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Pharmacology FINAL > Lecture 8 Part 2 > Flashcards

Lecture 8 Part 2 Flashcards

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1
Q

what is the action of indirect acting cholinomimetics

A

they prevent the hydrolysis of acetylcholine by INHIBITING ACETYLCHOLINESTERASE

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2
Q

Name 3 types of structures that are indirect acting cholinomimetics

A

simple alcohols with a quaternary ammonium group** (edrophonium)

organophosphates

carbamic acid esters of alcohols that have quaternary or tertiary ammonium gorups

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3
Q

what is edrophonium

A

a simple alcohol with a quaternary ammonium group

an indirect acting cholinomimetic

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4
Q

what is echothiophate

A

an organophosphate

indirect acting cholinomimetic

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5
Q

what is neostigmine

A

a carbamic acid ester (carbamate) of an alcohol with quaternary or tertiary ammonium groups that is an indirect acting cholinomimetic

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6
Q

carbaryl

A

cholinesterase inhibitor (indirect cholinomimetic)

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7
Q

physostigmine

A

cholinesterase inhibitor (indirect acting cholineomimetic)

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8
Q

what is the action of organophosphates

A

cause all secretions to occur - pesticides

through inhibiting acetylcholine esterase - INDIRECT acting

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9
Q

name 4 organophosphate cholinesterase inhibitors

A

sarin
paraoxon (parathion)
malaoxon (malathion)
echothiophate

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10
Q

true or false

organophosphates are direct acting

A

FALSE

indirect acting cholinomimetics - inhibit acetylcholine esterase

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11
Q

true or false

organophosphates inhibit acetylcholine esterase

A

true

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12
Q

indirect acting cholinomimetics target acetylcholinesterases as well as….

A

butyrylcholnesterases

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13
Q

explain the mechanism of action of quaternary alcohols and give an example of one

A

edrophonium

reversibly binds electrostatically and hydrogen bonds to the active site of the ACHE receptor to prevent it from accessing acetylcholine and hydrolyzing it

NOT A COVALENT BOND - short lived (2-10mins)

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14
Q

explain the difference in the duration of actions of:

-carbamate esters
-organophosphates
-quaternary alcohols

A

all bind ACHE to prevent it from accessing acetylcholine, thus having indirect cholinomimetic effects

quaternary alcohols have the shortest duration, 2-10 minutes. bond is via electrostatic and hydrogen bonds to the active site

next is carbamate esters. attaches covalently to ACHE and is considerably more RESISTANT. duration is 30mins - 6 hours

longest = organophosphates. undergo initial binding and hydrolysis by the enzyme - results in a PHOSPHORLYATED ACTIVE SITE. covalent phosphate-enzyme bond is extremely stable and hydrolyzes in water at a VERY SLOW RATE (hundreds of hours - aging)

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15
Q

name a carbamic acid (carbamate) ester and state its duration of action

A

neostigmine
30 mins - 6 hours
covalently bound to ACHE

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16
Q

the duration of action of carbamates is determined by…….

A

inhibitor-enzyme complex

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17
Q

what is physostigmine

A

a carbamate (indirect acting)

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18
Q

explain the absorption of quaternary carbamates

A

poor absorption bc of charge
a lot of dose is needed if they are to be administered orally

an exception is physostigmine, which is NO CHARGE

thus, it is well absorbed from alll sites and can be used in the eye
bad side is that it also distributes in the CNS and is thus more toxic

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19
Q

explain the absorption of organophosphate cholinesterase inhibitors and any exceptions

A

all except echothiophate is well absorbed from the skin, gut, lung, and eye

all except echothiophate are distributed to all parts of body INCLUDING CNS – thus CNS toxicity is a poisoning component

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20
Q

explain the half life of organophosphate cholinesterase inhibitors

A

short half life

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21
Q

therapeutic use of edrophonium

A

treatment of myasthenia gravis (ACH not there and degrades so quickly)

ileus, arrhythmias

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22
Q

approximate duration of action of edrophonium

A

5-15 mins

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23
Q

what does neostigmine treat?
also give approximate duration of action

A

myasthenia gravis, ileus, arrhythmias

a carbamate, duration is 0.5-4 hours

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24
Q

what does pyridostigmine treat and what is its duration of action

A

myasthenia gravis
4-6 hours (carbamate)

