t enter CNS
What is the short acting anti-cholinesterase used for used for testing myastinea gravis?
Edrophonium
What anti-cholinesterases are used to treat alzhiemers? Safety & efficacy?
Donezepil & Galantanine
Don’t harm, not very effective
What are the clinical uses of irreversible anti-cholinergics?
There are none
It is used as insecticides & nerve gas
In terms of pharmacologic action, what is diisopropylfluorophosphate (DFP)? Clinical uses?
Irreversible anti-colinesterase
Insecticides & nerve gas
What are organophosphates?
Irreversible anti-colinesterase
Who is suseptible to organophosphate poisoning? Treatment?
Young children in rural areas (near farms) & military
Atropine & pralidoxime
How do organophasphates work?
Aging = slow process where organophosphate-cholinesterase complex becomes covalenty & irreversibly bound
In terms of pharmacologic action, what is Atropine? Clinical uses?
Muscarinic receptor blocker
used for organophsophate poisoning. Targets brain where seizures can be life threatening
In terms of pharmacologic action, what is Pralidoxime? Clinical uses?
Used for organophosphate poisoning, binds the poison & removes it if aging process hasn’t had time to occur. Does not cross BBB
What is a disease (not addiction) that can be treated with nicotinic agonist? Why does it work?
Alzhiemers
Cholinergic neurons are most susceptible during alzhiemers –> less Ach
What does muscarinic receptor activation lead to?
Ion channels opening, kinases, phosphatases, protease, gene regulation
Ca, IP3, cAMP, cGMP
Which nicotinic ganglionic antagonist is used in neurosurgery?
trimethapram