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25
what does physistigmine treat? approximate duration of action
glaucoma contraction of ciliary body to redeuce intraocular pressure and facilitate outflow of aqueous humor and diminish its secretion 0.5-2 hours (carbamate)
26
what does echothiophate treat and what is its approximate duration of action
glaucoma 100 hours (organophosphate)
27
besides cholinesterase inhibitors, what other drugs can be used to treat glaucoma?
muscarinic stimulants
28
explain the mechanism of how muscarinic stimulants and cholinesterase inhibitors treat glaucoma
glaucoma symptom is INCREASED intraocular pressure these drugs decrease the intraocular pressure by contracting the ciliary body and causing the aqueous humor to flow away and possibly shorten the rate of its secretion
29
direct cholino agonists and cholinesterase inhibitors have been largely replaced by.......
prostaglandin derivatives and topical beta blockers
30
as mentioned, cholinergic agonists and indirect cholinomimetics have been largely replaced by prostaglandin derivatives and topical beta blockers name 1 condition that they are currently still used for
cholinomimetic agonists are used to treat esotropia - strabismus (eye misalignment) in young children
31
if someone suffers from dry mouth, what drug(s) should be used?
acetylcholine agonists or ACHE inhibitors enhance activity of PSNS specifically pilocarpine
32
_________ is used in dry mouth to increase salivary secretion give brand and generic name
pilocarpine (salagen)
33
name 2 drugs for postoperative ileus (paralysis/atony of stomach or bowel) and for urinary retention conditions, and to increase the town of lower esophageal sphincter in pts with reflux esophagus
bethanechol and neostigmine proton pump inhibitors preferred for reflux esophagus tho
34
brand name of pilocarpine
SALAGEN
35
Myasthenia gravis is what kind of disease and what does it affect?
autoimmune disease that affects neuromuscular junctions of skeletal muscle
36
name some symptoms of myasthenia gravis
ptosis diplopia difficulty speaking/swallowing weakness of extremities
37
explain the mechanism of myasthenia gravis
antibodies produced against a1 subunits of the nicotinic receptor channel complex not enough ACH action
38
what drugs are exremely valuable as therapy for myasthenia gravis?
cholinesterase inhibitors like neostigmine and edrophonium long term with pyridostigmine or neostigmine
39
what drug was used to treat supraventricular tachyarrhymias? what is used now?
edrophonium **** short acting cholinesterase inhibitor now, calcium channel blockers are used
40
what drug should be administered to someone who has taken too much of an antimuscaranic drug and is now suffering toxic effects? what are some of these toxic effects? give 2 examples of antimuscarinic drugs that can cause these effects
administer PHYSOSTIMGINE with close monitoring severe behavioral disturbances arrhythmia in adults atropine, tricyclic antidepressants
41
someone has taken too much of direct acting muscarinic stimulants. name 2 potential drugs this could be. what symptoms will be observed? what is the treatment for this?
pilocarpine and choline esters nausea, vomiting, diarrhea, urinary urgency, salivation, sweating, cutaneous vasodilation, bronchial constriction treatment is ATROPINE 1-2mg parenterally --- it is a cholinergic antagonist
42
someone has taken too much acetylcholine and is experiencing negative side effects such as vomiting and diarrhea. what should be given
atropine 1-2mg parenterally
43
which is more important - acute nicotine poisoning or chronic?
chronic is more important bc of cancer risk and COPD risk
44
what are neonicotinoids?
synthetic compounds that cause nicotine toxicity in insects. it's an insecticide
45
what is the fatal dose of nicotine? why have more smokers not died from nicotine poisoning?
40mg or 1 drop of pure liquid most of the nicotine in cigs is destroyed by burning or escapes via sidestream smoke
46
the toxic dose of nicotine is 40mg of 1 drop of pure liquid how have more kids not died from inhaling nicotine insecticides or smoke?
vomitting immediately follows, limiting the absorption
47
explain 3 components of acute nicotine toxicity
it's a CNS stimulant - causes convulsions that can bcome resp arrest/coma respiratory paralysis - skeletal muscle depolarization blockade hypertension and arrhythmias
48
name 3 things that can be used to treat acute nicotine toxicities
atropine - to reverse the muscarinic effects diazepam (anticonvulsant) mechanical ventilation for the neuromuscular blockade
49
nicotine works on what receptor
nicotinic
50
name 5 components of chronic nicotine toxicity
lung cancer COPD stroke asthma reproductive effects (low birth weight, premature bb) diabetes other cancer
51
name 2 drugs that can be used to stop smokine
varenicline - partial nicotinic agonist buproprion - antidepressant
52
name some adverse effects of varenicline
nausea insomnia exacerbation of psychiatric illness - inc anx and depression
53
symptoms of cholinesterase inhibitor toxicity
TOO MUCH ACH muscarinic effects: miosis (pupil constriction), salivation, bronchial constriction, vomiting, diarrhea, CNS convulsions, coma nicotinic effects - depolarizing neuromuscular blockade
54
name 2 types of drugs that are available as pesticides in the US
organophosphates cholinesterase inhibitors
55
what drugs were used as chemical warfare agents and why?
the cholinesterase inhibitors - soman, sarin, VX they induced effects rapidly bc of their large concentrations
56
Treatment for cholinesterase inhibitor toxicity
parenteral atropine in large doses as often as required for muscarine excess watch vital signs - respiration may be impaired decontamination to prevent further absorption - remove clothes, wash skin, etc
57
what are soman, sarin, and VX
cholinesterase inhibitors used in chemical warfare
58
besides atropine, what other drugs may be used for cholinesterase inhibitor toxicity?
pralidoxime benzodiazepine for seizures
59
what is the effect of binding to muscarinic cholinoceptors
parasympathetic nerve stimulation
60
what is the effect of binding to nicotinic cholinoceptors
autonomic ganglia and skeletal muscle motor end plate are stimulated
61
what happens when muscarinic agonists are instilled into the conjunctival sac of the eye?****
-smooth muscle of the iris sphincter contracts (pupil constriction - miosis) -ciliary muscle contracts - resulting in accomadation, aquous humor output USED TO TREAT GLAUCOMA
62
Low doses of Ach cause vaso____. what does this result in
vasodilation causes a reduction in blood pressure --- and a reflex increase heart rate to increase it
63
LARGE doses of acetylcholine do what to the heart?
bradycardia (slow heart beat) decreased AV node conduction velocity hypotension hyperpolarization REDUCED action potential duration decreased contractility of atrial and ventricular cells
64
as mentioned, acetylcholine in low doses causes vasodilation this vasodilation occurs via what mechanism?
activation of M3 receptors
65
what is interesting about the cardiovascular effect of pilocarpine?
in general, cholinomimetics have similar effects to acetylcholine however, pilocarpine is an exception bc when given IV it may produce HYPERTENSION after a brief initial hypotensive response
66
what do muscarinic stimulants do to the respiratory system
bronchoconstriction
67
which glands in the GI tract are stimulated the MOST when muscarinic agonists are adminsitered? which are stimulated less?
most - salivary and gastric glands pancreas and small intestine glands stimulated less
68
true or false when muscarinic agonists are administered, peristaltic activity is decreases and most sphincters are contracted
FALSE - REST AND DIGEST peristaltic activity is increased and most sphincters are RELAXDED
69
what happens to the genitourinary tract when muscarinic agonists are administered
detrusor muscle is stimulated trigone and sphincter muscles relaxx voiding is promoted
70
true or false muscarinic agonists stimulate secretion by THERMOREGULATORY sweat glands, lacrimal, and nasopharyngeal glands
true
71
true or false the CNS contains both nicotinic and muscarinic receptors. the brain is richer in nicotinic sites and the spinal cord contains mostly muscarinic sites
FALSE CNS does contain both but brain is richer in muscarinic sites and spinal cord in nicotinic sites
72
what is M1 receptor involved with in the brain
cognition
73
what is M2 receptor involved with in the brain
nociception and thermoregulation
74
what is M3 involved with in the brain
decreased appetite/body fat
75
_____ receptors allow ACh and nicotine to regulate the release of what 5 neurotransmitters?********
presynapticn nicotine receptors glutamate serotonin GABA dopamine Norepinephrine
76
chronic exposure to nicotine has a DUAL EFFECT at nicotinic receptors explain this statement
there is activation (depolarization) followed by DESENSITIZATION
77
What is the reason for nicotine addiction
activation of nicotinic receptors releases dopamine in the mesolimbic system
78
in high concentrations, nicotine induces ___, ____, and stimulation of the ______
tremor, emesis, and stimulation of the respiratory center
79
effect of nicotine on the cardiovascular system**
sympathomimetic hypertension and increased heart rate
80
effect of nicotine on GI and urinary tracts****
parasympathomimetic increased motility, nausea, vomiting, diarrhea, voiding
81
effect of nicotine on neuromuscular junction
depolarization of the end plate. causes muscle contraction if the action persists, depolarization blockade, resulting in flaccid paralysis (weakness) of skeletal muscles
82
the nicotine action on BOTH parasympathetic and sympathetic ganglia resembles....
simultaneous discharge of of PSNS and SNS ie: cardiovasular is sympathomimetic and GI/urinary and parasympathomimetic
83

Pharmacology FINAL (11 decks)

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